bzfgrep

GREP(1)                      General Commands Manual                     GREP(1)

NAME
     grep, egrep, fgrep, rgrep, bzgrep, bzegrep, bzfgrep, zgrep, zegrep, zfgrep
     – file pattern searcher

SYNOPSIS
     grep [-abcdDEFGHhIiJLlMmnOopqRSsUVvwXxZz] [-A num] [-B num] [-C[num]]
          [-e pattern] [-f file] [--binary-files=value] [--color[=when]]
          [--colour[=when]] [--context[=num]] [--label] [--line-buffered]
          [--null] [pattern] [file ...]

DESCRIPTION
     The grep utility searches any given input files, selecting lines that match
     one or more patterns.  By default, a pattern matches an input line if the
     regular expression (RE) in the pattern matches the input line without its
     trailing newline.  An empty expression matches every line.  Each input line
     that matches at least one of the patterns is written to the standard
     output.

     grep is used for simple patterns and basic regular expressions (BREs);
     egrep can handle extended regular expressions (EREs).  See re_format(7) for
     more information on regular expressions.  fgrep is quicker than both grep
     and egrep, but can only handle fixed patterns (i.e., it does not interpret
     regular expressions).  Patterns may consist of one or more lines, allowing
     any of the pattern lines to match a portion of the input.

     zgrep, zegrep, and zfgrep act like grep, egrep, and fgrep, respectively,
     but accept input files compressed with the compress(1) or gzip(1)
     compression utilities.  bzgrep, bzegrep, and bzfgrep act like grep, egrep,
     and fgrep, respectively, but accept input files compressed with the
     bzip2(1) compression utility.

     The following options are available:

     -A num, --after-context=num
             Print num lines of trailing context after each match.  See also the
             -B and -C options.

     -a, --text
             Treat all files as ASCII text.  Normally grep will simply print
             “Binary file ... matches” if files contain binary characters.  Use
             of this option forces grep to output lines matching the specified
             pattern.

     -B num, --before-context=num
             Print num lines of leading context before each match.  See also the
             -A and -C options.

     -b, --byte-offset
             The offset in bytes of a matched pattern is displayed in front of
             the respective matched line.

     -C[num], --context[=num]
             Print num lines of leading and trailing context surrounding each
             match.  The default value of num is “2” and is equivalent to “-A 2
             -B 2”.  Note: no whitespace may be given between the option and its
             argument.

     -c, --count
             Only a count of selected lines is written to standard output.

     --colour=[when], --color=[when]
             Mark up the matching text with the expression stored in the
             GREP_COLOR environment variable.  The possible values of when are
             “never”, “always” and “auto”.

     -D action, --devices=action
             Specify the demanded action for devices, FIFOs and sockets.  The
             default action is “read”, which means, that they are read as if
             they were normal files.  If the action is set to “skip”, devices
             are silently skipped.

     -d action, --directories=action
             Specify the demanded action for directories.  It is “read” by
             default, which means that the directories are read in the same
             manner as normal files.  Other possible values are “skip” to
             silently ignore the directories, and “recurse” to read them
             recursively, which has the same effect as the -R and -r option.

     -E, --extended-regexp
             Interpret pattern as an extended regular expression (i.e., force
             grep to behave as egrep).

     -e pattern, --regexp=pattern
             Specify a pattern used during the search of the input: an input
             line is selected if it matches any of the specified patterns.  This
             option is most useful when multiple -e options are used to specify
             multiple patterns, or when a pattern begins with a dash (‘-’).

     --exclude pattern
             If specified, it excludes files matching the given filename pattern
             from the search.  Note that --exclude and --include patterns are
             processed in the order given.  If a name matches multiple patterns,
             the latest matching rule wins.  If no --include pattern is
             specified, all files are searched that are not excluded.  Patterns
             are matched to the full path specified, not only to the filename
             component.

     --exclude-dir pattern
             If -R is specified, it excludes directories matching the given
             filename pattern from the search.  Note that --exclude-dir and
             --include-dir patterns are processed in the order given.  If a name
             matches multiple patterns, the latest matching rule wins.  If no
             --include-dir pattern is specified, all directories are searched
             that are not excluded.

     -F, --fixed-strings
             Interpret pattern as a set of fixed strings (i.e., force grep to
             behave as fgrep).

     -f file, --file=file
             Read one or more newline separated patterns from file.  Empty
             pattern lines match every input line.  Newlines are not considered
             part of a pattern.  If file is empty, nothing is matched.

     -G, --basic-regexp
             Interpret pattern as a basic regular expression (i.e., force grep
             to behave as traditional grep).

     -H      Always print filename headers with output lines.

     -h, --no-filename
             Never print filename headers (i.e., filenames) with output lines.

     --help  Print a brief help message.

     -I      Ignore binary files.  This option is equivalent to the
             “--binary-file=without-match” option.

     -i, --ignore-case
             Perform case insensitive matching.  By default, grep is case
             sensitive.

     --include pattern
             If specified, only files matching the given filename pattern are
             searched.  Note that --include and --exclude patterns are processed
             in the order given.  If a name matches multiple patterns, the
             latest matching rule wins.  Patterns are matched to the full path
             specified, not only to the filename component.

     --include-dir pattern
             If -R is specified, only directories matching the given filename
             pattern are searched.  Note that --include-dir and --exclude-dir
             patterns are processed in the order given.  If a name matches
             multiple patterns, the latest matching rule wins.

     -J, --bz2decompress
             Decompress the bzip2(1) compressed file before looking for the
             text.

     -L, --files-without-match
             Only the names of files not containing selected lines are written
             to standard output.  Pathnames are listed once per file searched.
             If the standard input is searched, the string “(standard input)” is
             written unless a --label is specified.

     -l, --files-with-matches
             Only the names of files containing selected lines are written to
             standard output.  grep will only search a file until a match has
             been found, making searches potentially less expensive.  Pathnames
             are listed once per file searched.  If the standard input is
             searched, the string “(standard input)” is written unless a --label
             is specified.

     --label
             Label to use in place of “(standard input)” for a file name where a
             file name would normally be printed.  This option applies to -H,
             -L, and -l.

     --mmap  Use mmap(2) instead of read(2) to read input, which can result in
             better performance under some circumstances but can cause undefined
             behaviour.

     -M, --lzma
             Decompress the LZMA compressed file before looking for the text.

     -m num, --max-count=num
             Stop reading the file after num matches.

     -n, --line-number
             Each output line is preceded by its relative line number in the
             file, starting at line 1.  The line number counter is reset for
             each file processed.  This option is ignored if -c, -L, -l, or -q
             is specified.

     --null  Prints a zero-byte after the file name.

     -O      If -R is specified, follow symbolic links only if they were
             explicitly listed on the command line.  The default is not to
             follow symbolic links.

     -o, --only-matching
             Prints only the matching part of the lines.

     -p      If -R is specified, no symbolic links are followed.  This is the
             default.

     -q, --quiet, --silent
             Quiet mode: suppress normal output.  grep will only search a file
             until a match has been found, making searches potentially less
             expensive.

     -R, -r, --recursive
             Recursively search subdirectories listed.  (i.e., force grep to
             behave as rgrep).

     -S      If -R is specified, all symbolic links are followed.  The default
             is not to follow symbolic links.

     -s, --no-messages
             Silent mode.  Nonexistent and unreadable files are ignored (i.e.,
             their error messages are suppressed).

     -U, --binary
             Search binary files, but do not attempt to print them.

     -u      This option has no effect and is provided only for compatibility
             with GNU grep.

     -V, --version
             Display version information and exit.

     -v, --invert-match
             Selected lines are those not matching any of the specified
             patterns.

     -w, --word-regexp
             The expression is searched for as a word (as if surrounded by
             ‘[[:<:]]’ and ‘[[:>:]]’; see re_format(7)).  This option has no
             effect if -x is also specified.

     -x, --line-regexp
             Only input lines selected against an entire fixed string or regular
             expression are considered to be matching lines.

     -y      Equivalent to -i.  Obsoleted.

     -z, --null-data
             Treat input and output data as sequences of lines terminated by a
             zero-byte instead of a newline.

     -X, --xz
             Decompress the xz(1) compressed file before looking for the text.

     -Z, --decompress
             Force grep to behave as zgrep.

     --binary-files=value
             Controls searching and printing of binary files.  Options are:
             binary (default)  Search binary files but do not print them.
             without-match     Do not search binary files.
             text              Treat all files as text.

     --line-buffered
             Force output to be line buffered.  By default, output is line
             buffered when standard output is a terminal and block buffered
             otherwise.

     If no file arguments are specified, the standard input is used.
     Additionally, “-” may be used in place of a file name, anywhere that a file
     name is accepted, to read from standard input.  This includes both -f and
     file arguments.

ENVIRONMENT
     GREP_OPTIONS  May be used to specify default options that will be placed at
                   the beginning of the argument list.  Backslash-escaping is
                   not supported, unlike the behavior in GNU grep.

EXIT STATUS
     The grep utility exits with one of the following values:

     0     One or more lines were selected.
     1     No lines were selected.
     >1    An error occurred.

EXAMPLES
     -   Find all occurrences of the pattern ‘patricia’ in a file:

               $ grep 'patricia' myfile

     -   Same as above but looking only for complete words:

               $ grep -w 'patricia' myfile

     -   Count occurrences of the exact pattern ‘FOO’ :

               $ grep -c FOO myfile

     -   Same as above but ignoring case:

               $ grep -c -i FOO myfile

     -   Find all occurrences of the pattern ‘.Pp’ at the beginning of a line:

               $ grep '^\.Pp' myfile

         The apostrophes ensure the entire expression is evaluated by grep
         instead of by the user's shell.  The caret ‘^’ matches the null string
         at the beginning of a line, and the ‘\’ escapes the ‘.’, which would
         otherwise match any character.

     -   Find all lines in a file which do not contain the words ‘foo’ or ‘bar’:

               $ grep -v -e 'foo' -e 'bar' myfile

     -   Peruse the file ‘calendar’ looking for either 19, 20, or 25 using
         extended regular expressions:

               $ egrep '19|20|25' calendar

     -   Show matching lines and the name of the ‘*.h’ files which contain the
         pattern ‘FIXME’.  Do the search recursively from the /usr/src/sys/arm
         directory

               $ grep -H -R FIXME --include=*.h /usr/src/sys/arm/

     -   Same as above but show only the name of the matching file:

               $ grep -l -R FIXME --include=*.h /usr/src/sys/arm/

     -   Show lines containing the text ‘foo’.  The matching part of the output
         is colored and every line is prefixed with the line number and the
         offset in the file for those lines that matched.

               $ grep -b --colour -n foo myfile

     -   Show lines that match the extended regular expression patterns read
         from the standard input:

               $ echo -e 'Free\nBSD\nAll.*reserved' | grep -E -f - myfile

     -   Show lines from the output of the pciconf(8) command matching the
         specified extended regular expression along with three lines of leading
         context and one line of trailing context:

               $ pciconf -lv | grep -B3 -A1 -E 'class.*=.*storage'

     -   Suppress any output and use the exit status to show an appropriate
         message:

               $ grep -q foo myfile && echo File matches

SEE ALSO
     bzip2(1), compress(1), ed(1), ex(1), gzip(1), sed(1), xz(1), zgrep(1),
     re_format(7)

STANDARDS
     The grep utility is compliant with the IEEE Std 1003.1-2008 (“POSIX.1”)
     specification.

     The flags [-AaBbCDdGHhILmoPRSUVw] are extensions to that specification, and
     the behaviour of the -f flag when used with an empty pattern file is left
     undefined.

     All long options are provided for compatibility with GNU versions of this
     utility.

     Historic versions of the grep utility also supported the flags [-ruy].
     This implementation supports those options; however, their use is strongly
     discouraged.

HISTORY
     The grep command first appeared in Version 6 AT&T UNIX.

BUGS
     The grep utility does not normalize Unicode input, so a pattern containing
     composed characters will not match decomposed input, and vice versa.

macOS 12.1                       March 22, 2021                       macOS 12.1