TCSH(1)                      General Commands Manual                     TCSH(1)

       tcsh - C shell with file name completion and command line editing

       tcsh [-bcdefFimnqstvVxX] [-Dname[=value]] [arg ...]
       tcsh -l

       tcsh is an enhanced but completely compatible version of the Berkeley
       UNIX C shell, csh(1).  It is a command language interpreter usable both
       as an interactive login shell and a shell script command processor.  It
       includes a command-line editor (see The command-line editor),
       programmable word completion (see Completion and listing), spelling
       correction (see Spelling correction), a history mechanism (see History
       substitution), job control (see Jobs) and a C-like syntax.  The NEW
       FEATURES section describes major enhancements of tcsh over csh(1).
       Throughout this manual, features of tcsh not found in most csh(1)
       implementations (specifically, the 4.4BSD csh) are labeled with `(+)',
       and features which are present in csh(1) but not usually documented are
       labeled with `(u)'.

   Argument list processing
       If the first argument (argument 0) to the shell is `-' then it is a login
       shell.  A login shell can be also specified by invoking the shell with
       the -l flag as the only argument.

       The rest of the flag arguments are interpreted as follows:

       -b  Forces a ``break'' from option processing, causing any further shell
           arguments to be treated as non-option arguments.  The remaining
           arguments will not be interpreted as shell options.  This may be used
           to pass options to a shell script without confusion or possible
           subterfuge.  The shell will not run a set-user ID script without this

       -c  Commands are read from the following argument (which must be present,
           and must be a single argument), stored in the command shell variable
           for reference, and executed.  Any remaining arguments are placed in
           the argv shell variable.

       -d  The shell loads the directory stack from ~/.cshdirs as described
           under Startup and shutdown, whether or not it is a login shell. (+)

           Sets the environment variable name to value. (Domain/OS only) (+)

       -e  The shell exits if any invoked command terminates abnormally or
           yields a non-zero exit status.

       -f  The shell does not load any resource or startup files, or perform any
           command hashing, and thus starts faster.

       -F  The shell uses fork(2) instead of vfork(2) to spawn processes. This
           is now the default and this option is ignored. (+)

       -i  The shell is interactive and prompts for its top-level input, even if
           it appears to not be a terminal.  Shells are interactive without this
           option if their inputs and outputs are terminals.

       -l  The shell is a login shell.  Applicable only if -l is the only flag

       -m  The shell loads ~/.tcshrc even if it does not belong to the effective
           user.  Newer versions of su(1) can pass -m to the shell. (+)

       -n  The shell parses commands but does not execute them.  This aids in
           debugging shell scripts.

       -q  The shell accepts SIGQUIT (see Signal handling) and behaves when it
           is used under a debugger.  Job control is disabled. (u)

       -s  Command input is taken from the standard input.

       -t  The shell reads and executes a single line of input.  A `\' may be
           used to escape the newline at the end of this line and continue onto
           another line.

       -v  Sets the verbose shell variable, so that command input is echoed
           after history substitution.

       -x  Sets the echo shell variable, so that commands are echoed immediately
           before execution.

       -V  Sets the verbose shell variable even before executing ~/.tcshrc.

       -X  Is to -x as -V is to -v.

           Print a help message on the standard output and exit. (+)

           Print the version/platform/compilation options on the standard output
           and exit.  This information is also contained in the version shell
           variable. (+)

       After processing of flag arguments, if arguments remain but none of the
       -c, -i, -s, or -t options were given, the first argument is taken as the
       name of a file of commands, or ``script'', to be executed.  The shell
       opens this file and saves its name for possible resubstitution by `$0'.
       Because many systems use either the standard version 6 or version 7
       shells whose shell scripts are not compatible with this shell, the shell
       uses such a `standard' shell to execute a script whose first character is
       not a `#', i.e., that does not start with a comment.

       Remaining arguments are placed in the argv shell variable.

   Startup and shutdown
       A login shell begins by executing commands from the system files
       /etc/csh.cshrc and /etc/csh.login.  It then executes commands from files
       in the user's home directory: first ~/.tcshrc (+) or, if ~/.tcshrc is not
       found, ~/.cshrc, then the contents of ~/.history (or the value of the
       histfile shell variable) are loaded into memory, then ~/.login, and
       finally ~/.cshdirs (or the value of the dirsfile shell variable) (+).
       The shell may read /etc/csh.login before instead of after /etc/csh.cshrc,
       and ~/.login before instead of after ~/.tcshrc or ~/.cshrc and
       ~/.history, if so compiled; see the version shell variable. (+)

       Non-login shells read only /etc/csh.cshrc and ~/.tcshrc or ~/.cshrc on

       For examples of startup files, please consult

       Commands like stty(1) and tset(1), which need be run only once per login,
       usually go in one's ~/.login file.  Users who need to use the same set of
       files with both csh(1) and tcsh can have only a ~/.cshrc which checks for
       the existence of the tcsh shell variable (q.v.) before using
       tcsh-specific commands, or can have both a ~/.cshrc and a ~/.tcshrc which
       sources (see the builtin command) ~/.cshrc.  The rest of this manual uses
       `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is not found, ~/.cshrc'.

       In the normal case, the shell begins reading commands from the terminal,
       prompting with `> '.  (Processing of arguments and the use of the shell
       to process files containing command scripts are described later.)  The
       shell repeatedly reads a line of command input, breaks it into words,
       places it on the command history list, parses it and executes each
       command in the line.

       One can log out by typing `^D' on an empty line, `logout' or `login' or
       via the shell's autologout mechanism (see the autologout shell variable).
       When a login shell terminates it sets the logout shell variable to
       `normal' or `automatic' as appropriate, then executes commands from the
       files /etc/csh.logout and ~/.logout.  The shell may drop DTR on logout if
       so compiled; see the version shell variable.

       The names of the system login and logout files vary from system to system
       for compatibility with different csh(1) variants; see FILES.

       We first describe The command-line editor.  The Completion and listing
       and Spelling correction sections describe two sets of functionality that
       are implemented as editor commands but which deserve their own treatment.
       Finally, Editor commands lists and describes the editor commands specific
       to the shell and their default bindings.

   The command-line editor (+)
       Command-line input can be edited using key sequences much like those used
       in emacs(1) or vi(1).  The editor is active only when the edit shell
       variable is set, which it is by default in interactive shells.  The
       bindkey builtin can display and change key bindings.  emacs(1)-style key
       bindings are used by default (unless the shell was compiled otherwise;
       see the version shell variable), but bindkey can change the key bindings
       to vi(1)-style bindings en masse.

       The shell always binds the arrow keys (as defined in the TERMCAP
       environment variable) to

           down    down-history
           up      up-history
           left    backward-char
           right   forward-char

       unless doing so would alter another single-character binding.  One can
       set the arrow key escape sequences to the empty string with settc to
       prevent these bindings.  The ANSI/VT100 sequences for arrow keys are
       always bound.

       Other key bindings are, for the most part, what emacs(1) and vi(1) users
       would expect and can easily be displayed by bindkey, so there is no need
       to list them here.  Likewise, bindkey can list the editor commands with a
       short description of each.  Certain key bindings have different behavior
       depending if emacs(1) or vi(1) style bindings are being used; see vimode
       for more information.

       Note that editor commands do not have the same notion of a ``word'' as
       does the shell.  The editor delimits words with any non-alphanumeric
       characters not in the shell variable wordchars, while the shell
       recognizes only whitespace and some of the characters with special
       meanings to it, listed under Lexical structure.

   Completion and listing (+)
       The shell is often able to complete words when given a unique
       abbreviation.  Type part of a word (for example `ls /usr/lost') and hit
       the tab key to run the complete-word editor command.  The shell completes
       the filename `/usr/lost' to `/usr/lost+found/', replacing the incomplete
       word with the complete word in the input buffer.  (Note the terminal `/';
       completion adds a `/' to the end of completed directories and a space to
       the end of other completed words, to speed typing and provide a visual
       indicator of successful completion.  The addsuffix shell variable can be
       unset to prevent this.)  If no match is found (perhaps `/usr/lost+found'
       doesn't exist), the terminal bell rings.  If the word is already complete
       (perhaps there is a `/usr/lost' on your system, or perhaps you were
       thinking too far ahead and typed the whole thing) a `/' or space is added
       to the end if it isn't already there.

       Completion works anywhere in the line, not at just the end; completed
       text pushes the rest of the line to the right.  Completion in the middle
       of a word often results in leftover characters to the right of the cursor
       that need to be deleted.

       Commands and variables can be completed in much the same way.  For
       example, typing `em[tab]' would complete `em' to `emacs' if emacs were
       the only command on your system beginning with `em'.  Completion can find
       a command in any directory in path or if given a full pathname.  Typing
       `echo $ar[tab]' would complete `$ar' to `$argv' if no other variable
       began with `ar'.

       The shell parses the input buffer to determine whether the word you want
       to complete should be completed as a filename, command or variable.  The
       first word in the buffer and the first word following `;', `|', `|&',
       `&&' or `||' is considered to be a command.  A word beginning with `$' is
       considered to be a variable.  Anything else is a filename.  An empty line
       is `completed' as a filename.

       You can list the possible completions of a word at any time by typing
       `^D' to run the delete-char-or-list-or-eof editor command.  The shell
       lists the possible completions using the ls-F builtin (q.v.)  and
       reprints the prompt and unfinished command line, for example:

           > ls /usr/l[^D]
           lbin/       lib/        local/      lost+found/
           > ls /usr/l

       If the autolist shell variable is set, the shell lists the remaining
       choices (if any) whenever completion fails:

           > set autolist
           > nm /usr/lib/libt[tab]
           libtermcap.a@ libtermlib.a@
           > nm /usr/lib/libterm

       If autolist is set to `ambiguous', choices are listed only when
       completion fails and adds no new characters to the word being completed.

       A filename to be completed can contain variables, your own or others'
       home directories abbreviated with `~' (see Filename substitution) and
       directory stack entries abbreviated with `=' (see Directory stack
       substitution).  For example,

           > ls ~k[^D]
           kahn    kas     kellogg
           > ls ~ke[tab]
           > ls ~kellogg/


           > set local = /usr/local
           > ls $lo[tab]
           > ls $local/[^D]
           bin/ etc/ lib/ man/ src/
           > ls $local/

       Note that variables can also be expanded explicitly with the expand-
       variables editor command.

       delete-char-or-list-or-eof lists at only the end of the line; in the
       middle of a line it deletes the character under the cursor and on an
       empty line it logs one out or, if ignoreeof is set, does nothing.
       `M-^D', bound to the editor command list-choices, lists completion
       possibilities anywhere on a line, and list-choices (or any one of the
       related editor commands that do or don't delete, list and/or log out,
       listed under delete-char-or-list-or-eof) can be bound to `^D' with the
       bindkey builtin command if so desired.

       The complete-word-fwd and complete-word-back editor commands (not bound
       to any keys by default) can be used to cycle up and down through the list
       of possible completions, replacing the current word with the next or
       previous word in the list.

       The shell variable fignore can be set to a list of suffixes to be ignored
       by completion.  Consider the following:

           > ls
           Makefile        condiments.h~   main.o          side.c
           README          main.c          meal            side.o
           condiments.h    main.c~
           > set fignore = (.o \~)
           > emacs ma[^D]
           main.c   main.c~  main.o
           > emacs ma[tab]
           > emacs main.c

       `main.c~' and `main.o' are ignored by completion (but not listing),
       because they end in suffixes in fignore.  Note that a `\' was needed in
       front of `~' to prevent it from being expanded to home as described under
       Filename substitution.  fignore is ignored if only one completion is

       If the complete shell variable is set to `enhance', completion 1) ignores
       case and 2) considers periods, hyphens and underscores (`.', `-' and `_')
       to be word separators and hyphens and underscores to be equivalent.  If
       you had the following files

           comp.lang.c      comp.lang.perl   comp.std.c++
           comp.lang.c++    comp.std.c

       and typed `mail -f c.l.c[tab]', it would be completed to `mail -f
       comp.lang.c', and ^D would list `comp.lang.c' and `comp.lang.c++'.  `mail
       -f c..c++[^D]' would list `comp.lang.c++' and `comp.std.c++'.  Typing `rm
       a--file[^D]' in the following directory

           A_silly_file    a-hyphenated-file    another_silly_file

       would list all three files, because case is ignored and hyphens and
       underscores are equivalent.  Periods, however, are not equivalent to
       hyphens or underscores.

       If the complete shell variable is set to `Enhance', completion ignores
       case and differences between a hyphen and an underscore word separator
       only when the user types a lowercase character or a hyphen.  Entering an
       uppercase character or an underscore will not match the corresponding
       lowercase character or hyphen word separator.  Typing `rm a--file[^D]' in
       the directory of the previous example would still list all three files,
       but typing `rm A--file' would match only `A_silly_file' and typing `rm
       a__file[^D]' would match just `A_silly_file' and `another_silly_file'
       because the user explicitly used an uppercase or an underscore character.

       Completion and listing are affected by several other shell variables:
       recexact can be set to complete on the shortest possible unique match,
       even if more typing might result in a longer match:

           > ls
           fodder   foo      food     foonly
           > set recexact
           > rm fo[tab]

       just beeps, because `fo' could expand to `fod' or `foo', but if we type
       another `o',

           > rm foo[tab]
           > rm foo

       the completion completes on `foo', even though `food' and `foonly' also
       match.  autoexpand can be set to run the expand-history editor command
       before each completion attempt, autocorrect can be set to spelling-
       correct the word to be completed (see Spelling correction) before each
       completion attempt and correct can be set to complete commands
       automatically after one hits `return'.  matchbeep can be set to make
       completion beep or not beep in a variety of situations, and nobeep can be
       set to never beep at all.  nostat can be set to a list of directories
       and/or patterns that match directories to prevent the completion
       mechanism from stat(2)ing those directories.  listmax and listmaxrows can
       be set to limit the number of items and rows (respectively) that are
       listed without asking first.  recognize_only_executables can be set to
       make the shell list only executables when listing commands, but it is
       quite slow.

       Finally, the complete builtin command can be used to tell the shell how
       to complete words other than filenames, commands and variables.
       Completion and listing do not work on glob-patterns (see Filename
       substitution), but the list-glob and expand-glob editor commands perform
       equivalent functions for glob-patterns.

   Spelling correction (+)
       The shell can sometimes correct the spelling of filenames, commands and
       variable names as well as completing and listing them.

       Individual words can be spelling-corrected with the spell-word editor
       command (usually bound to M-s and M-S) and the entire input buffer with
       spell-line (usually bound to M-$).  The correct shell variable can be set
       to `cmd' to correct the command name or `all' to correct the entire line
       each time return is typed, and autocorrect can be set to correct the word
       to be completed before each completion attempt.

       When spelling correction is invoked in any of these ways and the shell
       thinks that any part of the command line is misspelled, it prompts with
       the corrected line:

           > set correct = cmd
           > lz /usr/bin
           CORRECT>ls /usr/bin (y|n|e|a)?

       One can answer `y' or space to execute the corrected line, `e' to leave
       the uncorrected command in the input buffer, `a' to abort the command as
       if `^C' had been hit, and anything else to execute the original line

       Spelling correction recognizes user-defined completions (see the complete
       builtin command).  If an input word in a position for which a completion
       is defined resembles a word in the completion list, spelling correction
       registers a misspelling and suggests the latter word as a correction.
       However, if the input word does not match any of the possible completions
       for that position, spelling correction does not register a misspelling.

       Like completion, spelling correction works anywhere in the line, pushing
       the rest of the line to the right and possibly leaving extra characters
       to the right of the cursor.

   Editor commands (+)
       `bindkey' lists key bindings and `bindkey -l' lists and briefly describes
       editor commands.  Only new or especially interesting editor commands are
       described here.  See emacs(1) and vi(1) for descriptions of each editor's
       key bindings.

       The character or characters to which each command is bound by default is
       given in parentheses.  `^character' means a control character and
       `M-character' a meta character, typed as escape-character on terminals
       without a meta key.  Case counts, but commands that are bound to letters
       by default are bound to both lower- and uppercase letters for

       backward-char (^B, left)
               Move back a character.  Cursor behavior modified by vimode.

       backward-delete-word (M-^H, M-^?)
               Cut from beginning of current word to cursor - saved in cut
               buffer.  Word boundary behavior modified by vimode.

       backward-word (M-b, M-B)
               Move to beginning of current word.  Word boundary and cursor
               behavior modified by vimode.

       beginning-of-line (^A, home)
               Move to beginning of line.  Cursor behavior modified by vimode.

       capitalize-word (M-c, M-C)
               Capitalize the characters from cursor to end of current word.
               Word boundary behavior modified by vimode.

       complete-word (tab)
               Completes a word as described under Completion and listing.

       complete-word-back (not bound)
               Like complete-word-fwd, but steps up from the end of the list.

       complete-word-fwd (not bound)
               Replaces the current word with the first word in the list of
               possible completions.  May be repeated to step down through the
               list.  At the end of the list, beeps and reverts to the
               incomplete word.

       complete-word-raw (^X-tab)
               Like complete-word, but ignores user-defined completions.

       copy-prev-word (M-^_)
               Copies the previous word in the current line into the input
               buffer.  See also insert-last-word.  Word boundary behavior
               modified by vimode.

       dabbrev-expand (M-/)
               Expands the current word to the most recent preceding one for
               which the current is a leading substring, wrapping around the
               history list (once) if necessary.  Repeating dabbrev-expand
               without any intervening typing changes to the next previous word
               etc., skipping identical matches much like history-search-
               backward does.

       delete-char (not bound)
               Deletes the character under the cursor.  See also delete-char-or-
               list-or-eof.  Cursor behavior modified by vimode.

       delete-char-or-eof (not bound)
               Does delete-char if there is a character under the cursor or end-
               of-file on an empty line.  See also delete-char-or-list-or-eof.
               Cursor behavior modified by vimode.

       delete-char-or-list (not bound)
               Does delete-char if there is a character under the cursor or
               list-choices at the end of the line.  See also delete-char-or-

       delete-char-or-list-or-eof (^D)
               Does delete-char if there is a character under the cursor, list-
               choices at the end of the line or end-of-file on an empty line.
               See also those three commands, each of which does only a single
               action, and delete-char-or-eof, delete-char-or-list and list-or-
               eof, each of which does a different two out of the three.

       delete-word (M-d, M-D)
               Cut from cursor to end of current word - save in cut buffer.
               Word boundary behavior modified by vimode.

       down-history (down-arrow, ^N)
               Like up-history, but steps down, stopping at the original input

       downcase-word (M-l, M-L)
               Lowercase the characters from cursor to end of current word.
               Word boundary behavior modified by vimode.

       end-of-file (not bound)
               Signals an end of file, causing the shell to exit unless the
               ignoreeof shell variable (q.v.) is set to prevent this.  See also

       end-of-line (^E, end)
               Move cursor to end of line.  Cursor behavior modified by vimode.

       expand-history (M-space)
               Expands history substitutions in the current word.  See History
               substitution.  See also magic-space, toggle-literal-history and
               the autoexpand shell variable.

       expand-glob (^X-*)
               Expands the glob-pattern to the left of the cursor.  See Filename

       expand-line (not bound)
               Like expand-history, but expands history substitutions in each
               word in the input buffer.

       expand-variables (^X-$)
               Expands the variable to the left of the cursor.  See Variable

       forward-char (^F, right)
               Move forward one character.  Cursor behavior modified by vimode.

       forward-word (M-f, M-F)
               Move forward to end of current word.  Word boundary and cursor
               behavior modified by vimode.

       history-search-backward (M-p, M-P)
               Searches backwards through the history list for a command
               beginning with the current contents of the input buffer up to the
               cursor and copies it into the input buffer.  The search string
               may be a glob-pattern (see Filename substitution) containing `*',
               `?', `[]' or `{}'.  up-history and down-history will proceed from
               the appropriate point in the history list.  Emacs mode only.  See
               also history-search-forward and i-search-back.

       history-search-forward (M-n, M-N)
               Like history-search-backward, but searches forward.

       i-search-back (not bound)
               Searches backward like history-search-backward, copies the first
               match into the input buffer with the cursor positioned at the end
               of the pattern, and prompts with `bck: ' and the first match.
               Additional characters may be typed to extend the search, i-
               search-back may be typed to continue searching with the same
               pattern, wrapping around the history list if necessary, (i-
               search-back must be bound to a single character for this to work)
               or one of the following special characters may be typed:

                   ^W      Appends the rest of the word under the cursor to the
                           search pattern.
                   delete (or any character bound to backward-delete-char)
                           Undoes the effect of the last character typed and
                           deletes a character from the search pattern if
                   ^G      If the previous search was successful, aborts the
                           entire search.  If not, goes back to the last
                           successful search.
                   escape  Ends the search, leaving the current line in the
                           input buffer.

               Any other character not bound to self-insert-command terminates
               the search, leaving the current line in the input buffer, and is
               then interpreted as normal input.  In particular, a carriage
               return causes the current line to be executed.  See also i-
               search-fwd and history-search-backward.  Word boundary behavior
               modified by vimode.

       i-search-fwd (not bound)
               Like i-search-back, but searches forward.  Word boundary behavior
               modified by vimode.

       insert-last-word (M-_)
               Inserts the last word of the previous input line (`!$') into the
               input buffer.  See also copy-prev-word.

       list-choices (M-^D)
               Lists completion possibilities as described under Completion and
               listing.  See also delete-char-or-list-or-eof and list-choices-

       list-choices-raw (^X-^D)
               Like list-choices, but ignores user-defined completions.

       list-glob (^X-g, ^X-G)
               Lists (via the ls-F builtin) matches to the glob-pattern (see
               Filename substitution) to the left of the cursor.

       list-or-eof (not bound)
               Does list-choices or end-of-file on an empty line.  See also

       magic-space (not bound)
               Expands history substitutions in the current line, like expand-
               history, and inserts a space.  magic-space is designed to be
               bound to the space bar, but is not bound by default.

       normalize-command (^X-?)
               Searches for the current word in PATH and, if it is found,
               replaces it with the full path to the executable.  Special
               characters are quoted.  Aliases are expanded and quoted but
               commands within aliases are not.  This command is useful with
               commands that take commands as arguments, e.g., `dbx' and `sh

       normalize-path (^X-n, ^X-N)
               Expands the current word as described under the `expand' setting
               of the symlinks shell variable.

       overwrite-mode (unbound)
               Toggles between input and overwrite modes.

       run-fg-editor (M-^Z)
               Saves the current input line and looks for a stopped job where
               the file name portion of its first word is found in the editors
               shell variable.  If editors is not set, then the file name
               portion of the EDITOR environment variable (`ed' if unset) and
               the VISUAL environment variable (`vi' if unset) will be used.  If
               such a job is found, it is restarted as if `fg %job' had been
               typed.  This is used to toggle back and forth between an editor
               and the shell easily.  Some people bind this command to `^Z' so
               they can do this even more easily.

       run-help (M-h, M-H)
               Searches for documentation on the current command, using the same
               notion of `current command' as the completion routines, and
               prints it.  There is no way to use a pager; run-help is designed
               for short help files.  If the special alias helpcommand is
               defined, it is run with the command name as a sole argument.
               Else, documentation should be in a file named command.help,
               command.1, command.6, command.8 or command, which should be in
               one of the directories listed in the HPATH environment variable.
               If there is more than one help file only the first is printed.

       self-insert-command (text characters)
               In insert mode (the default), inserts the typed character into
               the input line after the character under the cursor.  In
               overwrite mode, replaces the character under the cursor with the
               typed character.  The input mode is normally preserved between
               lines, but the inputmode shell variable can be set to `insert' or
               `overwrite' to put the editor in that mode at the beginning of
               each line.  See also overwrite-mode.

       sequence-lead-in (arrow prefix, meta prefix, ^X)
               Indicates that the following characters are part of a multi-key
               sequence.  Binding a command to a multi-key sequence really
               creates two bindings: the first character to sequence-lead-in and
               the whole sequence to the command.  All sequences beginning with
               a character bound to sequence-lead-in are effectively bound to
               undefined-key unless bound to another command.

       spell-line (M-$)
               Attempts to correct the spelling of each word in the input
               buffer, like spell-word, but ignores words whose first character
               is one of `-', `!', `^' or `%', or which contain `\', `*' or `?',
               to avoid problems with switches, substitutions and the like.  See
               Spelling correction.

       spell-word (M-s, M-S)
               Attempts to correct the spelling of the current word as described
               under Spelling correction.  Checks each component of a word which
               appears to be a pathname.

       toggle-literal-history (M-r, M-R)
               Expands or `unexpands' history substitutions in the input buffer.
               See also expand-history and the autoexpand shell variable.

       undefined-key (any unbound key)

       up-history (up-arrow, ^P)
               Copies the previous entry in the history list into the input
               buffer.  If histlit is set, uses the literal form of the entry.
               May be repeated to step up through the history list, stopping at
               the top.

       upcase-word (M-u, M-U)
               Uppercase the characters from cursor to end of current word.
               Word boundary behavior modified by vimode.

       vi-beginning-of-next-word (not bound)
               Vi goto the beginning of next word.  Word boundary and cursor
               behavior modified by vimode.

       vi-eword (not bound)
               Vi move to the end of the current word.  Word boundary behavior
               modified by vimode.

       vi-search-back (?)
               Prompts with `?' for a search string (which may be a glob-
               pattern, as with history-search-backward), searches for it and
               copies it into the input buffer.  The bell rings if no match is
               found.  Hitting return ends the search and leaves the last match
               in the input buffer.  Hitting escape ends the search and executes
               the match.  vi mode only.

       vi-search-fwd (/)
               Like vi-search-back, but searches forward.

       which-command (M-?)
               Does a which (see the description of the builtin command) on the
               first word of the input buffer.

       yank-pop (M-y)
               When executed immediately after a yank or another yank-pop,
               replaces the yanked string with the next previous string from the
               killring. This also has the effect of rotating the killring, such
               that this string will be considered the most recently killed by a
               later yank command. Repeating yank-pop will cycle through the
               killring any number of times.

   Lexical structure
       The shell splits input lines into words at blanks and tabs.  The special
       characters `&', `|', `;', `<', `>', `(', and `)' and the doubled
       characters `&&', `||', `<<' and `>>' are always separate words, whether
       or not they are surrounded by whitespace.

       When the shell's input is not a terminal, the character `#' is taken to
       begin a comment.  Each `#' and the rest of the input line on which it
       appears is discarded before further parsing.

       A special character (including a blank or tab) may be prevented from
       having its special meaning, and possibly made part of another word, by
       preceding it with a backslash (`\') or enclosing it in single (`''),
       double (`"') or backward (``') quotes.  When not otherwise quoted a
       newline preceded by a `\' is equivalent to a blank, but inside quotes
       this sequence results in a newline.

       Furthermore, all Substitutions (see below) except History substitution
       can be prevented by enclosing the strings (or parts of strings) in which
       they appear with single quotes or by quoting the crucial character(s)
       (e.g., `$' or ``' for Variable substitution or Command substitution
       respectively) with `\'.  (Alias substitution is no exception: quoting in
       any way any character of a word for which an alias has been defined
       prevents substitution of the alias.  The usual way of quoting an alias is
       to precede it with a backslash.) History substitution is prevented by
       backslashes but not by single quotes.  Strings quoted with double or
       backward quotes undergo Variable substitution and Command substitution,
       but other substitutions are prevented.

       Text inside single or double quotes becomes a single word (or part of
       one).  Metacharacters in these strings, including blanks and tabs, do not
       form separate words.  Only in one special case (see Command substitution
       below) can a double-quoted string yield parts of more than one word;
       single-quoted strings never do.  Backward quotes are special: they signal
       Command substitution (q.v.), which may result in more than one word.

       Quoting complex strings, particularly strings which themselves contain
       quoting characters, can be confusing.  Remember that quotes need not be
       used as they are in human writing!  It may be easier to quote not an
       entire string, but only those parts of the string which need quoting,
       using different types of quoting to do so if appropriate.

       The backslash_quote shell variable (q.v.) can be set to make backslashes
       always quote `\', `'', and `"'.  (+) This may make complex quoting tasks
       easier, but it can cause syntax errors in csh(1) scripts.

       We now describe the various transformations the shell performs on the
       input in the order in which they occur.  We note in passing the data
       structures involved and the commands and variables which affect them.
       Remember that substitutions can be prevented by quoting as described
       under Lexical structure.

   History substitution
       Each command, or ``event'', input from the terminal is saved in the
       history list.  The previous command is always saved, and the history
       shell variable can be set to a number to save that many commands.  The
       histdup shell variable can be set to not save duplicate events or
       consecutive duplicate events.

       Saved commands are numbered sequentially from 1 and stamped with the
       time.  It is not usually necessary to use event numbers, but the current
       event number can be made part of the prompt by placing an `!' in the
       prompt shell variable.

       The shell actually saves history in expanded and literal (unexpanded)
       forms.  If the histlit shell variable is set, commands that display and
       store history use the literal form.

       The history builtin command can print, store in a file, restore and clear
       the history list at any time, and the savehist and histfile shell
       variables can be set to store the history list automatically on logout
       and restore it on login.

       History substitutions introduce words from the history list into the
       input stream, making it easy to repeat commands, repeat arguments of a
       previous command in the current command, or fix spelling mistakes in the
       previous command with little typing and a high degree of confidence.

       History substitutions begin with the character `!'.  They may begin
       anywhere in the input stream, but they do not nest.  The `!' may be
       preceded by a `\' to prevent its special meaning; for convenience, a `!'
       is passed unchanged when it is followed by a blank, tab, newline, `=' or
       `('.  History substitutions also occur when an input line begins with
       `^'.  This special abbreviation will be described later.  The characters
       used to signal history substitution (`!' and `^') can be changed by
       setting the histchars shell variable.  Any input line which contains a
       history substitution is printed before it is executed.

       A history substitution may have an ``event specification'', which
       indicates the event from which words are to be taken, a ``word
       designator'', which selects particular words from the chosen event,
       and/or a ``modifier'', which manipulates the selected words.

       An event specification can be

           n       A number, referring to a particular event
           -n      An offset, referring to the event n before the current event
           #       The current event.  This should be used carefully in csh(1),
                   where there is no check for recursion.  tcsh allows 10 levels
                   of recursion.  (+)
           !       The previous event (equivalent to `-1')
           s       The most recent event whose first word begins with the string
           ?s?     The most recent event which contains the string s.  The
                   second `?' can be omitted if it is immediately followed by a

       For example, consider this bit of someone's history list:

            9  8:30    nroff -man wumpus.man
           10  8:31    cp wumpus.man wumpus.man.old
           11  8:36    vi wumpus.man
           12  8:37    diff wumpus.man.old wumpus.man

       The commands are shown with their event numbers and time stamps.  The
       current event, which we haven't typed in yet, is event 13.  `!11' and
       `!-2' refer to event 11.  `!!' refers to the previous event, 12.  `!!'
       can be abbreviated `!' if it is followed by `:' (`:' is described below).
       `!n' refers to event 9, which begins with `n'.  `!?old?' also refers to
       event 12, which contains `old'.  Without word designators or modifiers
       history references simply expand to the entire event, so we might type
       `!cp' to redo the copy command or `!!|more' if the `diff' output scrolled
       off the top of the screen.

       History references may be insulated from the surrounding text with braces
       if necessary.  For example, `!vdoc' would look for a command beginning
       with `vdoc', and, in this example, not find one, but `!{v}doc' would
       expand unambiguously to `vi wumpus.mandoc'.  Even in braces, history
       substitutions do not nest.

       (+) While csh(1) expands, for example, `!3d' to event 3 with the letter
       `d' appended to it, tcsh expands it to the last event beginning with
       `3d'; only completely numeric arguments are treated as event numbers.
       This makes it possible to recall events beginning with numbers.  To
       expand `!3d' as in csh(1) say `!{3}d'.

       To select words from an event we can follow the event specification by a
       `:' and a designator for the desired words.  The words of an input line
       are numbered from 0, the first (usually command) word being 0, the second
       word (first argument) being 1, etc.  The basic word designators are:

           0       The first (command) word
           n       The nth argument
           ^       The first argument, equivalent to `1'
           $       The last argument
           %       The word matched by an ?s? search
           x-y     A range of words
           -y      Equivalent to `0-y'
           *       Equivalent to `^-$', but returns nothing if the event
                   contains only 1 word
           x*      Equivalent to `x-$'
           x-      Equivalent to `x*', but omitting the last word (`$')

       Selected words are inserted into the command line separated by single
       blanks.  For example, the `diff' command in the previous example might
       have been typed as `diff !!:1.old !!:1' (using `:1' to select the first
       argument from the previous event) or `diff !-2:2 !-2:1' to select and
       swap the arguments from the `cp' command.  If we didn't care about the
       order of the `diff' we might have said `diff !-2:1-2' or simply `diff
       !-2:*'.  The `cp' command might have been written `cp wumpus.man
       !#:1.old', using `#' to refer to the current event.  `!n:- hurkle.man'
       would reuse the first two words from the `nroff' command to say `nroff
       -man hurkle.man'.

       The `:' separating the event specification from the word designator can
       be omitted if the argument selector begins with a `^', `$', `*', `%' or
       `-'.  For example, our `diff' command might have been `diff !!^.old !!^'
       or, equivalently, `diff !!$.old !!$'.  However, if `!!' is abbreviated
       `!', an argument selector beginning with `-' will be interpreted as an
       event specification.

       A history reference may have a word designator but no event
       specification.  It then references the previous command.  Continuing our
       `diff' example, we could have said simply `diff !^.old !^' or, to get the
       arguments in the opposite order, just `diff !*'.

       The word or words in a history reference can be edited, or ``modified'',
       by following it with one or more modifiers, each preceded by a `:':

           h       Remove a trailing pathname component, leaving the head.
           t       Remove all leading pathname components, leaving the tail.
           r       Remove a filename extension `.xxx', leaving the root name.
           e       Remove all but the extension.
           u       Uppercase the first lowercase letter.
           l       Lowercase the first uppercase letter.
           s/l/r/  Substitute l for r.  l is simply a string like r, not a
                   regular expression as in the eponymous ed(1) command.  Any
                   character may be used as the delimiter in place of `/'; a `\'
                   can be used to quote the delimiter inside l and r.  The
                   character `&' in the r is replaced by l; `\' also quotes `&'.
                   If l is empty (``''), the l from a previous substitution or
                   the s from a previous search or event number in event
                   specification is used.  The trailing delimiter may be omitted
                   if it is immediately followed by a newline.
           &       Repeat the previous substitution.
           g       Apply the following modifier once to each word.
           a (+)   Apply the following modifier as many times as possible to a
                   single word.  `a' and `g' can be used together to apply a
                   modifier globally.  With the `s' modifier, only the patterns
                   contained in the original word are substituted, not patterns
                   that contain any substitution result.
           p       Print the new command line but do not execute it.
           q       Quote the substituted words, preventing further
           x       Like q, but break into words at blanks, tabs and newlines.

       Modifiers are applied to only the first modifiable word (unless `g' is
       used).  It is an error for no word to be modifiable.

       For example, the `diff' command might have been written as `diff
       wumpus.man.old !#^:r', using `:r' to remove `.old' from the first
       argument on the same line (`!#^').  We could say `echo hello out there',
       then `echo !*:u' to capitalize `hello', `echo !*:au' to say it out loud,
       or `echo !*:agu' to really shout.  We might follow `mail -s "I forgot my
       password" rot' with `!:s/rot/root' to correct the spelling of `root' (but
       see Spelling correction for a different approach).

       There is a special abbreviation for substitutions.  `^', when it is the
       first character on an input line, is equivalent to `!:s^'.  Thus we might
       have said `^rot^root' to make the spelling correction in the previous
       example.  This is the only history substitution which does not explicitly
       begin with `!'.

       (+) In csh as such, only one modifier may be applied to each history or
       variable expansion.  In tcsh, more than one may be used, for example

           % mv wumpus.man /usr/man/man1/wumpus.1
           % man !$:t:r
           man wumpus

       In csh, the result would be `wumpus.1:r'.  A substitution followed by a
       colon may need to be insulated from it with braces:

           > mv a.out /usr/games/wumpus
           > setenv PATH !$:h:$PATH
           Bad ! modifier: $.
           > setenv PATH !{-2$:h}:$PATH
           setenv PATH /usr/games:/bin:/usr/bin:.

       The first attempt would succeed in csh but fails in tcsh, because tcsh
       expects another modifier after the second colon rather than `$'.

       Finally, history can be accessed through the editor as well as through
       the substitutions just described.  The up- and down-history, history-
       search-backward and -forward, i-search-back and -fwd, vi-search-back and
       -fwd, copy-prev-word and insert-last-word editor commands search for
       events in the history list and copy them into the input buffer.  The
       toggle-literal-history editor command switches between the expanded and
       literal forms of history lines in the input buffer.  expand-history and
       expand-line expand history substitutions in the current word and in the
       entire input buffer respectively.

   Alias substitution
       The shell maintains a list of aliases which can be set, unset and printed
       by the alias and unalias commands.  After a command line is parsed into
       simple commands (see Commands) the first word of each command, left-to-
       right, is checked to see if it has an alias.  If so, the first word is
       replaced by the alias.  If the alias contains a history reference, it
       undergoes History substitution (q.v.) as though the original command were
       the previous input line.  If the alias does not contain a history
       reference, the argument list is left untouched.

       Thus if the alias for `ls' were `ls -l' the command `ls /usr' would
       become `ls -l /usr', the argument list here being undisturbed.  If the
       alias for `lookup' were `grep !^ /etc/passwd' then `lookup bill' would
       become `grep bill /etc/passwd'.  Aliases can be used to introduce parser
       metasyntax.  For example, `alias print 'pr \!* | lpr'' defines a
       ``command'' (`print') which pr(1)s its arguments to the line printer.

       Alias substitution is repeated until the first word of the command has no
       alias.  If an alias substitution does not change the first word (as in
       the previous example) it is flagged to prevent a loop.  Other loops are
       detected and cause an error.

       Some aliases are referred to by the shell; see Special aliases.

   Variable substitution
       The shell maintains a list of variables, each of which has as value a
       list of zero or more words.  The values of shell variables can be
       displayed and changed with the set and unset commands.  The system
       maintains its own list of ``environment'' variables.  These can be
       displayed and changed with printenv, setenv and unsetenv.

       (+) Variables may be made read-only with `set -r' (q.v.).  Read-only
       variables may not be modified or unset; attempting to do so will cause an
       error.  Once made read-only, a variable cannot be made writable, so `set
       -r' should be used with caution.  Environment variables cannot be made

       Some variables are set by the shell or referred to by it.  For instance,
       the argv variable is an image of the shell's argument list, and words of
       this variable's value are referred to in special ways.  Some of the
       variables referred to by the shell are toggles; the shell does not care
       what their value is, only whether they are set or not.  For instance, the
       verbose variable is a toggle which causes command input to be echoed.
       The -v command line option sets this variable.  Special shell variables
       lists all variables which are referred to by the shell.

       Other operations treat variables numerically.  The `@' command permits
       numeric calculations to be performed and the result assigned to a
       variable.  Variable values are, however, always represented as (zero or
       more) strings.  For the purposes of numeric operations, the null string
       is considered to be zero, and the second and subsequent words of multi-
       word values are ignored.

       After the input line is aliased and parsed, and before each command is
       executed, variable substitution is performed keyed by `$' characters.
       This expansion can be prevented by preceding the `$' with a `\' except
       within `"'s where it always occurs, and within `''s where it never
       occurs.  Strings quoted by ``' are interpreted later (see Command
       substitution below) so `$' substitution does not occur there until later,
       if at all.  A `$' is passed unchanged if followed by a blank, tab, or

       Input/output redirections are recognized before variable expansion, and
       are variable expanded separately.  Otherwise, the command name and entire
       argument list are expanded together.  It is thus possible for the first
       (command) word (to this point) to generate more than one word, the first
       of which becomes the command name, and the rest of which become

       Unless enclosed in `"' or given the `:q' modifier the results of variable
       substitution may eventually be command and filename substituted.  Within
       `"', a variable whose value consists of multiple words expands to a
       (portion of a) single word, with the words of the variable's value
       separated by blanks.  When the `:q' modifier is applied to a substitution
       the variable will expand to multiple words with each word separated by a
       blank and quoted to prevent later command or filename substitution.

       The following metasequences are provided for introducing variable values
       into the shell input.  Except as noted, it is an error to reference a
       variable which is not set.

       ${name} Substitutes the words of the value of variable name, each
               separated by a blank.  Braces insulate name from following
               characters which would otherwise be part of it.  Shell variables
               have names consisting of letters and digits starting with a
               letter.  The underscore character is considered a letter.  If
               name is not a shell variable, but is set in the environment, then
               that value is returned (but some of the other forms given below
               are not available in this case).
               Substitutes only the selected words from the value of name.  The
               selector is subjected to `$' substitution and may consist of a
               single number or two numbers separated by a `-'.  The first word
               of a variable's value is numbered `1'.  If the first number of a
               range is omitted it defaults to `1'.  If the last member of a
               range is omitted it defaults to `$#name'.  The selector `*'
               selects all words.  It is not an error for a range to be empty if
               the second argument is omitted or in range.
       $0      Substitutes the name of the file from which command input is
               being read.  An error occurs if the name is not known.
               Equivalent to `$argv[number]'.
       $*      Equivalent to `$argv', which is equivalent to `$argv[*]'.

       The `:' modifiers described under History substitution, except for `:p',
       can be applied to the substitutions above.  More than one may be used.
       (+) Braces may be needed to insulate a variable substitution from a
       literal colon just as with History substitution (q.v.); any modifiers
       must appear within the braces.

       The following substitutions can not be modified with `:' modifiers.

               Substitutes the string `1' if name is set, `0' if it is not.
       $?0     Substitutes `1' if the current input filename is known, `0' if it
               is not.  Always `0' in interactive shells.
               Substitutes the number of words in name.
       $#      Equivalent to `$#argv'.  (+)
               Substitutes the number of characters in name.  (+)
               Substitutes the number of characters in $argv[number].  (+)
       $?      Equivalent to `$status'.  (+)
       $$      Substitutes the (decimal) process number of the (parent) shell.
       $!      Substitutes the (decimal) process number of the last background
               process started by this shell.  (+)
       $_      Substitutes the command line of the last command executed.  (+)
       $<      Substitutes a line from the standard input, with no further
               interpretation thereafter.  It can be used to read from the
               keyboard in a shell script.  (+) While csh always quotes $<, as
               if it were equivalent to `$<:q', tcsh does not.  Furthermore,
               when tcsh is waiting for a line to be typed the user may type an
               interrupt to interrupt the sequence into which the line is to be
               substituted, but csh does not allow this.

       The editor command expand-variables, normally bound to `^X-$', can be
       used to interactively expand individual variables.

   Command, filename and directory stack substitution
       The remaining substitutions are applied selectively to the arguments of
       builtin commands.  This means that portions of expressions which are not
       evaluated are not subjected to these expansions.  For commands which are
       not internal to the shell, the command name is substituted separately
       from the argument list.  This occurs very late, after input-output
       redirection is performed, and in a child of the main shell.

   Command substitution
       Command substitution is indicated by a command enclosed in ``'.  The
       output from such a command is broken into separate words at blanks, tabs
       and newlines, and null words are discarded.  The output is variable and
       command substituted and put in place of the original string.

       Command substitutions inside double quotes (`"') retain blanks and tabs;
       only newlines force new words.  The single final newline does not force a
       new word in any case.  It is thus possible for a command substitution to
       yield only part of a word, even if the command outputs a complete line.

       By default, the shell since version 6.12 replaces all newline and
       carriage return characters in the command by spaces.  If this is switched
       off by unsetting csubstnonl, newlines separate commands as usual.

   Filename substitution
       If a word contains any of the characters `*', `?', `[' or `{' or begins
       with the character `~' it is a candidate for filename substitution, also
       known as ``globbing''.  This word is then regarded as a pattern (``glob-
       pattern''), and replaced with an alphabetically sorted list of file names
       which match the pattern.

       In matching filenames, the character `.' at the beginning of a filename
       or immediately following a `/', as well as the character `/' must be
       matched explicitly (unless either globdot or globstar or both are
       set(+)).  The character `*' matches any string of characters, including
       the null string.  The character `?' matches any single character.  The
       sequence `[...]' matches any one of the characters enclosed.  Within
       `[...]', a pair of characters separated by `-' matches any character
       lexically between the two.

       (+) Some glob-patterns can be negated: The sequence `[^...]' matches any
       single character not specified by the characters and/or ranges of
       characters in the braces.

       An entire glob-pattern can also be negated with `^':

           > echo *
           bang crash crunch ouch
           > echo ^cr*
           bang ouch

       Glob-patterns which do not use `?', `*', or `[]' or which use `{}' or `~'
       (below) are not negated correctly.

       The metanotation `a{b,c,d}e' is a shorthand for `abe ace ade'.  Left-to-
       right order is preserved: `/usr/source/s1/{oldls,ls}.c' expands to
       `/usr/source/s1/oldls.c /usr/source/s1/ls.c'.  The results of matches are
       sorted separately at a low level to preserve this order: `../{memo,*box}'
       might expand to `../memo ../box ../mbox'.  (Note that `memo' was not
       sorted with the results of matching `*box'.)  It is not an error when
       this construct expands to files which do not exist, but it is possible to
       get an error from a command to which the expanded list is passed.  This
       construct may be nested.  As a special case the words `{', `}' and `{}'
       are passed undisturbed.

       The character `~' at the beginning of a filename refers to home
       directories.  Standing alone, i.e., `~', it expands to the invoker's home
       directory as reflected in the value of the home shell variable.  When
       followed by a name consisting of letters, digits and `-' characters the
       shell searches for a user with that name and substitutes their home
       directory; thus `~ken' might expand to `/usr/ken' and `~ken/chmach' to
       `/usr/ken/chmach'.  If the character `~' is followed by a character other
       than a letter or `/' or appears elsewhere than at the beginning of a
       word, it is left undisturbed.  A command like `setenv MANPATH
       /usr/man:/usr/local/man:~/lib/man' does not, therefore, do home directory
       substitution as one might hope.

       It is an error for a glob-pattern containing `*', `?', `[' or `~', with
       or without `^', not to match any files.  However, only one pattern in a
       list of glob-patterns must match a file (so that, e.g., `rm *.a *.c *.o'
       would fail only if there were no files in the current directory ending in
       `.a', `.c', or `.o'), and if the nonomatch shell variable is set a
       pattern (or list of patterns) which matches nothing is left unchanged
       rather than causing an error.

       The globstar shell variable can be set to allow `**' or `***' as a file
       glob pattern that matches any string of characters including `/',
       recursively traversing any existing sub-directories.  For example, `ls
       **.c' will list all the .c files in the current directory tree.  If used
       by itself, it will match zero or more sub-directories (e.g. `ls
       /usr/include/**/time.h' will list any file named `time.h' in the
       /usr/include directory tree; `ls /usr/include/**time.h' will match any
       file in the /usr/include directory tree ending in `time.h'; and `ls
       /usr/include/**time**.h' will match any .h file with `time' either in a
       subdirectory name or in the filename itself).  To prevent problems with
       recursion, the `**' glob-pattern will not descend into a symbolic link
       containing a directory.  To override this, use `***' (+)

       The noglob shell variable can be set to prevent filename substitution,
       and the expand-glob editor command, normally bound to `^X-*', can be used
       to interactively expand individual filename substitutions.

   Directory stack substitution (+)
       The directory stack is a list of directories, numbered from zero, used by
       the pushd, popd and dirs builtin commands (q.v.).  dirs can print, store
       in a file, restore and clear the directory stack at any time, and the
       savedirs and dirsfile shell variables can be set to store the directory
       stack automatically on logout and restore it on login.  The dirstack
       shell variable can be examined to see the directory stack and set to put
       arbitrary directories into the directory stack.

       The character `=' followed by one or more digits expands to an entry in
       the directory stack.  The special case `=-' expands to the last directory
       in the stack.  For example,

           > dirs -v
           0       /usr/bin
           1       /usr/spool/uucp
           2       /usr/accts/sys
           > echo =1
           > echo =0/calendar
           > echo =-

       The noglob and nonomatch shell variables and the expand-glob editor
       command apply to directory stack as well as filename substitutions.

   Other substitutions (+)
       There are several more transformations involving filenames, not strictly
       related to the above but mentioned here for completeness.  Any filename
       may be expanded to a full path when the symlinks variable (q.v.) is set
       to `expand'.  Quoting prevents this expansion, and the normalize-path
       editor command does it on demand.  The normalize-command editor command
       expands commands in PATH into full paths on demand.  Finally, cd and
       pushd interpret `-' as the old working directory (equivalent to the shell
       variable owd).  This is not a substitution at all, but an abbreviation
       recognized by only those commands.  Nonetheless, it too can be prevented
       by quoting.

       The next three sections describe how the shell executes commands and
       deals with their input and output.

   Simple commands, pipelines and sequences
       A simple command is a sequence of words, the first of which specifies the
       command to be executed.  A series of simple commands joined by `|'
       characters forms a pipeline.  The output of each command in a pipeline is
       connected to the input of the next.

       Simple commands and pipelines may be joined into sequences with `;', and
       will be executed sequentially.  Commands and pipelines can also be joined
       into sequences with `||' or `&&', indicating, as in the C language, that
       the second is to be executed only if the first fails or succeeds

       A simple command, pipeline or sequence may be placed in parentheses,
       `()', to form a simple command, which may in turn be a component of a
       pipeline or sequence.  A command, pipeline or sequence can be executed
       without waiting for it to terminate by following it with an `&'.

   Builtin and non-builtin command execution
       Builtin commands are executed within the shell.  If any component of a
       pipeline except the last is a builtin command, the pipeline is executed
       in a subshell.

       Parenthesized commands are always executed in a subshell.

           (cd; pwd); pwd

       thus prints the home directory, leaving you where you were (printing this
       after the home directory), while

           cd; pwd

       leaves you in the home directory.  Parenthesized commands are most often
       used to prevent cd from affecting the current shell.

       When a command to be executed is found not to be a builtin command the
       shell attempts to execute the command via execve(2).  Each word in the
       variable path names a directory in which the shell will look for the
       command.  If the shell is not given a -f option, the shell hashes the
       names in these directories into an internal table so that it will try an
       execve(2) in only a directory where there is a possibility that the
       command resides there.  This greatly speeds command location when a large
       number of directories are present in the search path. This hashing
       mechanism is not used:

       1.  If hashing is turned explicitly off via unhash.

       2.  If the shell was given a -f argument.

       3.  For each directory component of path which does not begin with a `/'.

       4.  If the command contains a `/'.

       In the above four cases the shell concatenates each component of the path
       vector with the given command name to form a path name of a file which it
       then attempts to execute it. If execution is successful, the search

       If the file has execute permissions but is not an executable to the
       system (i.e., it is neither an executable binary nor a script that
       specifies its interpreter), then it is assumed to be a file containing
       shell commands and a new shell is spawned to read it.  The shell special
       alias may be set to specify an interpreter other than the shell itself.

       On systems which do not understand the `#!' script interpreter convention
       the shell may be compiled to emulate it; see the version shell variable.
       If so, the shell checks the first line of the file to see if it is of the
       form `#!interpreter arg ...'.  If it is, the shell starts interpreter
       with the given args and feeds the file to it on standard input.

       The standard input and standard output of a command may be redirected
       with the following syntax:

       < name  Open file name (which is first variable, command and filename
               expanded) as the standard input.
       << word Read the shell input up to a line which is identical to word.
               word is not subjected to variable, filename or command
               substitution, and each input line is compared to word before any
               substitutions are done on this input line.  Unless a quoting `\',
               `"', `' or ``' appears in word variable and command substitution
               is performed on the intervening lines, allowing `\' to quote `$',
               `\' and ``'.  Commands which are substituted have all blanks,
               tabs, and newlines preserved, except for the final newline which
               is dropped.  The resultant text is placed in an anonymous
               temporary file which is given to the command as standard input.
       > name
       >! name
       >& name
       >&! name
               The file name is used as standard output.  If the file does not
               exist then it is created; if the file exists, it is truncated,
               its previous contents being lost.

               If the shell variable noclobber is set, then the file must not
               exist or be a character special file (e.g., a terminal or
               `/dev/null') or an error results.  This helps prevent accidental
               destruction of files.  In this case the `!' forms can be used to
               suppress this check.  If notempty is given in noclobber, `>' is
               allowed on empty files; if ask is set, an interacive confirmation
               is presented, rather than an error.

               The forms involving `&' route the diagnostic output into the
               specified file as well as the standard output.  name is expanded
               in the same way as `<' input filenames are.
       >> name
       >>& name
       >>! name
       >>&! name
               Like `>', but appends output to the end of name.  If the shell
               variable noclobber is set, then it is an error for the file not
               to exist, unless one of the `!' forms is given.

       A command receives the environment in which the shell was invoked as
       modified by the input-output parameters and the presence of the command
       in a pipeline.  Thus, unlike some previous shells, commands run from a
       file of shell commands have no access to the text of the commands by
       default; rather they receive the original standard input of the shell.
       The `<<' mechanism should be used to present inline data.  This permits
       shell command scripts to function as components of pipelines and allows
       the shell to block read its input.  Note that the default standard input
       for a command run detached is not the empty file /dev/null, but the
       original standard input of the shell.  If this is a terminal and if the
       process attempts to read from the terminal, then the process will block
       and the user will be notified (see Jobs).

       Diagnostic output may be directed through a pipe with the standard
       output.  Simply use the form `|&' rather than just `|'.

       The shell cannot presently redirect diagnostic output without also
       redirecting standard output, but `(command > output-file) >& error-file'
       is often an acceptable workaround.  Either output-file or error-file may
       be `/dev/tty' to send output to the terminal.

       Having described how the shell accepts, parses and executes command
       lines, we now turn to a variety of its useful features.

   Control flow
       The shell contains a number of commands which can be used to regulate the
       flow of control in command files (shell scripts) and (in limited but
       useful ways) from terminal input.  These commands all operate by forcing
       the shell to reread or skip in its input and, due to the implementation,
       restrict the placement of some of the commands.

       The foreach, switch, and while statements, as well as the if-then-else
       form of the if statement, require that the major keywords appear in a
       single simple command on an input line as shown below.

       If the shell's input is not seekable, the shell buffers up input whenever
       a loop is being read and performs seeks in this internal buffer to
       accomplish the rereading implied by the loop.  (To the extent that this
       allows, backward gotos will succeed on non-seekable inputs.)

       The if, while and exit builtin commands use expressions with a common
       syntax.  The expressions can include any of the operators described in
       the next three sections.  Note that the @ builtin command (q.v.) has its
       own separate syntax.

   Logical, arithmetical and comparison operators
       These operators are similar to those of C and have the same precedence.
       They include

           ||  &&  |  ^  &  ==  !=  =~  !~  <=  >=
           <  > <<  >>  +  -  *  /  %  !  ~  (  )

       Here the precedence increases to the right, `==' `!=' `=~' and `!~', `<='
       `>=' `<' and `>', `<<' and `>>', `+' and `-', `*' `/' and `%' being, in
       groups, at the same level.  The `==' `!=' `=~' and `!~' operators compare
       their arguments as strings; all others operate on numbers.  The operators
       `=~' and `!~' are like `!=' and `==' except that the right hand side is a
       glob-pattern (see Filename substitution) against which the left hand
       operand is matched.  This reduces the need for use of the switch builtin
       command in shell scripts when all that is really needed is pattern

       Null or missing arguments are considered `0'.  The results of all
       expressions are strings, which represent decimal numbers.  It is
       important to note that no two components of an expression can appear in
       the same word; except when adjacent to components of expressions which
       are syntactically significant to the parser (`&' `|' `<' `>' `(' `)')
       they should be surrounded by spaces.

   Command exit status
       Commands can be executed in expressions and their exit status returned by
       enclosing them in braces (`{}').  Remember that the braces should be
       separated from the words of the command by spaces.  Command executions
       succeed, returning true, i.e., `1', if the command exits with status 0,
       otherwise they fail, returning false, i.e., `0'.  If more detailed status
       information is required then the command should be executed outside of an
       expression and the status shell variable examined.

   File inquiry operators
       Some of these operators perform true/false tests on files and related
       objects.  They are of the form -op file, where op is one of

           r   Read access
           w   Write access
           x   Execute access
           X   Executable in the path or shell builtin, e.g., `-X ls' and `-X
               ls-F' are generally true, but `-X /bin/ls' is not (+)
           e   Existence
           o   Ownership
           z   Zero size
           s   Non-zero size (+)
           f   Plain file
           d   Directory
           l   Symbolic link (+) *
           b   Block special file (+)
           c   Character special file (+)
           p   Named pipe (fifo) (+) *
           S   Socket special file (+) *
           u   Set-user-ID bit is set (+)
           g   Set-group-ID bit is set (+)
           k   Sticky bit is set (+)
           t   file (which must be a digit) is an open file descriptor for a
               terminal device (+)
           R   Has been migrated (Convex only) (+)
           L   Applies subsequent operators in a multiple-operator test to a
               symbolic link rather than to the file to which the link points
               (+) *

       file is command and filename expanded and then tested to see if it has
       the specified relationship to the real user.  If file does not exist or
       is inaccessible or, for the operators indicated by `*', if the specified
       file type does not exist on the current system, then all inquiries return
       false, i.e., `0'.

       These operators may be combined for conciseness: `-xy file' is equivalent
       to `-x file && -y file'.  (+) For example, `-fx' is true (returns `1')
       for plain executable files, but not for directories.

       L may be used in a multiple-operator test to apply subsequent operators
       to a symbolic link rather than to the file to which the link points.  For
       example, `-lLo' is true for links owned by the invoking user.  Lr, Lw and
       Lx are always true for links and false for non-links.  L has a different
       meaning when it is the last operator in a multiple-operator test; see

       It is possible but not useful, and sometimes misleading, to combine
       operators which expect file to be a file with operators which do not
       (e.g., X and t).  Following L with a non-file operator can lead to
       particularly strange results.

       Other operators return other information, i.e., not just `0' or `1'.  (+)
       They have the same format as before; op may be one of

           A       Last file access time, as the number of seconds since the
           A:      Like A, but in timestamp format, e.g., `Fri May 14 16:36:10
           M       Last file modification time
           M:      Like M, but in timestamp format
           C       Last inode modification time
           C:      Like C, but in timestamp format
           D       Device number
           I       Inode number
           F       Composite file identifier, in the form device:inode
           L       The name of the file pointed to by a symbolic link
           N       Number of (hard) links
           P       Permissions, in octal, without leading zero
           P:      Like P, with leading zero
           Pmode   Equivalent to `-P file & mode', e.g., `-P22 file' returns
                   `22' if file is writable by group and other, `20' if by group
                   only, and `0' if by neither
           Pmode:  Like Pmode, with leading zero
           U       Numeric userid
           U:      Username, or the numeric userid if the username is unknown
           G       Numeric groupid
           G:      Groupname, or the numeric groupid if the groupname is unknown
           Z       Size, in bytes

       Only one of these operators may appear in a multiple-operator test, and
       it must be the last.  Note that L has a different meaning at the end of
       and elsewhere in a multiple-operator test.  Because `0' is a valid return
       value for many of these operators, they do not return `0' when they fail:
       most return `-1', and F returns `:'.

       If the shell is compiled with POSIX defined (see the version shell
       variable), the result of a file inquiry is based on the permission bits
       of the file and not on the result of the access(2) system call.  For
       example, if one tests a file with -w whose permissions would ordinarily
       allow writing but which is on a file system mounted read-only, the test
       will succeed in a POSIX shell but fail in a non-POSIX shell.

       File inquiry operators can also be evaluated with the filetest builtin
       command (q.v.) (+).

       The shell associates a job with each pipeline.  It keeps a table of
       current jobs, printed by the jobs command, and assigns them small integer
       numbers.  When a job is started asynchronously with `&', the shell prints
       a line which looks like

           [1] 1234

       indicating that the job which was started asynchronously was job number 1
       and had one (top-level) process, whose process id was 1234.

       If you are running a job and wish to do something else you may hit the
       suspend key (usually `^Z'), which sends a STOP signal to the current job.
       The shell will then normally indicate that the job has been `Suspended'
       and print another prompt.  If the listjobs shell variable is set, all
       jobs will be listed like the jobs builtin command; if it is set to `long'
       the listing will be in long format, like `jobs -l'.  You can then
       manipulate the state of the suspended job.  You can put it in the
       ``background'' with the bg command or run some other commands and
       eventually bring the job back into the ``foreground'' with fg.  (See also
       the run-fg-editor editor command.)  A `^Z' takes effect immediately and
       is like an interrupt in that pending output and unread input are
       discarded when it is typed.  The wait builtin command causes the shell to
       wait for all background jobs to complete.

       The `^]' key sends a delayed suspend signal, which does not generate a
       STOP signal until a program attempts to read(2) it, to the current job.
       This can usefully be typed ahead when you have prepared some commands for
       a job which you wish to stop after it has read them.  The `^Y' key
       performs this function in csh(1); in tcsh, `^Y' is an editing command.

       A job being run in the background stops if it tries to read from the
       terminal.  Background jobs are normally allowed to produce output, but
       this can be disabled by giving the command `stty tostop'.  If you set
       this tty option, then background jobs will stop when they try to produce
       output like they do when they try to read input.

       There are several ways to refer to jobs in the shell.  The character `%'
       introduces a job name.  If you wish to refer to job number 1, you can
       name it as `%1'.  Just naming a job brings it to the foreground; thus
       `%1' is a synonym for `fg %1', bringing job 1 back into the foreground.
       Similarly, saying `%1 &' resumes job 1 in the background, just like `bg
       %1'.  A job can also be named by an unambiguous prefix of the string
       typed in to start it: `%ex' would normally restart a suspended ex(1) job,
       if there were only one suspended job whose name began with the string
       `ex'.  It is also possible to say `%?string' to specify a job whose text
       contains string, if there is only one such job.

       The shell maintains a notion of the current and previous jobs.  In output
       pertaining to jobs, the current job is marked with a `+' and the previous
       job with a `-'.  The abbreviations `%+', `%', and (by analogy with the
       syntax of the history mechanism) `%%' all refer to the current job, and
       `%-' refers to the previous job.

       The job control mechanism requires that the stty(1) option `new' be set
       on some systems.  It is an artifact from a `new' implementation of the
       tty driver which allows generation of interrupt characters from the
       keyboard to tell jobs to stop.  See stty(1) and the setty builtin command
       for details on setting options in the new tty driver.

   Status reporting
       The shell learns immediately whenever a process changes state.  It
       normally informs you whenever a job becomes blocked so that no further
       progress is possible, but only right before it prints a prompt.  This is
       done so that it does not otherwise disturb your work.  If, however, you
       set the shell variable notify, the shell will notify you immediately of
       changes of status in background jobs.  There is also a shell command
       notify which marks a single process so that its status changes will be
       immediately reported.  By default notify marks the current process;
       simply say `notify' after starting a background job to mark it.

       When you try to leave the shell while jobs are stopped, you will be
       warned that `There are suspended jobs.' You may use the jobs command to
       see what they are.  If you do this or immediately try to exit again, the
       shell will not warn you a second time, and the suspended jobs will be

   Automatic, periodic and timed events (+)
       There are various ways to run commands and take other actions
       automatically at various times in the ``life cycle'' of the shell.  They
       are summarized here, and described in detail under the appropriate
       Builtin commands, Special shell variables and Special aliases.

       The sched builtin command puts commands in a scheduled-event list, to be
       executed by the shell at a given time.

       The beepcmd, cwdcmd, periodic, precmd, postcmd, and jobcmd Special
       aliases can be set, respectively, to execute commands when the shell
       wants to ring the bell, when the working directory changes, every tperiod
       minutes, before each prompt, before each command gets executed, after
       each command gets executed, and when a job is started or is brought into
       the foreground.

       The autologout shell variable can be set to log out or lock the shell
       after a given number of minutes of inactivity.

       The mail shell variable can be set to check for new mail periodically.

       The printexitvalue shell variable can be set to print the exit status of
       commands which exit with a status other than zero.

       The rmstar shell variable can be set to ask the user, when `rm *' is
       typed, if that is really what was meant.

       The time shell variable can be set to execute the time builtin command
       after the completion of any process that takes more than a given number
       of CPU seconds.

       The watch and who shell variables can be set to report when selected
       users log in or out, and the log builtin command reports on those users
       at any time.

   Native Language System support (+)
       The shell is eight bit clean (if so compiled; see the version shell
       variable) and thus supports character sets needing this capability.  NLS
       support differs depending on whether or not the shell was compiled to use
       the system's NLS (again, see version).  In either case, 7-bit ASCII is
       the default character code (e.g., the classification of which characters
       are printable) and sorting, and changing the LANG or LC_CTYPE environment
       variables causes a check for possible changes in these respects.

       When using the system's NLS, the setlocale(3) function is called to
       determine appropriate character code/classification and sorting (e.g., a
       'en_CA.UTF-8' would yield "UTF-8" as a character code).  This function
       typically examines the LANG and LC_CTYPE environment variables; refer to
       the system documentation for further details.  When not using the
       system's NLS, the shell simulates it by assuming that the ISO 8859-1
       character set is used whenever either of the LANG and LC_CTYPE variables
       are set, regardless of their values.  Sorting is not affected for the
       simulated NLS.

       In addition, with both real and simulated NLS, all printable characters
       in the range \200-\377, i.e., those that have M-char bindings, are
       automatically rebound to self-insert-command.  The corresponding binding
       for the escape-char sequence, if any, is left alone.  These characters
       are not rebound if the NOREBIND environment variable is set.  This may be
       useful for the simulated NLS or a primitive real NLS which assumes full
       ISO 8859-1.  Otherwise, all M-char bindings in the range \240-\377 are
       effectively undone.  Explicitly rebinding the relevant keys with bindkey
       is of course still possible.

       Unknown characters (i.e., those that are neither printable nor control
       characters) are printed in the format \nnn.  If the tty is not in 8 bit
       mode, other 8 bit characters are printed by converting them to ASCII and
       using standout mode.  The shell never changes the 7/8 bit mode of the tty
       and tracks user-initiated changes of 7/8 bit mode.  NLS users (or, for
       that matter, those who want to use a meta key) may need to explicitly set
       the tty in 8 bit mode through the appropriate stty(1) command in, e.g.,
       the ~/.login file.

   OS variant support (+)
       A number of new builtin commands are provided to support features in
       particular operating systems.  All are described in detail in the Builtin
       commands section.

       On systems that support TCF (aix-ibm370, aix-ps2), getspath and setspath
       get and set the system execution path, getxvers and setxvers get and set
       the experimental version prefix and migrate migrates processes between
       sites.  The jobs builtin prints the site on which each job is executing.

       Under BS2000, bs2cmd executes commands of the underlying BS2000/OSD
       operating system.

       Under Domain/OS, inlib adds shared libraries to the current environment,
       rootnode changes the rootnode and ver changes the systype.

       Under Mach, setpath is equivalent to Mach's setpath(1).

       Under Masscomp/RTU and Harris CX/UX, universe sets the universe.

       Under Harris CX/UX, ucb or att runs a command under the specified

       Under Convex/OS, warp prints or sets the universe.

       The VENDOR, OSTYPE and MACHTYPE environment variables indicate
       respectively the vendor, operating system and machine type
       (microprocessor class or machine model) of the system on which the shell
       thinks it is running.  These are particularly useful when sharing one's
       home directory between several types of machines; one can, for example,

           set path = (~/bin.$MACHTYPE /usr/ucb /bin /usr/bin .)

       in one's ~/.login and put executables compiled for each machine in the
       appropriate directory.

       The version shell variable indicates what options were chosen when the
       shell was compiled.

       Note also the newgrp builtin, the afsuser and echo_style shell variables
       and the system-dependent locations of the shell's input files (see

   Signal handling
       Login shells ignore interrupts when reading the file ~/.logout.  The
       shell ignores quit signals unless started with -q.  Login shells catch
       the terminate signal, but non-login shells inherit the terminate behavior
       from their parents.  Other signals have the values which the shell
       inherited from its parent.

       In shell scripts, the shell's handling of interrupt and terminate signals
       can be controlled with onintr, and its handling of hangups can be
       controlled with hup and nohup.

       The shell exits on a hangup (see also the logout shell variable).  By
       default, the shell's children do too, but the shell does not send them a
       hangup when it exits.  hup arranges for the shell to send a hangup to a
       child when it exits, and nohup sets a child to ignore hangups.

   Terminal management (+)
       The shell uses three different sets of terminal (``tty'') modes: `edit',
       used when editing, `quote', used when quoting literal characters, and
       `execute', used when executing commands.  The shell holds some settings
       in each mode constant, so commands which leave the tty in a confused
       state do not interfere with the shell.  The shell also matches changes in
       the speed and padding of the tty.  The list of tty modes that are kept
       constant can be examined and modified with the setty builtin.  Note that
       although the editor uses CBREAK mode (or its equivalent), it takes typed-
       ahead characters anyway.

       The echotc, settc and telltc commands can be used to manipulate and debug
       terminal capabilities from the command line.

       On systems that support SIGWINCH or SIGWINDOW, the shell adapts to window
       resizing automatically and adjusts the environment variables LINES and
       COLUMNS if set.  If the environment variable TERMCAP contains li# and co#
       fields, the shell adjusts them to reflect the new window size.

       The next sections of this manual describe all of the available Builtin
       commands, Special aliases and Special shell variables.

   Builtin commands
       %job    A synonym for the fg builtin command.

       %job &  A synonym for the bg builtin command.

       :       Does nothing, successfully.

       @ name = expr
       @ name[index] = expr
       @ name++|--
       @ name[index]++|--
               The first form prints the values of all shell variables.

               The second form assigns the value of expr to name.  The third
               form assigns the value of expr to the index'th component of name;
               both name and its index'th component must already exist.

               expr may contain the operators `*', `+', etc., as in C.  If expr
               contains `<', `>', `&' or `' then at least that part of expr must
               be placed within `()'.  Note that the syntax of expr has nothing
               to do with that described under Expressions.

               The fourth and fifth forms increment (`++') or decrement (`--')
               name or its index'th component.

               The space between `@' and name is required.  The spaces between
               name and `=' and between `=' and expr are optional.  Components
               of expr must be separated by spaces.

       alias [name [wordlist]]
               Without arguments, prints all aliases.  With name, prints the
               alias for name.  With name and wordlist, assigns wordlist as the
               alias of name.  wordlist is command and filename substituted.
               name may not be `alias' or `unalias'.  See also the unalias
               builtin command.

       alloc   Shows the amount of dynamic memory acquired, broken down into
               used and free memory.  With an argument shows the number of free
               and used blocks in each size category.  The categories start at
               size 8 and double at each step.  This command's output may vary
               across system types, because systems other than the VAX may use a
               different memory allocator.

       bg [%job ...]
               Puts the specified jobs (or, without arguments, the current job)
               into the background, continuing each if it is stopped.  job may
               be a number, a string, `', `%', `+' or `-' as described under

       bindkey [-l|-d|-e|-v|-u] (+)
       bindkey [-a] [-b] [-k] [-r] [--] key (+)
       bindkey [-a] [-b] [-k] [-c|-s] [--] key command (+)
               Without options, the first form lists all bound keys and the
               editor command to which each is bound, the second form lists the
               editor command to which key is bound and the third form binds the
               editor command command to key.  Options include:

               -l  Lists all editor commands and a short description of each.
               -d  Binds all keys to the standard bindings for the default
                   editor, as per -e and -v below.
               -e  Binds all keys to emacs(1)-style bindings.  Unsets vimode.
               -v  Binds all keys to vi(1)-style bindings.  Sets vimode.
               -a  Lists or changes key-bindings in the alternative key map.
                   This is the key map used in vimode command mode.
               -b  key is interpreted as a control character written ^character
                   (e.g., `^A') or C-character (e.g., `C-A'), a meta character
                   written M-character (e.g., `M-A'), a function key written
                   F-string (e.g., `F-string'), or an extended prefix key
                   written X-character (e.g., `X-A').
               -k  key is interpreted as a symbolic arrow key name, which may be
                   one of `down', `up', `left' or `right'.
               -r  Removes key's binding.  Be careful: `bindkey -r' does not
                   bind key to self-insert-command (q.v.), it unbinds key
               -c  command is interpreted as a builtin or external command
                   instead of an editor command.
               -s  command is taken as a literal string and treated as terminal
                   input when key is typed.  Bound keys in command are
                   themselves reinterpreted, and this continues for ten levels
                   of interpretation.
               --  Forces a break from option processing, so the next word is
                   taken as key even if it begins with '-'.
               -u (or any invalid option)
                   Prints a usage message.

               key may be a single character or a string.  If a command is bound
               to a string, the first character of the string is bound to
               sequence-lead-in and the entire string is bound to the command.

               Control characters in key can be literal (they can be typed by
               preceding them with the editor command quoted-insert, normally
               bound to `^V') or written caret-character style, e.g., `^A'.
               Delete is written `^?' (caret-question mark).  key and command
               can contain backslashed escape sequences (in the style of System
               V echo(1)) as follows:

                   \a      Bell
                   \b      Backspace
                   \e      Escape
                   \f      Form feed
                   \n      Newline
                   \r      Carriage return
                   \t      Horizontal tab
                   \v      Vertical tab
                   \nnn    The ASCII character corresponding to the octal number

               `\' nullifies the special meaning of the following character, if
               it has any, notably `\' and `^'.

       bs2cmd bs2000-command (+)
               Passes bs2000-command to the BS2000 command interpreter for
               execution. Only non-interactive commands can be executed, and it
               is not possible to execute any command that would overlay the
               image of the current process, like /EXECUTE or /CALL-PROCEDURE.
               (BS2000 only)

       break   Causes execution to resume after the end of the nearest enclosing
               foreach or while.  The remaining commands on the current line are
               executed.  Multi-level breaks are thus possible by writing them
               all on one line.

       breaksw Causes a break from a switch, resuming after the endsw.

       builtins (+)
               Prints the names of all builtin commands.

       bye (+) A synonym for the logout builtin command.  Available only if the
               shell was so compiled; see the version shell variable.

       case label:
               A label in a switch statement as discussed below.

       cd [-p] [-l] [-n|-v] [I--] [name]
               If a directory name is given, changes the shell's working
               directory to name.  If not, changes to home, unless the cdtohome
               variable is not set, in which case a name is required.  If name
               is `-' it is interpreted as the previous working directory (see
               Other substitutions).  (+) If name is not a subdirectory of the
               current directory (and does not begin with `/', `./' or `../'),
               each component of the variable cdpath is checked to see if it has
               a subdirectory name.  Finally, if all else fails but name is a
               shell variable whose value begins with `/' or '.', then this is
               tried to see if it is a directory, and the -p option is implied.

               With -p, prints the final directory stack, just like dirs.  The
               -l, -n and -v flags have the same effect on cd as on dirs, and
               they imply -p.  (+) Using -- forces a break from option
               processing so the next word is taken as the directory name even
               if it begins with '-'. (+)

               See also the implicitcd and cdtohome shell variables.

       chdir   A synonym for the cd builtin command.

       complete [command [word/pattern/list[:select]/[[suffix]/] ...]] (+)
               Without arguments, lists all completions.  With command, lists
               completions for command.  With command and word etc., defines

               command may be a full command name or a glob-pattern (see
               Filename substitution).  It can begin with `-' to indicate that
               completion should be used only when command is ambiguous.

               word specifies which word relative to the current word is to be
               completed, and may be one of the following:

                   c   Current-word completion.  pattern is a glob-pattern which
                       must match the beginning of the current word on the
                       command line.  pattern is ignored when completing the
                       current word.
                   C   Like c, but includes pattern when completing the current
                   n   Next-word completion.  pattern is a glob-pattern which
                       must match the beginning of the previous word on the
                       command line.
                   N   Like n, but must match the beginning of the word two
                       before the current word.
                   p   Position-dependent completion.  pattern is a numeric
                       range, with the same syntax used to index shell
                       variables, which must include the current word.

               list, the list of possible completions, may be one of the

                   a       Aliases
                   b       Bindings (editor commands)
                   c       Commands (builtin or external commands)
                   C       External commands which begin with the supplied path
                   d       Directories
                   D       Directories which begin with the supplied path prefix
                   e       Environment variables
                   f       Filenames
                   F       Filenames which begin with the supplied path prefix
                   g       Groupnames
                   j       Jobs
                   l       Limits
                   n       Nothing
                   s       Shell variables
                   S       Signals
                   t       Plain (``text'') files
                   T       Plain (``text'') files which begin with the supplied
                           path prefix
                   v       Any variables
                   u       Usernames
                   x       Like n, but prints select when list-choices is used.
                   X       Completions
                   $var    Words from the variable var
                   (...)   Words from the given list
                   `...`   Words from the output of command

               select is an optional glob-pattern.  If given, words from only
               list that match select are considered and the fignore shell
               variable is ignored.  The last three types of completion may not
               have a select pattern, and x uses select as an explanatory
               message when the list-choices editor command is used.

               suffix is a single character to be appended to a successful
               completion.  If null, no character is appended.  If omitted (in
               which case the fourth delimiter can also be omitted), a slash is
               appended to directories and a space to other words.

               command invoked from `...` version has additional environment
               variable set, the variable name is COMMAND_LINE and contains (as
               its name indicates) contents of the current (already typed in)
               command line. One can examine and use contents of the
               COMMAND_LINE variable in her custom script to build more
               sophisticated completions (see completion for svn(1) included in
               this package).

               Now for some examples.  Some commands take only directories as
               arguments, so there's no point completing plain files.

                   > complete cd 'p/1/d/'

               completes only the first word following `cd' (`p/1') with a
               directory.  p-type completion can also be used to narrow down
               command completion:

                   > co[^D]
                   complete compress
                   > complete -co* 'p/0/(compress)/'
                   > co[^D]
                   > compress

               This completion completes commands (words in position 0, `p/0')
               which begin with `co' (thus matching `co*') to `compress' (the
               only word in the list).  The leading `-' indicates that this
               completion is to be used with only ambiguous commands.

                   > complete find 'n/-user/u/'

               is an example of n-type completion.  Any word following `find'
               and immediately following `-user' is completed from the list of

                   > complete cc 'c/-I/d/'

               demonstrates c-type completion.  Any word following `cc' and
               beginning with `-I' is completed as a directory.  `-I' is not
               taken as part of the directory because we used lowercase c.

               Different lists are useful with different commands.

                   > complete alias 'p/1/a/'
                   > complete man 'p/*/c/'
                   > complete set 'p/1/s/'
                   > complete true 'p/1/x:Truth has no options./'

               These complete words following `alias' with aliases, `man' with
               commands, and `set' with shell variables.  `true' doesn't have
               any options, so x does nothing when completion is attempted and
               prints `Truth has no options.' when completion choices are

               Note that the man example, and several other examples below,
               could just as well have used 'c/*' or 'n/*' as 'p/*'.

               Words can be completed from a variable evaluated at completion

                   > complete ftp 'p/1/$hostnames/'
                   > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu)
                   > ftp [^D]
                   rtfm.mit.edu tesla.ee.cornell.edu
                   > ftp [^C]
                   > set hostnames = (rtfm.mit.edu tesla.ee.cornell.edu
                   > ftp [^D]
                   rtfm.mit.edu tesla.ee.cornell.edu uunet.uu.net

               or from a command run at completion time:

                   > complete kill 'p/*/`ps | awk \{print\ \$1\}`/'
                   > kill -9 [^D]
                   23113 23377 23380 23406 23429 23529 23530 PID

               Note that the complete command does not itself quote its
               arguments, so the braces, space and `$' in `{print $1}' must be
               quoted explicitly.

               One command can have multiple completions:

                   > complete dbx 'p/2/(core)/' 'p/*/c/'

               completes the second argument to `dbx' with the word `core' and
               all other arguments with commands.  Note that the positional
               completion is specified before the next-word completion.  Because
               completions are evaluated from left to right, if the next-word
               completion were specified first it would always match and the
               positional completion would never be executed.  This is a common
               mistake when defining a completion.

               The select pattern is useful when a command takes files with only
               particular forms as arguments.  For example,

                   > complete cc 'p/*/f:*.[cao]/'

               completes `cc' arguments to files ending in only `.c', `.a', or
               `.o'.  select can also exclude files, using negation of a glob-
               pattern as described under Filename substitution.  One might use

                   > complete rm 'p/*/f:^*.{c,h,cc,C,tex,1,man,l,y}/'

               to exclude precious source code from `rm' completion.  Of course,
               one could still type excluded names manually or override the
               completion mechanism using the complete-word-raw or list-choices-
               raw editor commands (q.v.).

               The `C', `D', `F' and `T' lists are like `c', `d', `f' and `t'
               respectively, but they use the select argument in a different
               way: to restrict completion to files beginning with a particular
               path prefix.  For example, the Elm mail program uses `=' as an
               abbreviation for one's mail directory.  One might use

                   > complete elm c@=@F:$HOME/Mail/@

               to complete `elm -f =' as if it were `elm -f ~/Mail/'.  Note that
               we used `@' instead of `/' to avoid confusion with the select
               argument, and we used `$HOME' instead of `~' because home
               directory substitution works at only the beginning of a word.

               suffix is used to add a nonstandard suffix (not space or `/' for
               directories) to completed words.

                   > complete finger 'c/*@/$hostnames/' 'p/1/u/@'

               completes arguments to `finger' from the list of users, appends
               an `@', and then completes after the `@' from the `hostnames'
               variable.  Note again the order in which the completions are

               Finally, here's a complex example for inspiration:

                   > complete find \
                   'n/-name/f/' 'n/-newer/f/' 'n/-{,n}cpio/f/' \
                   ´n/-exec/c/' 'n/-ok/c/' 'n/-user/u/' \
                   'n/-group/g/' 'n/-fstype/(nfs 4.2)/' \
                   'n/-type/(b c d f l p s)/' \
                   ´c/-/(name newer cpio ncpio exec ok user \
                   group fstype type atime ctime depth inum \
                   ls mtime nogroup nouser perm print prune \
                   size xdev)/' \

               This completes words following `-name', `-newer', `-cpio' or
               `ncpio' (note the pattern which matches both) to files, words
               following `-exec' or `-ok' to commands, words following `user'
               and `group' to users and groups respectively and words following
               `-fstype' or `-type' to members of the given lists.  It also
               completes the switches themselves from the given list (note the
               use of c-type completion) and completes anything not otherwise
               completed to a directory.  Whew.

               Remember that programmed completions are ignored if the word
               being completed is a tilde substitution (beginning with `~') or a
               variable (beginning with `$').  See also the uncomplete builtin

               Continues execution of the nearest enclosing while or foreach.
               The rest of the commands on the current line are executed.

               Labels the default case in a switch statement.  It should come
               after all case labels.

       dirs [-l] [-n|-v]
       dirs -S|-L [filename] (+)
       dirs -c (+)
               The first form prints the directory stack.  The top of the stack
               is at the left and the first directory in the stack is the
               current directory.  With -l, `~' or `~name' in the output is
               expanded explicitly to home or the pathname of the home directory
               for user name.  (+) With -n, entries are wrapped before they
               reach the edge of the screen.  (+) With -v, entries are printed
               one per line, preceded by their stack positions.  (+) If more
               than one of -n or -v is given, -v takes precedence.  -p is
               accepted but does nothing.

               With -S, the second form saves the directory stack to filename as
               a series of cd and pushd commands.  With -L, the shell sources
               filename, which is presumably a directory stack file saved by the
               -S option or the savedirs mechanism.  In either case, dirsfile is
               used if filename is not given and ~/.cshdirs is used if dirsfile
               is unset.

               Note that login shells do the equivalent of `dirs -L' on startup
               and, if savedirs is set, `dirs -S' before exiting.  Because only
               ~/.tcshrc is normally sourced before ~/.cshdirs, dirsfile should
               be set in ~/.tcshrc rather than ~/.login.

               The last form clears the directory stack.

       echo [-n] word ...
               Writes each word to the shell's standard output, separated by
               spaces and terminated with a newline.  The echo_style shell
               variable may be set to emulate (or not) the flags and escape
               sequences of the BSD and/or System V versions of echo; see

       echotc [-sv] arg ... (+)
               Exercises the terminal capabilities (see termcap(5)) in args.
               For example, 'echotc home' sends the cursor to the home position,
               'echotc cm 3 10' sends it to column 3 and row 10, and 'echotc ts
               0; echo "This is a test."; echotc fs' prints "This is a test."
               in the status line.

               If arg is 'baud', 'cols', 'lines', 'meta' or 'tabs', prints the
               value of that capability ("yes" or "no" indicating that the
               terminal does or does not have that capability).  One might use
               this to make the output from a shell script less verbose on slow
               terminals, or limit command output to the number of lines on the

                   > set history=`echotc lines`
                   > @ history--

               Termcap strings may contain wildcards which will not echo
               correctly.  One should use double quotes when setting a shell
               variable to a terminal capability string, as in the following
               example that places the date in the status line:

                   > set tosl="`echotc ts 0`"
                   > set frsl="`echotc fs`"
                   > echo -n "$tosl";date; echo -n "$frsl"

               With -s, nonexistent capabilities return the empty string rather
               than causing an error.  With -v, messages are verbose.

       endsw   See the description of the foreach, if, switch, and while
               statements below.

       eval arg ...
               Treats the arguments as input to the shell and executes the
               resulting command(s) in the context of the current shell.  This
               is usually used to execute commands generated as the result of
               command or variable substitution, because parsing occurs before
               these substitutions.  See tset(1) for a sample use of eval.

       exec command
               Executes the specified command in place of the current shell.

       exit [expr]
               The shell exits either with the value of the specified expr (an
               expression, as described under Expressions) or, without expr,
               with the value 0.

       fg [%job ...]
               Brings the specified jobs (or, without arguments, the current
               job) into the foreground, continuing each if it is stopped.  job
               may be a number, a string, `', `%', `+' or `-' as described under
               Jobs.  See also the run-fg-editor editor command.

       filetest -op file ... (+)
               Applies op (which is a file inquiry operator as described under
               File inquiry operators) to each file and returns the results as a
               space-separated list.

       foreach name (wordlist)
       end     Successively sets the variable name to each member of wordlist
               and executes the sequence of commands between this command and
               the matching end.  (Both foreach and end must appear alone on
               separate lines.)  The builtin command continue may be used to
               continue the loop prematurely and the builtin command break to
               terminate it prematurely.  When this command is read from the
               terminal, the loop is read once prompting with `foreach? ' (or
               prompt2) before any statements in the loop are executed.  If you
               make a mistake typing in a loop at the terminal you can rub it

       getspath (+)
               Prints the system execution path.  (TCF only)

       getxvers (+)
               Prints the experimental version prefix.  (TCF only)

       glob wordlist
               Like echo, but the `-n' parameter is not recognized and words are
               delimited by null characters in the output.  Useful for programs
               which wish to use the shell to filename expand a list of words.

       goto word
               word is filename and command-substituted to yield a string of the
               form `label'.  The shell rewinds its input as much as possible,
               searches for a line of the form `label:', possibly preceded by
               blanks or tabs, and continues execution after that line.

               Prints a statistics line indicating how effective the internal
               hash table has been at locating commands (and avoiding exec's).
               An exec is attempted for each component of the path where the
               hash function indicates a possible hit, and in each component
               which does not begin with a `/'.

               On machines without vfork(2), prints only the number and size of
               hash buckets.

       history [-hTr] [n]
       history -S|-L|-M [filename] (+)
       history -c (+)
               The first form prints the history event list.  If n is given only
               the n most recent events are printed or saved.  With -h, the
               history list is printed without leading numbers.  If -T is
               specified, timestamps are printed also in comment form.  (This
               can be used to produce files suitable for loading with 'history
               -L' or 'source -h'.)  With -r, the order of printing is most
               recent first rather than oldest first.

               With -S, the second form saves the history list to filename.  If
               the first word of the savehist shell variable is set to a number,
               at most that many lines are saved.  If the second word of
               savehist is set to `merge', the history list is merged with the
               existing history file instead of replacing it (if there is one)
               and sorted by time stamp.  (+) Merging is intended for an
               environment like the X Window System with several shells in
               simultaneous use.  If the second word of savehist is `merge' and
               the third word is set to `lock', the history file update will be
               serialized with other shell sessions that would possibly like to
               merge history at exactly the same time.

               With -L, the shell appends filename, which is presumably a
               history list saved by the -S option or the savehist mechanism, to
               the history list.  -M is like -L, but the contents of filename
               are merged into the history list and sorted by timestamp.  In
               either case, histfile is used if filename is not given and
               ~/.history is used if histfile is unset.  `history -L' is exactly
               like 'source -h' except that it does not require a filename.

               Note that login shells do the equivalent of `history -L' on
               startup and, if savehist is set, `history -S' before exiting.
               Because only ~/.tcshrc is normally sourced before ~/.history,
               histfile should be set in ~/.tcshrc rather than ~/.login.

               If histlit is set, the first and second forms print and save the
               literal (unexpanded) form of the history list.

               The last form clears the history list.

       hup [command] (+)
               With command, runs command such that it will exit on a hangup
               signal and arranges for the shell to send it a hangup signal when
               the shell exits.  Note that commands may set their own response
               to hangups, overriding hup.  Without an argument, causes the non-
               interactive shell only to exit on a hangup for the remainder of
               the script.  See also Signal handling and the nohup builtin

       if (expr) command
               If expr (an expression, as described under Expressions) evaluates
               true, then command is executed.  Variable substitution on command
               happens early, at the same time it does for the rest of the if
               command.  command must be a simple command, not an alias, a
               pipeline, a command list or a parenthesized command list, but it
               may have arguments.  Input/output redirection occurs even if expr
               is false and command is thus not executed; this is a bug.

       if (expr) then
       else if (expr2) then
       endif   If the specified expr is true then the commands to the first else
               are executed; otherwise if expr2 is true then the commands to the
               second else are executed, etc.  Any number of else-if pairs are
               possible; only one endif is needed.  The else part is likewise
               optional.  (The words else and endif must appear at the beginning
               of input lines; the if must appear alone on its input line or
               after an else.)

       inlib shared-library ... (+)
               Adds each shared-library to the current environment.  There is no
               way to remove a shared library.  (Domain/OS only)

       jobs [-l]
               Lists the active jobs.  With -l, lists process IDs in addition to
               the normal information.  On TCF systems, prints the site on which
               each job is executing.

       kill [-s signal] %job|pid ...
       kill -l The first and second forms sends the specified signal (or, if
               none is given, the TERM (terminate) signal) to the specified jobs
               or processes.  job may be a number, a string, `', `%', `+' or `-'
               as described under Jobs.  Signals are either given by number or
               by name (as given in /usr/include/signal.h, stripped of the
               prefix `SIG').  There is no default job; saying just `kill' does
               not send a signal to the current job.  If the signal being sent
               is TERM (terminate) or HUP (hangup), then the job or process is
               sent a CONT (continue) signal as well.  The third form lists the
               signal names.

       limit [-h] [resource [maximum-use]]
               Limits the consumption by the current process and each process it
               creates to not individually exceed maximum-use on the specified
               resource.  If no maximum-use is given, then the current limit is
               printed; if no resource is given, then all limitations are given.
               If the -h flag is given, the hard limits are used instead of the
               current limits.  The hard limits impose a ceiling on the values
               of the current limits.  Only the super-user may raise the hard
               limits, but a user may lower or raise the current limits within
               the legal range.

               Controllable resources currently include (if supported by the

                      the maximum number of cpu-seconds to be used by each

                      the largest single file which can be created

                      the maximum growth of the data+stack region via sbrk(2)
                      beyond the end of the program text

                      the maximum size of the automatically-extended stack

                      the size of the largest core dump that will be created

                      the maximum amount of physical memory a process may have
                      allocated to it at a given time

                      the maximum amount of virtual memory a process may have
                      allocated to it at a given time (address space)

                      the maximum amount of virtual memory a process may have
                      allocated to it at a given time

                      the maximum amount of memory a process may allocate per
                      brk() system call

               descriptors or openfiles
                      the maximum number of open files for this process

                      the maximum number of pseudo-terminals for this user

                      the maximum number of kqueues allocated for this process

                      the maximum number of threads for this process

                      the maximum size which a process may lock into memory
                      using mlock(2)

                      the maximum number of simultaneous processes for this user

                      the maximum number of simultaneous threads (lightweight
                      processes) for this user id

                      the maximum number of threads for this process

               sbsize the maximum size of socket buffer usage for this user

                      the maximum amount of swap space reserved or used for this

                      the maximum number of locks for this user

                      the maximum number of POSIX advisory locks for this user

                      the maximum number of pending signals for this user

                      the maximum number of bytes in POSIX mqueues for this user

                      the maximum nice priority the user is allowed to raise
                      mapped from [19...-20] to [0...39] for this user

                      the maximum realtime priority for this user maxrttime the
                      timeout for RT tasks in microseconds for this user.

               maximum-use may be given as a (floating point or integer) number
               followed by a scale factor.  For all limits other than cputime
               the default scale is `k' or `kilobytes' (1024 bytes); a scale
               factor of `m' or `megabytes' or `g' or `gigabytes' may also be
               used.  For cputime the default scaling is `seconds', while `m'
               for minutes or `h' for hours, or a time of the form `mm:ss'
               giving minutes and seconds may be used.

               If maximum-use  is `unlimited', then the limitation on the
               specified resource is removed (this is equivalent to the unlimit
               builtin command).

               For both resource names and scale factors, unambiguous prefixes
               of the names suffice.

       log (+) Prints the watch shell variable and reports on each user
               indicated in watch who is logged in, regardless of when they last
               logged in.  See also watchlog.

       login   Terminates a login shell, replacing it with an instance of
               /bin/login. This is one way to log off, included for
               compatibility with sh(1).

       logout  Terminates a login shell.  Especially useful if ignoreeof is set.

       ls-F [-switch ...] [file ...] (+)
               Lists files like `ls -F', but much faster.  It identifies each
               type of special file in the listing with a special character:

               /   Directory
               *   Executable
               #   Block device
               %   Character device
               |   Named pipe (systems with named pipes only)
               =   Socket (systems with sockets only)
               @   Symbolic link (systems with symbolic links only)
               +   Hidden directory (AIX only) or context dependent (HP/UX only)
               :   Network special (HP/UX only)

               If the listlinks shell variable is set, symbolic links are
               identified in more detail (on only systems that have them, of

               @   Symbolic link to a non-directory
               >   Symbolic link to a directory
               &   Symbolic link to nowhere

               listlinks also slows down ls-F and causes partitions holding
               files pointed to by symbolic links to be mounted.

               If the listflags shell variable is set to `x', `a' or `A', or any
               combination thereof (e.g., `xA'), they are used as flags to ls-F,
               making it act like `ls -xF', `ls -Fa', `ls -FA' or a combination
               (e.g., `ls -FxA').  On machines where `ls -C' is not the default,
               ls-F acts like `ls -CF', unless listflags contains an `x', in
               which case it acts like `ls -xF'.  ls-F passes its arguments to
               ls(1) if it is given any switches, so `alias ls ls-F' generally
               does the right thing.

               The ls-F builtin can list files using different colors depending
               on the filetype or extension.  See the color shell variable and
               the LS_COLORS environment variable.

       migrate [-site] pid|%jobid ... (+)
       migrate -site (+)
               The first form migrates the process or job to the site specified
               or the default site determined by the system path.  The second
               form is equivalent to `migrate -site $$': it migrates the current
               process to the specified site.  Migrating the shell itself can
               cause unexpected behavior, because the shell does not like to
               lose its tty.  (TCF only)

       newgrp [-] [group] (+)
               Equivalent to `exec newgrp'; see newgrp(1).  Available only if
               the shell was so compiled; see the version shell variable.

       nice [+number] [command]
               Sets the scheduling priority for the shell to number, or, without
               number, to 4.  With command, runs command at the appropriate
               priority.  The greater the number, the less cpu the process gets.
               The super-user may specify negative priority by using `nice
               -number ...'.  Command is always executed in a sub-shell, and the
               restrictions placed on commands in simple if statements apply.

       nohup [command]
               With command, runs command such that it will ignore hangup
               signals.  Note that commands may set their own response to
               hangups, overriding nohup.  Without an argument, causes the non-
               interactive shell only to ignore hangups for the remainder of the
               script.  See also Signal handling and the hup builtin command.

       notify [%job ...]
               Causes the shell to notify the user asynchronously when the
               status of any of the specified jobs (or, without %job, the
               current job) changes, instead of waiting until the next prompt as
               is usual.  job may be a number, a string, `', `%', `+' or `-' as
               described under Jobs.  See also the notify shell variable.

       onintr [-|label]
               Controls the action of the shell on interrupts.  Without
               arguments, restores the default action of the shell on
               interrupts, which is to terminate shell scripts or to return to
               the terminal command input level.  With `-', causes all
               interrupts to be ignored.  With label, causes the shell to
               execute a `goto label' when an interrupt is received or a child
               process terminates because it was interrupted.

               onintr is ignored if the shell is running detached and in system
               startup files (see FILES), where interrupts are disabled anyway.

       popd [-p] [-l] [-n|-v] [+n]
               Without arguments, pops the directory stack and returns to the
               new top directory.  With a number `+n', discards the n'th entry
               in the stack.

               Finally, all forms of popd print the final directory stack, just
               like dirs.  The pushdsilent shell variable can be set to prevent
               this and the -p flag can be given to override pushdsilent.  The
               -l, -n and -v flags have the same effect on popd as on dirs.  (+)

       printenv [name] (+)
               Prints the names and values of all environment variables or, with
               name, the value of the environment variable name.

       pushd [-p] [-l] [-n|-v] [name|+n]
               Without arguments, exchanges the top two elements of the
               directory stack.  If pushdtohome is set, pushd without arguments
               does `pushd ~', like cd.  (+) With name, pushes the current
               working directory onto the directory stack and changes to name.
               If name is `-' it is interpreted as the previous working
               directory (see Filename substitution).  (+) If dunique is set,
               pushd removes any instances of name from the stack before pushing
               it onto the stack.  (+) With a number `+n', rotates the nth
               element of the directory stack around to be the top element and
               changes to it.  If dextract is set, however, `pushd +n' extracts
               the nth directory, pushes it onto the top of the stack and
               changes to it.  (+)

               Finally, all forms of pushd print the final directory stack, just
               like dirs.  The pushdsilent shell variable can be set to prevent
               this and the -p flag can be given to override pushdsilent.  The
               -l, -n and -v flags have the same effect on pushd as on dirs.

       rehash  Causes the internal hash table of the contents of the directories
               in the path variable to be recomputed.  This is needed if the
               autorehash shell variable is not set and new commands are added
               to directories in path while you are logged in.  With autorehash,
               a new command will be found automatically, except in the special
               case where another command of the same name which is located in a
               different directory already exists in the hash table.  Also
               flushes the cache of home directories built by tilde expansion.

       repeat count command
               The specified command, which is subject to the same restrictions
               as the command in the one line if statement above, is executed
               count times.  I/O redirections occur exactly once, even if count
               is 0.

       rootnode //nodename (+)
               Changes the rootnode to //nodename, so that `/' will be
               interpreted as `//nodename'.  (Domain/OS only)

       sched (+)
       sched [+]hh:mm command (+)
       sched -n (+)
               The first form prints the scheduled-event list.  The sched shell
               variable may be set to define the format in which the scheduled-
               event list is printed.  The second form adds command to the
               scheduled-event list.  For example,

                   > sched 11:00 echo It\'s eleven o\'clock.

               causes the shell to echo `It's eleven o'clock.' at 11 AM.  The
               time may be in 12-hour AM/PM format

                   > sched 5pm set prompt='[%h] It\'s after 5; go home: >'

               or may be relative to the current time:

                   > sched +2:15 /usr/lib/uucp/uucico -r1 -sother

               A relative time specification may not use AM/PM format.  The
               third form removes item n from the event list:

                   > sched
                        1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother
                        2  Wed Apr  4 17:00  set prompt=[%h] It's after 5; go
                   home: >
                   > sched -2
                   > sched
                        1  Wed Apr  4 15:42  /usr/lib/uucp/uucico -r1 -sother

               A command in the scheduled-event list is executed just before the
               first prompt is printed after the time when the command is
               scheduled.  It is possible to miss the exact time when the
               command is to be run, but an overdue command will execute at the
               next prompt.  A command which comes due while the shell is
               waiting for user input is executed immediately.  However, normal
               operation of an already-running command will not be interrupted
               so that a scheduled-event list element may be run.

               This mechanism is similar to, but not the same as, the at(1)
               command on some Unix systems.  Its major disadvantage is that it
               may not run a command at exactly the specified time.  Its major
               advantage is that because sched runs directly from the shell, it
               has access to shell variables and other structures.  This
               provides a mechanism for changing one's working environment based
               on the time of day.

       set name ...
       set name=word ...
       set [-r] [-f|-l] name=(wordlist) ... (+)
       set name[index]=word ...
       set -r (+)
       set -r name ... (+)
       set -r name=word ... (+)
               The first form of the command prints the value of all shell
               variables.  Variables which contain more than a single word print
               as a parenthesized word list.  The second form sets name to the
               null string.  The third form sets name to the single word.  The
               fourth form sets name to the list of words in wordlist.  In all
               cases the value is command and filename expanded.  If -r is
               specified, the value is set read-only.  If -f or -l are
               specified, set only unique words keeping their order.  -f prefers
               the first occurrence of a word, and -l the last.  The fifth form
               sets the index'th component of name to word; this component must
               already exist.  The sixth form lists only the names of all shell
               variables that are read-only.  The seventh form makes name read-
               only, whether or not it has a value.  The eighth form is the same
               as the third form, but make name read-only at the same time.

               These arguments can be repeated to set and/or make read-only
               multiple variables in a single set command.  Note, however, that
               variable expansion happens for all arguments before any setting
               occurs.  Note also that `=' can be adjacent to both name and word
               or separated from both by whitespace, but cannot be adjacent to
               only one or the other.  See also the unset builtin command.

       setenv [name [value]]
               Without arguments, prints the names and values of all environment
               variables.  Given name, sets the environment variable name to
               value or, without value, to the null string.

       setpath path (+)
               Equivalent to setpath(1).  (Mach only)

       setspath LOCAL|site|cpu ... (+)
               Sets the system execution path.  (TCF only)

       settc cap value (+)
               Tells the shell to believe that the terminal capability cap (as
               defined in termcap(5)) has the value value.  No sanity checking
               is done.  Concept terminal users may have to `settc xn no' to get
               proper wrapping at the rightmost column.

       setty [-d|-q|-x] [-a] [[+|-]mode] (+)
               Controls which tty modes (see Terminal management) the shell does
               not allow to change.  -d, -q or -x tells setty to act on the
               `edit', `quote' or `execute' set of tty modes respectively;
               without -d, -q or -x, `execute' is used.

               Without other arguments, setty lists the modes in the chosen set
               which are fixed on (`+mode') or off (`-mode').  The available
               modes, and thus the display, vary from system to system.  With
               -a, lists all tty modes in the chosen set whether or not they are
               fixed.  With +mode, -mode or mode, fixes mode on or off or
               removes control from mode in the chosen set.  For example, `setty
               +echok echoe' fixes `echok' mode on and allows commands to turn
               `echoe' mode on or off, both when the shell is executing

       setxvers [string] (+)
               Set the experimental version prefix to string, or removes it if
               string is omitted.  (TCF only)

       shift [variable]
               Without arguments, discards argv[1] and shifts the members of
               argv to the left.  It is an error for argv not to be set or to
               have less than one word as value.  With variable, performs the
               same function on variable.

       source [-h] name [args ...]
               The shell reads and executes commands from name.  The commands
               are not placed on the history list.  If any args are given, they
               are placed in argv.  (+) source commands may be nested; if they
               are nested too deeply the shell may run out of file descriptors.
               An error in a source at any level terminates all nested source
               commands.  With -h, commands are placed on the history list
               instead of being executed, much like `history -L'.

       stop %job|pid ...
               Stops the specified jobs or processes which are executing in the
               background.  job may be a number, a string, `', `%', `+' or `-'
               as described under Jobs.  There is no default job; saying just
               `stop' does not stop the current job.

       suspend Causes the shell to stop in its tracks, much as if it had been
               sent a stop signal with ^Z.  This is most often used to stop
               shells started by su(1).

       switch (string)
       case str1:


       endsw   Each case label is successively matched, against the specified
               string which is first command and filename expanded.  The file
               metacharacters `*', `?' and `[...]'  may be used in the case
               labels, which are variable expanded.  If none of the labels match
               before a `default' label is found, then the execution begins
               after the default label.  Each case label and the default label
               must appear at the beginning of a line.  The command breaksw
               causes execution to continue after the endsw.  Otherwise control
               may fall through case labels and default labels as in C.  If no
               label matches and there is no default, execution continues after
               the endsw.

       telltc (+)
               Lists the values of all terminal capabilities (see termcap(5)).

       termname [terminal type] (+)
               Tests if terminal type (or the current value of TERM if no
               terminal type is given) has an entry in the hosts termcap(5) or
               terminfo(5) database. Prints the terminal type to stdout and
               returns 0 if an entry is present otherwise returns 1.

       time [command]
               Executes command (which must be a simple command, not an alias, a
               pipeline, a command list or a parenthesized command list) and
               prints a time summary as described under the time variable.  If
               necessary, an extra shell is created to print the time statistic
               when the command completes.  Without command, prints a time
               summary for the current shell and its children.

       umask [value]
               Sets the file creation mask to value, which is given in octal.
               Common values for the mask are 002, giving all access to the
               group and read and execute access to others, and 022, giving read
               and execute access to the group and others.  Without value,
               prints the current file creation mask.

       unalias pattern
               Removes all aliases whose names match pattern.  `unalias *' thus
               removes all aliases.  It is not an error for nothing to be

       uncomplete pattern (+)
               Removes all completions whose names match pattern.  `uncomplete
               *' thus removes all completions.  It is not an error for nothing
               to be uncompleted.

       unhash  Disables use of the internal hash table to speed location of
               executed programs.

       universe universe (+)
               Sets the universe to universe.  (Masscomp/RTU only)

       unlimit [-hf] [resource]
               Removes the limitation on resource or, if no resource is
               specified, all resource limitations.  With -h, the corresponding
               hard limits are removed.  Only the super-user may do this.  Note
               that unlimit may not exit successful, since most systems do not
               allow descriptors to be unlimited.  With -f errors are ignored.

       unset pattern
               Removes all variables whose names match pattern, unless they are
               read-only.  `unset *' thus removes all variables unless they are
               read-only; this is a bad idea.  It is not an error for nothing to
               be unset.

       unsetenv pattern
               Removes all environment variables whose names match pattern.
               `unsetenv *' thus removes all environment variables; this is a
               bad idea.  It is not an error for nothing to be unsetenved.

       ver [systype [command]] (+)
               Without arguments, prints SYSTYPE.  With systype, sets SYSTYPE to
               systype.  With systype and command, executes command under
               systype.  systype may be `bsd4.3' or `sys5.3'.  (Domain/OS only)

       wait    The shell waits for all background jobs.  If the shell is
               interactive, an interrupt will disrupt the wait and cause the
               shell to print the names and job numbers of all outstanding jobs.

       warp universe (+)
               Sets the universe to universe.  (Convex/OS only)

       watchlog (+)
               An alternate name for the log builtin command (q.v.).  Available
               only if the shell was so compiled; see the version shell

       where command (+)
               Reports all known instances of command, including aliases,
               builtins and executables in path.

       which command (+)
               Displays the command that will be executed by the shell after
               substitutions, path searching, etc.  The builtin command is just
               like which(1), but it correctly reports tcsh aliases and builtins
               and is 10 to 100 times faster.  See also the which-command editor

       while (expr)
       end     Executes the commands between the while and the matching end
               while expr (an expression, as described under Expressions)
               evaluates non-zero.  while and end must appear alone on their
               input lines.  break and continue may be used to terminate or
               continue the loop prematurely.  If the input is a terminal, the
               user is prompted the first time through the loop as with foreach.

   Special aliases (+)
       If set, each of these aliases executes automatically at the indicated
       time.  They are all initially undefined.

       beepcmd Runs when the shell wants to ring the terminal bell.

       cwdcmd  Runs after every change of working directory.  For example, if
               the user is working on an X window system using xterm(1) and a
               re-parenting window manager that supports title bars such as
               twm(1) and does

                   > alias cwdcmd  'echo -n "^[]2;${HOST}:$cwd ^G"'

               then the shell will change the title of the running xterm(1) to
               be the name of the host, a colon, and the full current working
               directory.  A fancier way to do that is

                   > alias cwdcmd 'echo -n "^[]2;${HOST}:$cwd^G^[]1;${HOST}^G"'

               This will put the hostname and working directory on the title bar
               but only the hostname in the icon manager menu.

               Note that putting a cd, pushd or popd in cwdcmd may cause an
               infinite loop.  It is the author's opinion that anyone doing so
               will get what they deserve.

       jobcmd  Runs before each command gets executed, or when the command
               changes state.  This is similar to postcmd, but it does not print

                   > alias jobcmd  'echo -n "^[]2\;\!#:q^G"'

               then executing vi foo.c will put the command string in the xterm
               title bar.

               Invoked by the run-help editor command.  The command name for
               which help is sought is passed as sole argument.  For example, if
               one does

                   > alias helpcommand '\!:1 --help'

               then the help display of the command itself will be invoked,
               using the GNU help calling convention.  Currently there is no
               easy way to account for various calling conventions (e.g., the
               customary Unix `-h'), except by using a table of many commands.

               Runs every tperiod minutes.  This provides a convenient means for
               checking on common but infrequent changes such as new mail.  For
               example, if one does

                   > set tperiod = 30
                   > alias periodic checknews

               then the checknews(1) program runs every 30 minutes.  If periodic
               is set but tperiod is unset or set to 0, periodic behaves like

       precmd  Runs just before each prompt is printed.  For example, if one

                   > alias precmd date

               then date(1) runs just before the shell prompts for each command.
               There are no limits on what precmd can be set to do, but
               discretion should be used.

       postcmd Runs before each command gets executed.

                   > alias postcmd  'echo -n "^[]2\;\!#:q^G"'

               then executing vi foo.c will put the command string in the xterm
               title bar.

       shell   Specifies the interpreter for executable scripts which do not
               themselves specify an interpreter.  The first word should be a
               full path name to the desired interpreter (e.g., `/bin/csh' or

   Special shell variables
       The variables described in this section have special meaning to the

       The shell sets addsuffix, argv, autologout, csubstnonl, command,
       echo_style, edit, gid, group, home, loginsh, oid, path, prompt, prompt2,
       prompt3, shell, shlvl, tcsh, term, tty, uid, user and version at startup;
       they do not change thereafter unless changed by the user.  The shell
       updates cwd, dirstack, owd and status when necessary, and sets logout on

       The shell synchronizes group, home, path, shlvl, term and user with the
       environment variables of the same names: whenever the environment
       variable changes the shell changes the corresponding shell variable to
       match (unless the shell variable is read-only) and vice versa.  Note that
       although cwd and PWD have identical meanings, they are not synchronized
       in this manner, and that the shell automatically converts between the
       different formats of path and PATH.

       addsuffix (+)
               If set, filename completion adds `/' to the end of directories
               and a space to the end of normal files when they are matched
               exactly.  Set by default.

       afsuser (+)
               If set, autologout's autolock feature uses its value instead of
               the local username for kerberos authentication.

       ampm (+)
               If set, all times are shown in 12-hour AM/PM format.

       anyerror (+)
               This variable selects what is propagated to the value of the
               status variable. For more information see the description of the
               status variable below.

       argv    The arguments to the shell.  Positional parameters are taken from
               argv, i.e., `$1' is replaced by `$argv[1]', etc.  Set by default,
               but usually empty in interactive shells.

       autocorrect (+)
               If set, the spell-word editor command is invoked automatically
               before each completion attempt.

       autoexpand (+)
               If set, the expand-history editor command is invoked
               automatically before each completion attempt. If this is set to
               onlyhistory, then only history will be expanded and a second
               completion will expand filenames.

       autolist (+)
               If set, possibilities are listed after an ambiguous completion.
               If set to `ambiguous', possibilities are listed only when no new
               characters are added by completion.

       autologout (+)
               The first word is the number of minutes of inactivity before
               automatic logout.  The optional second word is the number of
               minutes of inactivity before automatic locking.  When the shell
               automatically logs out, it prints `auto-logout', sets the
               variable logout to `automatic' and exits.  When the shell
               automatically locks, the user is required to enter his password
               to continue working.  Five incorrect attempts result in automatic
               logout.  Set to `60' (automatic logout after 60 minutes, and no
               locking) by default in login and superuser shells, but not if the
               shell thinks it is running under a window system (i.e., the
               DISPLAY environment variable is set), the tty is a pseudo-tty
               (pty) or the shell was not so compiled (see the version shell
               variable).  See also the afsuser and logout shell variables.

       autorehash (+)
               If set, the internal hash table of the contents of the
               directories in the path variable will be recomputed if a command
               is not found in the hash table.  In addition, the list of
               available commands will be rebuilt for each command completion or
               spelling correction attempt if set to `complete' or `correct'
               respectively; if set to `always', this will be done for both

       backslash_quote (+)
               If set, backslashes (`\') always quote `\', `'', and `"'.  This
               may make complex quoting tasks easier, but it can cause syntax
               errors in csh(1) scripts.

       catalog The file name of the message catalog.  If set, tcsh use
               `tcsh.${catalog}' as a message catalog instead of default `tcsh'.

       cdpath  A list of directories in which cd should search for
               subdirectories if they aren't found in the current directory.

       cdtohome (+)
               If not set, cd requires a directory name, and will not go to the
               home directory if it's omitted.  This is set by default.

       color   If set, it enables color display for the builtin ls-F and it
               passes --color=auto to ls.  Alternatively, it can be set to only
               ls-F or only ls to enable color to only one command.  Setting it
               to nothing is equivalent to setting it to (ls-F ls).

               If set, it enables color escape sequence for NLS message files.
               And display colorful NLS messages.

       command (+)
               If set, the command which was passed to the shell with the -c
               flag (q.v.).

       compat_expr (+)
               If set, the shell will evaluate expressions right to left, like
               the original csh.

       complete (+)
               If set to `igncase', the completion becomes case insensitive.  If
               set to `enhance', completion ignores case and considers hyphens
               and underscores to be equivalent; it will also treat periods,
               hyphens and underscores (`.', `-' and `_') as word separators.
               If set to `Enhance', completion matches uppercase and underscore
               characters explicitly and matches lowercase and hyphens in a
               case-insensitive manner; it will treat periods, hyphens and
               underscores as word separators.

       continue (+)
               If set to a list of commands, the shell will continue the listed
               commands, instead of starting a new one.

       continue_args (+)
               Same as continue, but the shell will execute:

                   echo `pwd` $argv > ~/.<cmd>_pause; %<cmd>

       correct (+)
               If set to `cmd', commands are automatically spelling-corrected.
               If set to `complete', commands are automatically completed.  If
               set to `all', the entire command line is corrected.

       csubstnonl (+)
               If set, newlines and carriage returns in command substitution are
               replaced by spaces.  Set by default.

       cwd     The full pathname of the current directory.  See also the
               dirstack and owd shell variables.

       dextract (+)
               If set, `pushd +n' extracts the nth directory from the directory
               stack rather than rotating it to the top.

       dirsfile (+)
               The default location in which `dirs -S' and `dirs -L' look for a
               history file.  If unset, ~/.cshdirs is used.  Because only
               ~/.tcshrc is normally sourced before ~/.cshdirs, dirsfile should
               be set in ~/.tcshrc rather than ~/.login.

       dirstack (+)
               An array of all the directories on the directory stack.
               `$dirstack[1]' is the current working directory, `$dirstack[2]'
               the first directory on the stack, etc.  Note that the current
               working directory is `$dirstack[1]' but `=0' in directory stack
               substitutions, etc.  One can change the stack arbitrarily by
               setting dirstack, but the first element (the current working
               directory) is always correct.  See also the cwd and owd shell

       dspmbyte (+)
               Has an effect iff 'dspm' is listed as part of the version shell
               variable.  If set to `euc', it enables display and editing EUC-
               kanji(Japanese) code.  If set to `sjis', it enables display and
               editing Shift-JIS(Japanese) code.  If set to `big5', it enables
               display and editing Big5(Chinese) code.  If set to `utf8', it
               enables display and editing Utf8(Unicode) code.  If set to the
               following format, it enables display and editing of original
               multi-byte code format:

                   > set dspmbyte = 0000....(256 bytes)....0000

               The table requires just 256 bytes.  Each character of 256
               characters corresponds (from left to right) to the ASCII codes
               0x00, 0x01, ... 0xff.  Each character is set to number 0,1,2 and
               3.  Each number has the following meaning:
                 0 ... not used for multi-byte characters.
                 1 ... used for the first byte of a multi-byte character.
                 2 ... used for the second byte of a multi-byte character.
                 3 ... used for both the first byte and second byte of a multi-
               byte character.

               If set to `001322', the first character (means 0x00 of the ASCII
               code) and second character (means 0x01 of ASCII code) are set to
               `0'.  Then, it is not used for multi-byte characters.  The 3rd
               character (0x02) is set to '1', indicating that it is used for
               the first byte of a multi-byte character.  The 4th
               character(0x03) is set '3'.  It is used for both the first byte
               and the second byte of a multi-byte character.  The 5th and 6th
               characters (0x04,0x05) are set to '2', indicating that they are
               used for the second byte of a multi-byte character.

               The GNU fileutils version of ls cannot display multi-byte
               filenames without the -N ( --literal ) option.   If you are using
               this version, set the second word of dspmbyte to "ls".  If not,
               for example, "ls-F -l" cannot display multi-byte filenames.

               This variable can only be used if KANJI and DSPMBYTE has been
               defined at compile time.

       dunique (+)
               If set, pushd removes any instances of name from the stack before
               pushing it onto the stack.

       echo    If set, each command with its arguments is echoed just before it
               is executed.  For non-builtin commands all expansions occur
               before echoing.  Builtin commands are echoed before command and
               filename substitution, because these substitutions are then done
               selectively.  Set by the -x command line option.

       echo_style (+)
               The style of the echo builtin.  May be set to

               bsd     Don't echo a newline if the first argument is `-n'; the
                       default for csh.
               sysv    Recognize backslashed escape sequences in echo strings.
               both    Recognize both the `-n' flag and backslashed escape
                       sequences; the default for tcsh.
               none    Recognize neither.

               Set by default to the local system default.  The BSD and System V
               options are described in the echo(1) man pages on the appropriate

       edit (+)
               If set, the command-line editor is used.  Set by default in
               interactive shells.

       editors (+)
               A list of command names for the run-fg-editor editor command to
               match.  If not set, the EDITOR (`ed' if unset) and VISUAL (`vi'
               if unset) environment variables will be used instead.

       ellipsis (+)
               If set, the `%c'/`%.' and `%C' prompt sequences (see the prompt
               shell variable) indicate skipped directories with an ellipsis
               (`...') instead of `/<skipped>'.

       euid (+)
               The user's effective user ID.

       euser (+)
               The first matching passwd entry name corresponding to the
               effective user ID.

       fignore (+)
               Lists file name suffixes to be ignored by completion.

       filec   In tcsh, completion is always used and this variable is ignored
               by default. If edit is unset, then the traditional csh completion
               is used.  If set in csh, filename completion is used.

       gid (+) The user's real group ID.

       globdot (+)
               If set, wild-card glob patterns will match files and directories
               beginning with `.' except for `.' and `..'

       globstar (+)
               If set, the `**' and `***' file glob patterns will match any
               string of characters including `/' traversing any existing sub-
               directories.  (e.g.  `ls **.c' will list all the .c files in the
               current directory tree).  If used by itself, it will match zero
               or more sub-directories (e.g. `ls /usr/include/**/time.h' will
               list any file named `time.h' in the /usr/include directory tree;
               whereas `ls /usr/include/**time.h' will match any file in the
               /usr/include directory tree ending in `time.h').  To prevent
               problems with recursion, the `**' glob-pattern will not descend
               into a symbolic link containing a directory.  To override this,
               use `***'

       group (+)
               The user's group name.

               If set, the incremental search match (in i-search-back and i-
               search-fwd) and the region between the mark and the cursor are
               highlighted in reverse video.

               Highlighting requires more frequent terminal writes, which
               introduces extra overhead. If you care about terminal
               performance, you may want to leave this unset.

               A string value determining the characters used in History
               substitution (q.v.).  The first character of its value is used as
               the history substitution character, replacing the default
               character `!'.  The second character of its value replaces the
               character `^' in quick substitutions.

       histdup (+)
               Controls handling of duplicate entries in the history list.  If
               set to `all' only unique history events are entered in the
               history list.  If set to `prev' and the last history event is the
               same as the current command, then the current command is not
               entered in the history.  If set to `erase' and the same event is
               found in the history list, that old event gets erased and the
               current one gets inserted.  Note that the `prev' and `all'
               options renumber history events so there are no gaps.

       histfile (+)
               The default location in which `history -S' and `history -L' look
               for a history file.  If unset, ~/.history is used.  histfile is
               useful when sharing the same home directory between different
               machines, or when saving separate histories on different
               terminals.  Because only ~/.tcshrc is normally sourced before
               ~/.history, histfile should be set in ~/.tcshrc rather than

       histlit (+)
               If set, builtin and editor commands and the savehist mechanism
               use the literal (unexpanded) form of lines in the history list.
               See also the toggle-literal-history editor command.

       history The first word indicates the number of history events to save.
               The optional second word (+) indicates the format in which
               history is printed; if not given, `%h\t%T\t%R\n' is used.  The
               format sequences are described below under prompt; note the
               variable meaning of `%R'.  Set to `100' by default.

       home    Initialized to the home directory of the invoker.  The filename
               expansion of `~' refers to this variable.

               If set to the empty string or `0' and the input device is a
               terminal, the end-of-file command (usually generated by the user
               by typing `^D' on an empty line) causes the shell to print `Use
               "exit" to leave tcsh.' instead of exiting.  This prevents the
               shell from accidentally being killed.  Historically this setting
               exited after 26 successive EOF's to avoid infinite loops.  If set
               to a number n, the shell ignores n - 1 consecutive end-of-files
               and exits on the nth.  (+) If unset, `1' is used, i.e., the shell
               exits on a single `^D'.

       implicitcd (+)
               If set, the shell treats a directory name typed as a command as
               though it were a request to change to that directory.  If set to
               verbose, the change of directory is echoed to the standard
               output.  This behavior is inhibited in non-interactive shell
               scripts, or for command strings with more than one word.
               Changing directory takes precedence over executing a like-named
               command, but it is done after alias substitutions.  Tilde and
               variable expansions work as expected.

       inputmode (+)
               If set to `insert' or `overwrite', puts the editor into that
               input mode at the beginning of each line.

       killdup (+)
               Controls handling of duplicate entries in the kill ring.  If set
               to `all' only unique strings are entered in the kill ring.  If
               set to `prev' and the last killed string is the same as the
               current killed string, then the current string is not entered in
               the ring.  If set to `erase' and the same string is found in the
               kill ring, the old string is erased and the current one is

       killring (+)
               Indicates the number of killed strings to keep in memory.  Set to
               `30' by default.  If unset or set to less than `2', the shell
               will only keep the most recently killed string.  Strings are put
               in the killring by the editor commands that delete (kill) strings
               of text, e.g. backward-delete-word, kill-line, etc, as well as
               the copy-region-as-kill command.  The yank editor command will
               yank the most recently killed string into the command-line, while
               yank-pop (see Editor commands) can be used to yank earlier killed

       listflags (+)
               If set to `x', `a' or `A', or any combination thereof (e.g.,
               `xA'), they are used as flags to ls-F, making it act like `ls
               -xF', `ls -Fa', `ls -FA' or a combination (e.g., `ls -FxA'): `a'
               shows all files (even if they start with a `.'), `A' shows all
               files but `.' and `..', and `x' sorts across instead of down.  If
               the second word of listflags is set, it is used as the path to

       listjobs (+)
               If set, all jobs are listed when a job is suspended.  If set to
               `long', the listing is in long format.

       listlinks (+)
               If set, the ls-F builtin command shows the type of file to which
               each symbolic link points.

       listmax (+)
               The maximum number of items which the list-choices editor command
               will list without asking first.

       listmaxrows (+)
               The maximum number of rows of items which the list-choices editor
               command will list without asking first.

       loginsh (+)
               Set by the shell if it is a login shell.  Setting or unsetting it
               within a shell has no effect.  See also shlvl.

       logout (+)
               Set by the shell to `normal' before a normal logout, `automatic'
               before an automatic logout, and `hangup' if the shell was killed
               by a hangup signal (see Signal handling).  See also the
               autologout shell variable.

       mail    A list of files and directories to check for incoming mail,
               optionally preceded by a numeric word.  Before each prompt, if 10
               minutes have passed since the last check, the shell checks each
               file and says `You have new mail.' (or, if mail contains multiple
               files, `You have new mail in name.') if the filesize is greater
               than zero in size and has a modification time greater than its
               access time.

               If you are in a login shell, then no mail file is reported unless
               it has been modified after the time the shell has started up, to
               prevent redundant notifications.  Most login programs will tell
               you whether or not you have mail when you log in.

               If a file specified in mail is a directory, the shell will count
               each file within that directory as a separate message, and will
               report `You have n mails.' or `You have n mails in name.' as
               appropriate.  This functionality is provided primarily for those
               systems which store mail in this manner, such as the Andrew Mail

               If the first word of mail is numeric it is taken as a different
               mail checking interval, in seconds.

               Under very rare circumstances, the shell may report `You have
               mail.' instead of `You have new mail.'

       matchbeep (+)
               If set to `never', completion never beeps.  If set to `nomatch',
               it beeps only when there is no match.  If set to `ambiguous', it
               beeps when there are multiple matches.  If set to `notunique', it
               beeps when there is one exact and other longer matches.  If
               unset, `ambiguous' is used.

       nobeep (+)
               If set, beeping is completely disabled.  See also visiblebell.

               If set, restrictions are placed on output redirection to insure
               that files are not accidentally destroyed and that `>>'
               redirections refer to existing files, as described in the
               Input/output section.

       noding  If set, disable the printing of `DING!' in the prompt time
               specifiers at the change of hour.

       noglob  If set, Filename substitution and Directory stack substitution
               (q.v.) are inhibited.  This is most useful in shell scripts which
               do not deal with filenames, or after a list of filenames has been
               obtained and further expansions are not desirable.

       nokanji (+)
               If set and the shell supports Kanji (see the version shell
               variable), it is disabled so that the meta key can be used.

               If set, a Filename substitution or Directory stack substitution
               (q.v.) which does not match any existing files is left untouched
               rather than causing an error.  It is still an error for the
               substitution to be malformed, e.g., `echo [' still gives an

       nostat (+)
               A list of directories (or glob-patterns which match directories;
               see Filename substitution) that should not be stat(2)ed during a
               completion operation.  This is usually used to exclude
               directories which take too much time to stat(2), for example

       notify  If set, the shell announces job completions asynchronously.  The
               default is to present job completions just before printing a

       oid (+) The user's real organization ID.  (Domain/OS only)

       owd (+) The old working directory, equivalent to the `-' used by cd and
               pushd.  See also the cwd and dirstack shell variables.

       padhour If set, enable the printing of padding '0' for hours, in 24 and
               12 hour formats.  E.G.: 07:45:42 vs. 7:45:42.

               To retain compatibily with older versions numeric variables
               starting with 0 are not interpreted as octal. Setting this
               variable enables proper octal parsing.

       path    A list of directories in which to look for executable commands.
               A null word specifies the current directory.  If there is no path
               variable then only full path names will execute.  path is set by
               the shell at startup from the PATH environment variable or, if
               PATH does not exist, to a system-dependent default something like
               `(/usr/local/bin /usr/bsd /bin /usr/bin .)'.  The shell may put
               `.' first or last in path or omit it entirely depending on how it
               was compiled; see the version shell variable.  A shell which is
               given neither the -c nor the -t option hashes the contents of the
               directories in path after reading ~/.tcshrc and each time path is
               reset.  If one adds a new command to a directory in path while
               the shell is active, one may need to do a rehash for the shell to
               find it.

       printexitvalue (+)
               If set and an interactive program exits with a non-zero status,
               the shell prints `Exit status'.

       prompt  The string which is printed before reading each command from the
               terminal.  prompt may include any of the following formatting
               sequences (+), which are replaced by the given information:

               %/  The current working directory.
               %~  The current working directory, but with one's home directory
                   represented by `~' and other users' home directories
                   represented by `~user' as per Filename substitution.  `~user'
                   substitution happens only if the shell has already used
                   `~user' in a pathname in the current session.
               %c[[0]n], %.[[0]n]
                   The trailing component of the current working directory, or n
                   trailing components if a digit n is given.  If n begins with
                   `0', the number of skipped components precede the trailing
                   component(s) in the format `/<skipped>trailing'.  If the
                   ellipsis shell variable is set, skipped components are
                   represented by an ellipsis so the whole becomes
                   `...trailing'.  `~' substitution is done as in `%~' above,
                   but the `~' component is ignored when counting trailing
               %C  Like %c, but without `~' substitution.
               %h, %!, !
                   The current history event number.
               %M  The full hostname.
               %m  The hostname up to the first `.'.
               %S (%s)
                   Start (stop) standout mode.
               %B (%b)
                   Start (stop) boldfacing mode.
               %U (%u)
                   Start (stop) underline mode.
               %t, %@
                   The time of day in 12-hour AM/PM format.
               %T  Like `%t', but in 24-hour format (but see the ampm shell
               %p  The `precise' time of day in 12-hour AM/PM format, with
               %P  Like `%p', but in 24-hour format (but see the ampm shell
               \c  c is parsed as in bindkey.
               ^c  c is parsed as in bindkey.
               %%  A single `%'.
               %n  The user name.
               %N  The effective user name.
               %j  The number of jobs.
               %d  The weekday in `Day' format.
               %D  The day in `dd' format.
               %w  The month in `Mon' format.
               %W  The month in `mm' format.
               %y  The year in `yy' format.
               %Y  The year in `yyyy' format.
               %l  The shell's tty.
               %L  Clears from the end of the prompt to end of the display or
                   the end of the line.
               %$  Expands the shell or environment variable name immediately
                   after the `$'.
               %#  `>' (or the first character of the promptchars shell
                   variable) for normal users, `#' (or the second character of
                   promptchars) for the superuser.
                   Includes string as a literal escape sequence.  It should be
                   used only to change terminal attributes and should not move
                   the cursor location.  This cannot be the last sequence in
               %?  The return code of the command executed just before the
               %R  In prompt2, the status of the parser.  In prompt3, the
                   corrected string.  In history, the history string.

               `%B', `%S', `%U' and `%{string%}' are available in only eight-
               bit-clean shells; see the version shell variable.

               The bold, standout and underline sequences are often used to
               distinguish a superuser shell.  For example,

                   > set prompt = "%m [%h] %B[%@]%b [%/] you rang? "
                   tut [37] [2:54pm] [/usr/accts/sys] you rang? _

               If `%t', `%@', `%T', `%p', or `%P' is used, and noding is not
               set, then print `DING!' on the change of hour (i.e, `:00'
               minutes) instead of the actual time.

               Set by default to `%# ' in interactive shells.

       prompt2 (+)
               The string with which to prompt in while and foreach loops and
               after lines ending in `\'.  The same format sequences may be used
               as in prompt (q.v.); note the variable meaning of `%R'.  Set by
               default to `%R? ' in interactive shells.

       prompt3 (+)
               The string with which to prompt when confirming automatic
               spelling correction.  The same format sequences may be used as in
               prompt (q.v.); note the variable meaning of `%R'.  Set by default
               to `CORRECT>%R (y|n|e|a)? ' in interactive shells.

       promptchars (+)
               If set (to a two-character string), the `%#' formatting sequence
               in the prompt shell variable is replaced with the first character
               for normal users and the second character for the superuser.

       pushdtohome (+)
               If set, pushd without arguments does `pushd ~', like cd.

       pushdsilent (+)
               If set, pushd and popd do not print the directory stack.

       recexact (+)
               If set, completion completes on an exact match even if a longer
               match is possible.

       recognize_only_executables (+)
               If set, command listing displays only files in the path that are
               executable.  Slow.

       rmstar (+)
               If set, the user is prompted before `rm *' is executed.

       rprompt (+)
               The string to print on the right-hand side of the screen (after
               the command input) when the prompt is being displayed on the
               left.  It recognizes the same formatting characters as prompt.
               It will automatically disappear and reappear as necessary, to
               ensure that command input isn't obscured, and will appear only if
               the prompt, command input, and itself will fit together on the
               first line.  If edit isn't set, then rprompt will be printed
               after the prompt and before the command input.

       savedirs (+)
               If set, the shell does `dirs -S' before exiting.  If the first
               word is set to a number, at most that many directory stack
               entries are saved.

               If set, the shell does `history -S' before exiting.  If the first
               word is set to a number, at most that many lines are saved.  (The
               number should be less than or equal to the number history
               entries; if it is set to greater than the number of history
               settings, only history entries will be saved) If the second word
               is set to `merge', the history list is merged with the existing
               history file instead of replacing it (if there is one) and sorted
               by time stamp and the most recent events are retained.  If the
               second word of savehist is `merge' and the third word is set to
               `lock', the history file update will be serialized with other
               shell sessions that would possibly like to merge history at
               exactly the same time. (+)

       sched (+)
               The format in which the sched builtin command prints scheduled
               events; if not given, `%h\t%T\t%R\n' is used.  The format
               sequences are described above under prompt; note the variable
               meaning of `%R'.

       shell   The file in which the shell resides.  This is used in forking
               shells to interpret files which have execute bits set, but which
               are not executable by the system.  (See the description of
               Builtin and non-builtin command execution.)  Initialized to the
               (system-dependent) home of the shell.

       shlvl (+)
               The number of nested shells.  Reset to 1 in login shells.  See
               also loginsh.

       status  The exit status from the last command or backquote expansion, or
               any command in a pipeline is propagated to status.  (This is also
               the default csh behavior.)  This default does not match what
               POSIX mandates (to return the status of the last command only).
               To match the POSIX behavior, you need to unset anyerror.

               If the anyerror variable is unset, the exit status of a pipeline
               is determined only from the last command in the pipeline, and the
               exit status of a backquote expansion is not propagated to status.

               If a command terminated abnormally, then 0200 is added to the
               status.  Builtin commands which fail return exit status `1', all
               other builtin commands return status `0'.

       symlinks (+)
               Can be set to several different values to control symbolic link
               (`symlink') resolution:

               If set to `chase', whenever the current directory changes to a
               directory containing a symbolic link, it is expanded to the real
               name of the directory to which the link points.  This does not
               work for the user's home directory; this is a bug.

               If set to `ignore', the shell tries to construct a current
               directory relative to the current directory before the link was
               crossed.  This means that cding through a symbolic link and then
               `cd ..'ing returns one to the original directory.  This affects
               only builtin commands and filename completion.

               If set to `expand', the shell tries to fix symbolic links by
               actually expanding arguments which look like path names.  This
               affects any command, not just builtins.  Unfortunately, this does
               not work for hard-to-recognize filenames, such as those embedded
               in command options.  Expansion may be prevented by quoting.
               While this setting is usually the most convenient, it is
               sometimes misleading and sometimes confusing when it fails to
               recognize an argument which should be expanded.  A compromise is
               to use `ignore' and use the editor command normalize-path (bound
               by default to ^X-n) when necessary.

               Some examples are in order.  First, let's set up some play

                   > cd /tmp
                   > mkdir from from/src to
                   > ln -s from/src to/dst

               Here's the behavior with symlinks unset,

                   > cd /tmp/to/dst; echo $cwd
                   > cd ..; echo $cwd

               here's the behavior with symlinks set to `chase',

                   > cd /tmp/to/dst; echo $cwd
                   > cd ..; echo $cwd

               here's the behavior with symlinks set to `ignore',

                   > cd /tmp/to/dst; echo $cwd
                   > cd ..; echo $cwd

               and here's the behavior with symlinks set to `expand'.

                   > cd /tmp/to/dst; echo $cwd
                   > cd ..; echo $cwd
                   > cd /tmp/to/dst; echo $cwd
                   > cd ".."; echo $cwd
                   > /bin/echo ..
                   > /bin/echo ".."

               Note that `expand' expansion 1) works just like `ignore' for
               builtins like cd, 2) is prevented by quoting, and 3) happens
               before filenames are passed to non-builtin commands.

       tcsh (+)
               The version number of the shell in the format `R.VV.PP', where
               `R' is the major release number, `VV' the current version and
               `PP' the patchlevel.

       term    The terminal type.  Usually set in ~/.login as described under
               Startup and shutdown.

       time    If set to a number, then the time builtin (q.v.) executes
               automatically after each command which takes more than that many
               CPU seconds.  If there is a second word, it is used as a format
               string for the output of the time builtin.  (u) The following
               sequences may be used in the format string:

               %U  The time the process spent in user mode in cpu seconds.
               %S  The time the process spent in kernel mode in cpu seconds.
               %E  The elapsed (wall clock) time in seconds.
               %P  The CPU percentage computed as (%U + %S) / %E.
               %W  Number of times the process was swapped.
               %X  The average amount in (shared) text space used in Kbytes.
               %D  The average amount in (unshared) data/stack space used in
               %K  The total space used (%X + %D) in Kbytes.
               %M  The maximum memory the process had in use at any time in
               %F  The number of major page faults (page needed to be brought
                   from disk).
               %R  The number of minor page faults.
               %I  The number of input operations.
               %O  The number of output operations.
               %r  The number of socket messages received.
               %s  The number of socket messages sent.
               %k  The number of signals received.
               %w  The number of voluntary context switches (waits).
               %c  The number of involuntary context switches.

               Only the first four sequences are supported on systems without
               BSD resource limit functions.  The default time format is `%Uu
               %Ss %E %P %X+%Dk %I+%Oio %Fpf+%Ww' for systems that support
               resource usage reporting and `%Uu %Ss %E %P' for systems that do

               Under Sequent's DYNIX/ptx, %X, %D, %K, %r and %s are not
               available, but the following additional sequences are:

               %Y  The number of system calls performed.
               %Z  The number of pages which are zero-filled on demand.
               %i  The number of times a process's resident set size was
                   increased by the kernel.
               %d  The number of times a process's resident set size was
                   decreased by the kernel.
               %l  The number of read system calls performed.
               %m  The number of write system calls performed.
               %p  The number of reads from raw disk devices.
               %q  The number of writes to raw disk devices.

               and the default time format is `%Uu %Ss %E %P %I+%Oio %Fpf+%Ww'.
               Note that the CPU percentage can be higher than 100% on multi-

       tperiod (+)
               The period, in minutes, between executions of the periodic
               special alias.

       tty (+) The name of the tty, or empty if not attached to one.

       uid (+) The user's real user ID.

       user    The user's login name.

       verbose If set, causes the words of each command to be printed, after
               history substitution (if any).  Set by the -v command line

       version (+)
               The version ID stamp.  It contains the shell's version number
               (see tcsh), origin, release date, vendor, operating system and
               machine (see VENDOR, OSTYPE and MACHTYPE) and a comma-separated
               list of options which were set at compile time.  Options which
               are set by default in the distribution are noted.

               8b    The shell is eight bit clean; default
               7b    The shell is not eight bit clean
               wide  The shell is multibyte encoding clean (like UTF-8)
               nls   The system's NLS is used; default for systems with NLS
               lf    Login shells execute /etc/csh.login before instead of after
                     /etc/csh.cshrc and ~/.login before instead of after
                     ~/.tcshrc and ~/.history.
               dl    `.' is put last in path for security; default
               nd    `.' is omitted from path for security
               vi    vi(1)-style editing is the default rather than
               dtr   Login shells drop DTR when exiting
               bye   bye is a synonym for logout and log is an alternate name
                     for watchlog
               al    autologout is enabled; default
               kan   Kanji is used if appropriate according to locale settings,
                     unless the nokanji shell variable is set
               sm    The system's malloc(3) is used
               hb    The `#!<program> <args>' convention is emulated when
                     executing shell scripts
               ng    The newgrp builtin is available
               rh    The shell attempts to set the REMOTEHOST environment
               afs   The shell verifies your password with the kerberos server
                     if local authentication fails.  The afsuser shell variable
                     or the AFSUSER environment variable override your local
                     username if set.

               An administrator may enter additional strings to indicate
               differences in the local version.

       vimode (+)
               If unset, various key bindings change behavior to be more
               emacs(1)-style: word boundaries are determined by wordchars
               versus other characters.

               If set, various key bindings change behavior to be more
               vi(1)-style: word boundaries are determined by wordchars versus
               whitespace versus other characters; cursor behavior depends upon
               current vi mode (command, delete, insert, replace).

               This variable is unset by bindkey -e and set by bindkey -v.
               vimode may be explicitly set or unset by the user after those
               bindkey operations if required.

       visiblebell (+)
               If set, a screen flash is used rather than the audible bell.  See
               also nobeep.

       watch (+)
               A list of user/terminal pairs to watch for logins and logouts.
               If either the user is `any' all terminals are watched for the
               given user and vice versa.  Setting watch to `(any any)' watches
               all users and terminals.  For example,

                   set watch = (george ttyd1 any console $user any)

               reports activity of the user `george' on ttyd1, any user on the
               console, and oneself (or a trespasser) on any terminal.

               Logins and logouts are checked every 10 minutes by default, but
               the first word of watch can be set to a number to check every so
               many minutes.  For example,

                   set watch = (1 any any)

               reports any login/logout once every minute.  For the impatient,
               the log builtin command triggers a watch report at any time.  All
               current logins are reported (as with the log builtin) when watch
               is first set.

               The who shell variable controls the format of watch reports.

       who (+) The format string for watch messages.  The following sequences
               are replaced by the given information:

               %n  The name of the user who logged in/out.
               %a  The observed action, i.e., `logged on', `logged off' or
                   `replaced olduser on'.
               %l  The terminal (tty) on which the user logged in/out.
               %M  The full hostname of the remote host, or `local' if the
                   login/logout was from the local host.
               %m  The hostname of the remote host up to the first `.'.  The
                   full name is printed if it is an IP address or an X Window
                   System display.

               %M and %m are available on only systems that store the remote
               hostname in /etc/utmp.  If unset, `%n has %a %l from %m.' is
               used, or `%n has %a %l.' on systems which don't store the remote

       wordchars (+)
               A list of non-alphanumeric characters to be considered part of a
               word by the forward-word, backward-word etc., editor commands.
               If unset, the default value is determined based on the state of
               vimode: if vimode is unset, `*?_-.[]~=' is used as the default;
               if vimode is set, `_' is used as the default.

       AFSUSER (+)
               Equivalent to the afsuser shell variable.

       COLUMNS The number of columns in the terminal.  See Terminal management.

       DISPLAY Used by X Window System (see X(1)).  If set, the shell does not
               set autologout (q.v.).

       EDITOR  The pathname to a default editor.  Used by the run-fg-editor
               editor command if the the editors shell variable is unset.  See
               also the VISUAL environment variable.

       GROUP (+)
               Equivalent to the group shell variable.

       HOME    Equivalent to the home shell variable.

       HOST (+)
               Initialized to the name of the machine on which the shell is
               running, as determined by the gethostname(2) system call.

       HOSTTYPE (+)
               Initialized to the type of machine on which the shell is running,
               as determined at compile time.  This variable is obsolete and
               will be removed in a future version.

       HPATH (+)
               A colon-separated list of directories in which the run-help
               editor command looks for command documentation.

       LANG    Gives the preferred character environment.  See Native Language
               System support.

               If set, only ctype character handling is changed.  See Native
               Language System support.

       LINES   The number of lines in the terminal.  See Terminal management.

               The format of this variable is reminiscent of the termcap(5) file
               format; a colon-separated list of expressions of the form
               "xx=string", where "xx" is a two-character variable name.  The
               variables with their associated defaults are:

                   no   0      Normal (non-filename) text
                   fi   0      Regular file
                   di   01;34  Directory
                   ln   01;36  Symbolic link
                   pi   33     Named pipe (FIFO)
                   so   01;35  Socket
                   do   01;35  Door
                   bd   01;33  Block device
                   cd   01;32  Character device
                   ex   01;32  Executable file
                   mi   (none) Missing file (defaults to fi)
                   or   (none) Orphaned symbolic link (defaults to ln)
                   lc   ^[[    Left code
                   rc   m      Right code
                   ec   (none) End code (replaces lc+no+rc)

               You need to include only the variables you want to change from
               the default.

               File names can also be colorized based on filename extension.
               This is specified in the LS_COLORS variable using the syntax
               "*ext=string".  For example, using ISO 6429 codes, to color all
               C-language source files blue you would specify "*.c=34".  This
               would color all files ending in .c in blue (34) color.

               Control characters can be written either in C-style-escaped
               notation, or in stty-like ^-notation.  The C-style notation adds
               ^[ for Escape, _ for a normal space character, and ? for Delete.
               In addition, the ^[ escape character can be used to override the
               default interpretation of ^[, ^, : and =.

               Each file will be written as <lc> <color-code> <rc> <filename>
               <ec>.  If the <ec> code is undefined, the sequence <lc> <no> <rc>
               will be used instead.  This is generally more convenient to use,
               but less general.  The left, right and end codes are provided so
               you don't have to type common parts over and over again and to
               support weird terminals; you will generally not need to change
               them at all unless your terminal does not use ISO 6429 color
               sequences but a different system.

               If your terminal does use ISO 6429 color codes, you can compose
               the type codes (i.e., all except the lc, rc, and ec codes) from
               numerical commands separated by semicolons.  The most common
               commands are:

                       0   to restore default color
                       1   for brighter colors
                       4   for underlined text
                       5   for flashing text
                       30  for black foreground
                       31  for red foreground
                       32  for green foreground
                       33  for yellow (or brown) foreground
                       34  for blue foreground
                       35  for purple foreground
                       36  for cyan foreground
                       37  for white (or gray) foreground
                       40  for black background
                       41  for red background
                       42  for green background
                       43  for yellow (or brown) background
                       44  for blue background
                       45  for purple background
                       46  for cyan background
                       47  for white (or gray) background

               Not all commands will work on all systems or display devices.

               A few terminal programs do not recognize the default end code
               properly.  If all text gets colorized after you do a directory
               listing, try changing the no and fi codes from 0 to the numerical
               codes for your standard fore- and background colors.

       MACHTYPE (+)
               The machine type (microprocessor class or machine model), as
               determined at compile time.

       NOREBIND (+)
               If set, printable characters are not rebound to self-insert-
               command.  See Native Language System support.

       OSTYPE (+)
               The operating system, as determined at compile time.

       PATH    A colon-separated list of directories in which to look for
               executables.  Equivalent to the path shell variable, but in a
               different format.

       PWD (+) Equivalent to the cwd shell variable, but not synchronized to it;
               updated only after an actual directory change.

       REMOTEHOST (+)
               The host from which the user has logged in remotely, if this is
               the case and the shell is able to determine it.  Set only if the
               shell was so compiled; see the version shell variable.

       SHLVL (+)
               Equivalent to the shlvl shell variable.

       SYSTYPE (+)
               The current system type.  (Domain/OS only)

       TERM    Equivalent to the term shell variable.

       TERMCAP The terminal capability string.  See Terminal management.

       USER    Equivalent to the user shell variable.

       VENDOR (+)
               The vendor, as determined at compile time.

       VISUAL  The pathname to a default full-screen editor.  Used by the run-
               fg-editor editor command if the the editors shell variable is
               unset.  See also the EDITOR environment variable.

       /etc/csh.cshrc  Read first by every shell.  ConvexOS, Stellix and Intel
                       use /etc/cshrc and NeXTs use /etc/cshrc.std.  A/UX, AMIX,
                       Cray and IRIX have no equivalent in csh(1), but read this
                       file in tcsh anyway.  Solaris 2.x does not have it
                       either, but tcsh reads /etc/.cshrc.  (+)
       /etc/csh.login  Read by login shells after /etc/csh.cshrc.  ConvexOS,
                       Stellix and Intel use /etc/login, NeXTs use
                       /etc/login.std, Solaris 2.x uses /etc/.login and A/UX,
                       AMIX, Cray and IRIX use /etc/cshrc.
       ~/.tcshrc (+)   Read by every shell after /etc/csh.cshrc or its
       ~/.cshrc        Read by every shell, if ~/.tcshrc doesn't exist, after
                       /etc/csh.cshrc or its equivalent.  This manual uses
                       `~/.tcshrc' to mean `~/.tcshrc or, if ~/.tcshrc is not
                       found, ~/.cshrc'.
       ~/.history      Read by login shells after ~/.tcshrc if savehist is set,
                       but see also histfile.
       ~/.login        Read by login shells after ~/.tcshrc or ~/.history.  The
                       shell may be compiled to read ~/.login before instead of
                       after ~/.tcshrc and ~/.history; see the version shell
       ~/.cshdirs (+)  Read by login shells after ~/.login if savedirs is set,
                       but see also dirsfile.
       /etc/csh.logout Read by login shells at logout.  ConvexOS, Stellix and
                       Intel use /etc/logout and NeXTs use /etc/logout.std.
                       A/UX, AMIX, Cray and IRIX have no equivalent in csh(1),
                       but read this file in tcsh anyway.  Solaris 2.x does not
                       have it either, but tcsh reads /etc/.logout.  (+)
       ~/.logout       Read by login shells at logout after /etc/csh.logout or
                       its equivalent.
       /bin/sh         Used to interpret shell scripts not starting with a `#'.
       /tmp/sh*        Temporary file for `<<'.
       /etc/passwd     Source of home directories for `~name' substitutions.

       The order in which startup files are read may differ if the shell was so
       compiled; see Startup and shutdown and the version shell variable.

       This manual describes tcsh as a single entity, but experienced csh(1)
       users will want to pay special attention to tcsh's new features.

       A command-line editor, which supports emacs(1)-style or vi(1)-style key
       bindings.  See The command-line editor and Editor commands.

       Programmable, interactive word completion and listing.  See Completion
       and listing and the complete and uncomplete builtin commands.

       Spelling correction (q.v.) of filenames, commands and variables.

       Editor commands (q.v.) which perform other useful functions in the middle
       of typed commands, including documentation lookup (run-help), quick
       editor restarting (run-fg-editor) and command resolution (which-command).

       An enhanced history mechanism.  Events in the history list are time-
       stamped.  See also the history command and its associated shell
       variables, the previously undocumented `#' event specifier and new
       modifiers under History substitution, the *-history, history-search-*, i-
       search-*, vi-search-* and toggle-literal-history editor commands and the
       histlit shell variable.

       Enhanced directory parsing and directory stack handling.  See the cd,
       pushd, popd and dirs commands and their associated shell variables, the
       description of Directory stack substitution, the dirstack, owd and
       symlinks shell variables and the normalize-command and normalize-path
       editor commands.

       Negation in glob-patterns.  See Filename substitution.

       New File inquiry operators (q.v.) and a filetest builtin which uses them.

       A variety of Automatic, periodic and timed events (q.v.) including
       scheduled events, special aliases, automatic logout and terminal locking,
       command timing and watching for logins and logouts.

       Support for the Native Language System (see Native Language System
       support), OS variant features (see OS variant support and the echo_style
       shell variable) and system-dependent file locations (see FILES).

       Extensive terminal-management capabilities.  See Terminal management.

       New builtin commands including builtins, hup, ls-F, newgrp, printenv,
       which and where (q.v.).

       New variables that make useful information easily available to the shell.
       See the gid, loginsh, oid, shlvl, tcsh, tty, uid and version shell
       variables and the HOST, REMOTEHOST, VENDOR, OSTYPE and MACHTYPE
       environment variables.

       A new syntax for including useful information in the prompt string (see
       prompt), and special prompts for loops and spelling correction (see
       prompt2 and prompt3).

       Read-only variables.  See Variable substitution.

       When a suspended command is restarted, the shell prints the directory it
       started in if this is different from the current directory.  This can be
       misleading (i.e., wrong) as the job may have changed directories

       Shell builtin functions are not stoppable/restartable.  Command sequences
       of the form `a ; b ; c' are also not handled gracefully when stopping is
       attempted.  If you suspend `b', the shell will then immediately execute
       `c'.  This is especially noticeable if this expansion results from an
       alias.  It suffices to place the sequence of commands in ()'s to force it
       to a subshell, i.e., `( a ; b ; c )'.

       Control over tty output after processes are started is primitive; perhaps
       this will inspire someone to work on a good virtual terminal interface.
       In a virtual terminal interface much more interesting things could be
       done with output control.

       Alias substitution is most often used to clumsily simulate shell
       procedures; shell procedures should be provided rather than aliases.

       Control structures should be parsed rather than being recognized as
       built-in commands.  This would allow control commands to be placed
       anywhere, to be combined with `|', and to be used with `&' and `;'

       foreach doesn't ignore here documents when looking for its end.

       It should be possible to use the `:' modifiers on the output of command

       The screen update for lines longer than the screen width is very poor if
       the terminal cannot move the cursor up (i.e., terminal type `dumb').

       HPATH and NOREBIND don't need to be environment variables.

       Glob-patterns which do not use `?', `*' or `[]' or which use `{}' or `~'
       are not negated correctly.

       The single-command form of if does output redirection even if the
       expression is false and the command is not executed.

       ls-F includes file identification characters when sorting filenames and
       does not handle control characters in filenames well.  It cannot be

       Command substitution supports multiple commands and conditions, but not
       cycles or backward gotos.

       Report bugs at https://bugs.astron.com/, preferably with fixes.  If you
       want to help maintain and test tcsh, add yourself to the mailing list in

       In 1964, DEC produced the PDP-6.  The PDP-10 was a later re-
       implementation.  It was re-christened the DECsystem-10 in 1970 or so when
       DEC brought out the second model, the KI10.

       TENEX was created at Bolt, Beranek & Newman (a Cambridge, Massachusetts
       think tank) in 1972 as an experiment in demand-paged virtual memory
       operating systems.  They built a new pager for the DEC PDP-10 and created
       the OS to go with it.  It was extremely successful in academia.

       In 1975, DEC brought out a new model of the PDP-10, the KL10; they
       intended to have only a version of TENEX, which they had licensed from
       BBN, for the new box.  They called their version TOPS-20 (their
       capitalization is trademarked).  A lot of TOPS-10 users (`The OPerating
       System for PDP-10') objected; thus DEC found themselves supporting two
       incompatible systems on the same hardware--but then there were 6 on the

       TENEX, and TOPS-20 to version 3, had command completion via a user-code-
       level subroutine library called ULTCMD.  With version 3, DEC moved all
       that capability and more into the monitor (`kernel' for you Unix types),
       accessed by the COMND% JSYS (`Jump to SYStem' instruction, the supervisor
       call mechanism [are my IBM roots also showing?]).

       The creator of tcsh was impressed by this feature and several others of
       TENEX and TOPS-20, and created a version of csh which mimicked them.

       The system limits argument lists to ARG_MAX characters.

       The number of arguments to a command which involves filename expansion is
       limited to 1/6th the number of characters allowed in an argument list.

       Command substitutions may substitute no more characters than are allowed
       in an argument list.

       To detect looping, the shell restricts the number of alias substitutions
       on a single line to 20.

       csh(1), emacs(1), ls(1), newgrp(1), sh(1), setpath(1), stty(1), su(1),
       tset(1), vi(1), x(1), access(2), execve(2), fork(2), killpg(2), pipe(2),
       setrlimit(2), sigvec(2), stat(2), umask(2), vfork(2), wait(2), malloc(3),
       setlocale(3), tty(4), a.out(5), termcap(5), environ(7), termio(7),
       Introduction to the C Shell

       This manual documents tcsh 6.21.00 (Astron) 2019-05-08.

       William Joy
         Original author of csh(1)
       J.E. Kulp, IIASA, Laxenburg, Austria
         Job control and directory stack features
       Ken Greer, HP Labs, 1981
         File name completion
       Mike Ellis, Fairchild, 1983
         Command name recognition/completion
       Paul Placeway, Ohio State CIS Dept., 1983-1993
         Command line editor, prompt routines, new glob syntax and numerous
         fixes and speedups
       Karl Kleinpaste, CCI 1983-4
         Special aliases, directory stack extraction stuff, login/logout watch,
         scheduled events, and the idea of the new prompt format
       Rayan Zachariassen, University of Toronto, 1984
         ls-F and which builtins and numerous bug fixes, modifications and
       Chris Kingsley, Caltech
         Fast storage allocator routines
       Chris Grevstad, TRW, 1987
         Incorporated 4.3BSD csh into tcsh
       Christos S. Zoulas, Cornell U. EE Dept., 1987-94
         Ports to HPUX, SVR2 and SVR3, a SysV version of getwd.c, SHORT_STRINGS
         support and a new version of sh.glob.c
       James J Dempsey, BBN, and Paul Placeway, OSU, 1988
         A/UX port
       Daniel Long, NNSC, 1988
       Patrick Wolfe, Kuck and Associates, Inc., 1988
         vi mode cleanup
       David C Lawrence, Rensselaer Polytechnic Institute, 1989
         autolist and ambiguous completion listing
       Alec Wolman, DEC, 1989
         Newlines in the prompt
       Matt Landau, BBN, 1989
       Ray Moody, Purdue Physics, 1989
         Magic space bar history expansion
       Mordechai ????, Intel, 1989
         printprompt() fixes and additions
       Kazuhiro Honda, Dept. of Computer Science, Keio University, 1989
         Automatic spelling correction and prompt3
       Per Hedeland, Ellemtel, Sweden, 1990-
         Various bugfixes, improvements and manual updates
       Hans J. Albertsson (Sun Sweden)
         ampm, settc and telltc
       Michael Bloom
         Interrupt handling fixes
       Michael Fine, Digital Equipment Corp
         Extended key support
       Eric Schnoebelen, Convex, 1990
         Convex support, lots of csh bug fixes, save and restore of directory
       Ron Flax, Apple, 1990
         A/UX 2.0 (re)port
       Dan Oscarsson, LTH Sweden, 1990
         NLS support and simulated NLS support for non NLS sites, fixes
       Johan Widen, SICS Sweden, 1990
         shlvl, Mach support, correct-line, 8-bit printing
       Matt Day, Sanyo Icon, 1990
         POSIX termio support, SysV limit fixes
       Jaap Vermeulen, Sequent, 1990-91
         Vi mode fixes, expand-line, window change fixes, Symmetry port
       Martin Boyer, Institut de recherche d'Hydro-Quebec, 1991
         autolist beeping options, modified the history search to search for the
         whole string from the beginning of the line to the cursor.
       Scott Krotz, Motorola, 1991
         Minix port
       David Dawes, Sydney U. Australia, Physics Dept., 1991
         SVR4 job control fixes
       Jose Sousa, Interactive Systems Corp., 1991
         Extended vi fixes and vi delete command
       Marc Horowitz, MIT, 1991
         ANSIfication fixes, new exec hashing code, imake fixes, where
       Bruce Sterling Woodcock, sterling@netcom.com, 1991-1995
         ETA and Pyramid port, Makefile and lint fixes, ignoreeof=n addition,
         and various other portability changes and bug fixes
       Jeff Fink, 1992
         complete-word-fwd and complete-word-back
       Harry C. Pulley, 1992
         Coherent port
       Andy Phillips, Mullard Space Science Lab U.K., 1992
         VMS-POSIX port
       Beto Appleton, IBM Corp., 1992
         Walking process group fixes, csh bug fixes, POSIX file tests, POSIX
       Scott Bolte, Cray Computer Corp., 1992
         CSOS port
       Kaveh R. Ghazi, Rutgers University, 1992
         Tek, m88k, Titan and Masscomp ports and fixes.  Added autoconf support.
       Mark Linderman, Cornell University, 1992
         OS/2 port
       Mika Liljeberg, liljeber@kruuna.Helsinki.FI, 1992
         Linux port
       Tim P. Starrin, NASA Langley Research Center Operations, 1993
         Read-only variables
       Dave Schweisguth, Yale University, 1993-4
         New man page and tcsh.man2html
       Larry Schwimmer, Stanford University, 1993
         AFS and HESIOD patches
       Luke Mewburn, RMIT University, 1994-6
         Enhanced directory printing in prompt, added ellipsis and rprompt.
       Edward Hutchins, Silicon Graphics Inc., 1996
         Added implicit cd.
       Martin Kraemer, 1997
         Ported to Siemens Nixdorf EBCDIC machine
       Amol Deshpande, Microsoft, 1997
         Ported to WIN32 (Windows/95 and Windows/NT); wrote all the missing
         library and message catalog code to interface to Windows.
       Taga Nayuta, 1998
         Color ls additions.

       Bryan Dunlap, Clayton Elwell, Karl Kleinpaste, Bob Manson, Steve Romig,
       Diana Smetters, Bob Sutterfield, Mark Verber, Elizabeth Zwicky and all
       the other people at Ohio State for suggestions and encouragement

       All the people on the net, for putting up with, reporting bugs in, and
       suggesting new additions to each and every version

       Richard M. Alderson III, for writing the `T in tcsh' section

Astron 6.21.00                     8 May 2019                            TCSH(1)