INDENT(1) General Commands Manual INDENT(1)
NAME
indent – indent and format C program source
SYNOPSIS
indent [input_file [output_file]] [-bacc | -nbacc] [-bad | -nbad]
[-bap | -nbap] [-bbb | -nbbb] [-bc | -nbc] [-bl] [-br] [-cn] [-cdn]
[-cdb | -ncdb] [-ce | -nce] [-cin] [-clin] [-dn] [-din] [-ei | -ei]
[-eei | -eei] [-fbs | -nfbs] [-fc1 | -nfc1] [-fcb | -nfcb] [-in]
[-ip | -nip] [-ln] [-lcn] [-ldin] [-lp | -nlp] [-npro] [-pcs |
-npcs] [-psl | -npsl] [-sc | -nsc] [-sob | -nsob] [-st] [-ta]
[-troff] [-ut | -nut] [-v | -nv]
DESCRIPTION
indent is a C program formatter. It reformats the C program in the
input_file according to the switches. The switches which can be specified
are described below. They may appear before or after the file names.
NOTE: If you only specify an input_file, the formatting is done `in-place',
that is, the formatted file is written back into input_file and a backup
copy of input_file is written in the current directory. If input_file is
named ‘/blah/blah/file’, the backup file is named ‘file.BAK’.
If output_file is specified, indent checks to make sure that it is
different from input_file.
The options listed below control the formatting style imposed by indent.
-bacc, -nbacc If -bacc is specified, a blank line is forced around every
conditional compilation block. For example, in front of
every #ifdef and after every #endif. Other blank lines
surrounding such blocks will be swallowed. The default is
-nbacc.
-bad, -nbad If -bad is specified, a blank line is forced after every
block of declarations. The default is -nbad.
-bap, -nbap If -bap is specified, a blank line is forced after every
procedure body. The default is -nbap.
-bbb, -nbbb If -bbb is specified, a blank line is forced before every
block comment. The default is -nbbb.
-bc, -nbc If -bc is specified, then a newline is forced after each
comma in a declaration. -nbc turns off this option. The
default is -nbc.
-br, -bl Specifying -bl lines-up compound statements like this:
if (...)
{
code
}
Specifying -br (the default) makes them look like this:
if (...) {
code
}
-cn The column in which comments on code start. The default is
33.
-cdn The column in which comments on declarations start. The
default is for these comments to start in the same column
as those on code.
-cdb, -ncdb Enables (disables) the placement of comment delimiters on
blank lines. With this option enabled, comments look like
this:
/*
* this is a comment
*/
Rather than like this:
/* this is a comment */
This only affects block comments, not comments to the right
of code. The default is -cdb.
-ce, -nce Enables (disables) forcing of `else's to cuddle up to the
immediately preceding `}'. The default is -ce.
-cin Sets the continuation indent to be n. Continuation lines
will be indented that far from the beginning of the first
line of the statement. Parenthesized expressions have
extra indentation added to indicate the nesting, unless -lp
is in effect or the continuation indent is exactly half of
the main indent. -ci defaults to the same value as -i.
-clin Causes case labels to be indented n tab stops to the right
of the containing switch statement. -cli0.5 causes case
labels to be indented half a tab stop. The default is
-cli0.
-dn Controls the placement of comments which are not to the
right of code. For example, -d1 means that such comments
are placed one indentation level to the left of code.
Specifying the default -d0 lines-up these comments with the
code. See the section on comment indentation below.
-din Specifies the indentation, in character positions, of
global variable names and all struct/union member names
relative to the beginning of their type declaration. The
default is -di16.
-dj, -ndj -dj left justifies declarations. -ndj indents declarations
the same as code. The default is -ndj.
-ei, -nei Enables (disables) special else-if processing. If it is
enabled, an if following an else will have the same
indentation as the preceding if statement. The default is
-ei.
-eei, -neei Enables (disables) extra indentation on continuation lines
of the expression part of if and while statements. These
continuation lines will be indented one extra level. The
default is -neei.
-fbs, -nfbs Enables (disables) splitting the function declaration and
opening brace across two lines. The default is -fbs.
-fc1, -nfc1 Enables (disables) the formatting of comments that start in
column 1. Often, comments whose leading `/' is in column 1
have been carefully hand formatted by the programmer. In
such cases, -nfc1 should be used. The default is -fc1.
-fcb, -nfcb Enables (disables) the formatting of block comments (ones
that begin with `/*\n'). Often, block comments have been
not so carefully hand formatted by the programmer, but
reformatting that would just change the line breaks is not
wanted. In such cases, -nfcb should be used. Block
comments are then handled like box comments. The default
is -fcb.
-in The number of spaces for one indentation level. The
default is 8.
-ip, -nip Enables (disables) the indentation of parameter
declarations from the left margin. The default is -ip.
-ln Maximum length of an output line. The default is 78.
-ldin Specifies the indentation, in character positions, of local
variable names relative to the beginning of their type
declaration. The default is for local variable names to be
indented by the same amount as global ones.
-lp, -nlp Lines-up code surrounded by parenthesis in continuation
lines. If a line has a left paren which is not closed on
that line, then continuation lines will be lined up to
start at the character position just after the left paren.
For example, here is how a piece of continued code looks
with -nlp in effect:
p1 = first_procedure(second_procedure(p2, p3),
third_procedure(p4, p5));
With -lp in effect (the default) the code looks somewhat
clearer:
p1 = first_procedure(second_procedure(p2, p3),
third_procedure(p4, p5));
Inserting two more newlines we get:
p1 = first_procedure(second_procedure(p2,
p3),
third_procedure(p4,
p5));
-npro Causes the profile files, ‘./.indent.pro’ and
‘~/.indent.pro’, to be ignored.
-pcs, -npcs If true (-pcs) all procedure calls will have a space
inserted between the name and the `('. The default is
-npcs.
-psl, -npsl If true (-psl) the names of procedures being defined are
placed in column 1 - their types, if any, will be left on
the previous lines. The default is -psl.
-sc, -nsc Enables (disables) the placement of asterisks (`*'s) at the
left edge of all comments. The default is -sc.
-sob, -nsob If -sob is specified, indent will swallow optional blank
lines. You can use this to get rid of blank lines after
declarations. The default is -nsob.
-st Causes indent to take its input from stdin and put its
output to stdout.
-ta Automatically add all identifiers ending in "_t" to the
list of type keywords.
-Ttypename Adds typename to the list of type keywords. Names
accumulate: -T can be specified more than once. You need
to specify all the typenames that appear in your program
that are defined by typedef - nothing will be harmed if you
miss a few, but the program will not be formatted as nicely
as it should. This sounds like a painful thing to have to
do, but it is really a symptom of a problem in C: typedef
causes a syntactic change in the language and indent cannot
find all instances of typedef.
-troff Causes indent to format the program for processing by
troff(1). If the output file is not specified, the default
is standard output, rather than formatting in place.
-ut, -nut Enables (disables) the use of tab characters in the output.
Tabs are assumed to be aligned on columns divisible by 8.
The default is -ut.
-v, -nv -v turns on `verbose' mode; -nv turns it off. When in
verbose mode, indent reports when it splits one line of
input into two or more lines of output, and gives some size
statistics at completion. The default is -nv.
You may set up your own `profile' of defaults to indent by creating a file
called .indent.pro in your login directory and/or the current directory and
including whatever switches you like. A `.indent.pro' in the current
directory takes precedence over the one in your login directory. If indent
is run and a profile file exists, then it is read to set up the program's
defaults. Switches on the command line, though, always override profile
switches. The switches should be separated by spaces, tabs or newlines.
Comments
‘Box’ comments. indent assumes that any comment with a dash or star
immediately after the start of comment (that is, `/*-' or `/**') is a
comment surrounded by a box of stars. Each line of such a comment is left
unchanged, except that its indentation may be adjusted to account for the
change in indentation of the first line of the comment.
Straight text. All other comments are treated as straight text. indent
fits as many words (separated by blanks, tabs, or newlines) on a line as
possible. Blank lines break paragraphs.
Comment indentation
If a comment is on a line with code it is started in the `comment column',
which is set by the -cn command line parameter. Otherwise, the comment is
started at n indentation levels less than where code is currently being
placed, where n is specified by the -dn command line parameter. If the
code on a line extends past the comment column, the comment starts further
to the right, and the right margin may be automatically extended in extreme
cases.
Preprocessor lines
In general, indent leaves preprocessor lines alone. The only reformatting
that it will do is to straighten up trailing comments. It leaves embedded
comments alone. Conditional compilation (#ifdef...#endif) is recognized
and indent attempts to correctly compensate for the syntactic peculiarities
introduced.
C syntax
indent understands a substantial amount about the syntax of C, but it has a
`forgiving' parser. It attempts to cope with the usual sorts of incomplete
and misformed syntax. In particular, the use of macros like:
#define forever for(;;)
is handled properly.
ENVIRONMENT
indent uses the HOME environment variable.
FILES
./.indent.pro profile file
~/.indent.pro profile file
HISTORY
The indent command appeared in 4.2BSD.
BUGS
indent has even more switches than ls(1).
A common mistake that often causes grief is typing:
indent *.c
to the shell in an attempt to indent all the C programs in a directory.
This is probably a bug, not a feature.
macOS 12.1 June 29, 2004 macOS 12.1