indent - changes the appearance of a C program by inserting
or deleting whitespace
indent [-bad] [-bap] [-bbb] [-bc] [-bl] [-bliN] [-br]
[-cN] [-cdN] [-cdb] [-ce] [-ciN] [-cliN] [-cpN] [-cs]
[-bs] [-dN] [-diN] [-fc1] [-fca] [-gnu] [-iN] [-ipN] [-kr]
[-lN] [-lp] [-nbad] [-nbap] [-nbbb] [-nbc] [-ncdb] [-nce]
[-ncs] [-nfc1] [-nfca] [-nip] [-nlp] [-npcs] [-npsl]
[-nsc] [-nsob] [-nss] [-nv] [-orig] [-npro] [-pcs] [-psl]
[-sc] [-sob] [-ss] [-st] [-T] [-tsN] [-v] [-version]
[file]
Here is a list of all the options for indent, alphabetized
by short option. It is followed by a cross key alphabetized
by long option. Force blank lines after the declarations.
Long option: --blank-lines-after-declarations Force
blank lines after procedure bodies.
Long option: --blank-lines-after-procedures Force
blank lines after block comments.
Long option: --blank-lines-after-block-comments
Force newline after comma in declaration.
Long option: --blank-lines-after-commas Put braces
on line after if, etc.
Long option: --braces-after-if-line Indent braces N
spaces.
Long option: --brace-indentN Put braces on line
with if, etc.
Long option:--braces-on-if-line Put comments to the
right of code in column N.
Long option: --comment-indentationN Put comments to
the right of the declarations in column N.
Long option: --declaration-comment-columnN Put comment
delimiters on blank lines.
Long option: --comment-delimiters-on-blank-lines
Cuddle else and preceding }.
Long option: --cuddle-else Continuation indent of N
spaces.
Long option: --continuation-indentationN Case label
indent of N spaces.
Long option: --case-indentationN Put comments to
the right of #else and #endif statements in column
N.
Long option: --else-endif-columnN Put a space after
a cast operator.
Long option: --space-after-cast Put a space between
sizeof and its argument.
Long option: --blank-before-sizeof Set indentation
of comments not to the right of code to N spaces.
Long option: --line-comments-indentationN Put variables
in column N.
Long option: --declaration-indentationN Format comments
in the first column.
Long option: --format-first-column-comments Do not
disable all formatting of comments.
Long option: --format-all-comments Use GNU coding
style. This is the default.
Long option: --gnu-style Set indentation level to N
spaces.
Long option: --indent-levelN Indent parameter types
in old-style function definitions by N spaces.
Long option: --parameter-indentationN Use Kernighan
& Ritchie coding style.
Long option: --k-and-r-style Set maximum line
length to N.
Long option: --line-lengthN Line up continued lines
at parentheses.
Long option: --continue-at-parentheses Do not force
blank lines after declarations.
Long option: --no-blank-lines-after-declarations Do
not force blank lines after procedure bodies.
Long option: --no-blank-lines-after-procedures Do
not force blank-lines after block comments.
Long option: --no-blank-lines-after-block-comments
Do not force newlines after commas in declarations.
Long option: --no-blank-lines-after-commas Do not
put comment delimiters on blank lines.
Long option: --no-comment-delimiters-on-blank-lines
Do not cuddle } and else.
Long option: --dont-cuddle-else Do not put a space
after cast operators.
Long option: --no-space-after-casts Do not format
comments in the first column as normal.
Long option: --dont-format-first-column-comments Do
not format any comments.
Long option: --dont-format-comments Zero width
indentation for parameters.
Long option: --no-parameter-indentation Do not line
up parentheses.
Long option: --dont-line-up-parentheses Do not put
space after the function in function calls.
Long option: --no-space-after-function-call-names
Put the type of a procedure on the same line as its
name.
Long option: --dont-break-procedure-type Do not put
the * character at the left of comments.
Long option: --dont-star-comments Do not swallow
optional blank lines.
Long option: --leave-optional-blank-lines Do not
force a space before the semicolon after certain
statements. Disables -ss.
Long option: --dont-space-special-semicolon Long
option: --no-verbosity Use the original Berkeley
coding style.
Long option: --original Do not read files.
Long option: --ignore-profile Insert a space
between the name of the procedure being called and
the (.
Long option: --space-after-procedure-calls Put the
type of a procedure on the line before its name.
Long option: --procnames-start-lines Put the *
character at the left of comments.
Long option: --start-left-side-of-comments Swallow
optional blank lines.
Long option: --swallow-optional-blank-lines On oneline
for and while statements, force a blank before
the semicolon.
Long option: --space-special-semicolon Write to
standard output.
Long option: --standard-output Tell indent the name
of typenames. Set tab size to N spaces.
Long option: --tab-sizeN Enable verbose mode.
Long option: --verbose Output the version number of
indent.
OPTIONS CROSS-REFERENCE [Toc] [Back] Here is a list of options alphabetized by long option to
help you find the corresponding short option.
--blank-lines-after-block-comments -bbb
--blank-lines-after-commas -bc
--blank-lines-after-declarations -bad
--blank-lines-after-procedures -bap
--braces-after-if-line -bl
--brace-indent -bli
--braces-on-if-line -br
--case-indentation -cliN
--comment-delimiters-on-blank-lines -cdb
--comment-indentation -cN
--continuation-indentation -ciN
--continue-at-parentheses -lp
--cuddle-else -ce
--declaration-comment-column -cdN
--declaration-indentation -diN
--dont-break-procedure-type -npsl
--dont-cuddle-else -nce
--dont-format-comments -nfca
--dont-format-first-column-comments -nfc1
--dont-line-up-parentheses -nlp
--dont-space-special-semicolon -nss
--dont-star-comments -nsc
--else-endif-column -cpN
--format-all-comments -fca
--format-first-column-comments -fc1
--gnu-style -gnu
--ignore-profile -npro
--indent-level -iN
--k-and-r-style -kr
--leave-optional-blank-lines -nsob
--line-comments-indentation -dN
--line-length -lN
--no-blank-lines-after-block-comments -nbbb
--no-blank-lines-after-commas -nbc
--no-blank-lines-after-declarations -nbad
--no-blank-lines-after-procedures -nbap
--no-comment-delimiters-on-blank-lines -ncdb
--no-space-after-casts -ncs
--no-parameter-indentation -nip
--no-space-after-function-call-names -npcs
--no-verbosity -nv
--original -orig
--parameter-indentation -ipN
--procnames-start-lines -psl
--space-after-cast -cs
--space-after-procedure-calls -pcs
--space-special-semicolon -ss
--standard-output -st
--start-left-side-of-comments -sc
--swallow-optional-blank-lines -sob
--tab-size -tsN
--verbose -v
This man page is based on the Info file indent.info, produced
by Makeinfo-1.47 from the input file indent.texinfo.
This is Edition 0.02, 5 May 1992, of The indent Manual
(for indent Version 1.3).
Copyright (C) 1989, 1992 Free Software Foundation, Inc.
Permission is granted to make and distribute verbatim
copies of this manual provided the copyright notice and
this permission notice are preserved on all copies.
The indent program can be used to make code easier to
read. It can also convert from one style of writing C to
another.
The indent program understands a substantial amount about
the syntax of C, but it also attempts to cope with incomplete
and misformed syntax.
In version 1.2 and more recent versions, the GNU style of
indenting is the default.
As of version 1.3, the format of the indent command is:
indent [OPTIONS] [INPUT-FILES] indent [OPTIONS] [SINGLEINPUT-FILE]
[-o OUTPUT-FILE]
This format is different from earlier versions and other
versions of indent.
In the first form, one or more input files are specified.
The indent program makes a backup copy of each file, and
the original file is replaced with its indented version.
For an explanation of how backups are made, see Backup
Files.
In the second form, only one input file is specified. In
this case, or when the standard input is used, you may
specify an output file after the -o option.
To cause indent to write to standard output, use the -st
option. This is only allowed when there is only one input
file, or when the standard input is used.
If no input files are named, the standard input is read
for input. Also, if a filename named - is specified, then
the standard input is read.
As an example, each of the following commands will input
the program slithy_toves.c and write its indented text to
slithy_toves.out:
indent slithy_toves.c -o slithy_toves.out indent -st
slithy_toves.c > slithy_toves.out cat slithy_toves.c |
indent -o slithy_toves.out
Most other options to indent control how programs are formatted.
As of version 1.2, indent also recognizes a long
name for each option name. Long options are prefixed by
either -- or +. The + prefix is being superseded by -- to
maintain consistency with the POSIX standard. In most of
this document, the traditional, short names are used for
the sake of brevity.
As another example, the following command will indent the
program test/metabolism.c using the -br and -l85 options,
write the output back to test/metabolism.c, and write the
original contents of test/metabolism.c to a backup file in
the directory test:
indent -br test/metabolism.c -l85
Equivalent invocations using long option names for this
example would be:
indent --braces-on-if-line --line-length185
test/metabolism.c indent +braces-on-if-line +linelength185
test/metabolism.c
If you find that you often use indent with the same
options, you may put those options into a file named
indent program will first look for in the current directory
and use that file if it is found. Otherwise, indent
will search your home directory for and use that file if
it is found. This behavior is different from that of
other versions of indent, which load both files if they
both exist.
Command line switches are handled *after* processing with
one exception: Explicitly specified options always override
background options (see COMMON STYLES). You can prevent
indent from reading an file by specifying the -npro
option.
As of version 1.3, GNU indent makes GNU-style backup
files, the same way GNU Emacs does. This means that
either "simple" or "numbered" backup filenames may be
made.
Simple backup file names are generated by appending a suffix
to the original file name. The default for the this
suffix is the one-character string ~ (tilde). Thus, the
backup file for python.c would be python.c~.
Instead of the default, you may specify any string as a
suffix by setting the environment variable SIMPLE_BACKUP_SUFFIX
to your preferred suffix.
Numbered backup versions of a file momewraths look like
momewraths.c.~23~, where 23 is the version of this particular
backup. When making a numbered backup of the file
src/momewrath.c, the backup file will be named
src/momewrath.c.~V~, where V is one greater than the highest
version currently existing in the directory src.
The type of backup file made is controlled by the value of
the environment variable VERSION_CONTROL. If it is the
string simple, then only simple backups will be made. If
its value is the string numbered, then numbered backups
will be made. If its value is numbered-existing, then
numbered backups will be made if numbered backups *already
exist* for the file being indented; otherwise, a simple
backup is made. If VERSION_CONTROL is not set, then indent
assumes the behavior of numbered-existing.
Other versions of indent use the suffix in naming backup
files. This behavior can be emulated by setting SIMPLE_BACKUP_SUFFIX
to
Note also that other versions of indent make backups in
the current directory, rather than in the directory of the
source file as GNU indent now does.
Common styles of C code include the GNU style, the
Kernighan & Ritchie style, and the original Berkeley
style. A style may be selected with a single "background"
option, which specifies a set of values for all other
options. However, explicitly specified options always
override options implied by a background option.
As of version 1.2, the default style of GNU indent is the
GNU style. Thus, it is no longer necessary to specify the
option -gnu to obtain this format, although doing so will
not cause an error. Option settings which correspond to
the GNU style are:
-nbad -bap -nbbb -nbc -bl -bli2 -c33 -cd33 -ncdb -nce
-cli0 -cp1 -di0 -nfc1 -nfca -i2 -ip5 -lp -pcs -psl -nsc
-nsob -nss -ts8
The GNU coding style is the style that is preferred by the
GNU project. It is the style that the GNU Emacs C mode
encourages and which is used in the C portions of GNU
Emacs. (People interested in writing programs for Project
GNU should get a copy of The GNU Coding Standards, which
also covers semantic and portability issues such as memory
usage, the size of integers, etc.)
The Kernighan & Ritchie style is used throughout their
well-known book The C Programming Language. It is enabled
with the -kr option. The Kernighan & Ritchie style corresponds
to the following set of options:
-nbad -bap -nbbb -nbc -br -c33 -cd33 -ncdb -ce -ci4 -cli0
-cp33 -d0 -di1 -nfc1 -nfca -i4 -ip0 -l75 -lp -npcs -npsl
-nsc -nsob -nss -ts8
Kernighan & Ritchie style does not put comments to the
right of code in the same column at all times (nor does it
use only one space to the right of the code), so for this
style indent has arbitrarily chosen column 33.
The style of the original Berkeley indent may be obtained
by specifying -orig (or by specifying --original, the long
option name). This style is equivalent to the following
settings: -nbap -nbad -nbbb -bc -br -c33 -cd33 -cdb -ce
-ci4 -cli0 -cp33 -d4 -di16 -fc1 -fca -i4 -ip4 -l75 -lp
-npcs -psl -sc -nsob -nss -ts8
Various programming styles use blank lines in different
places. The indent program has a number of options to
insert or delete blank lines in specific places.
The -bad option causes indent to force a blank line after
every block of declarations. The -nbad option causes
indent not to force such blank lines.
The -bap option forces a blank line after every procedure
body. The -nbap option forces no such blank line.
The -bbb option forces a blank line before every block
comment. A block comment is one which starts in column one
when formatting of such comments is disabled, or one with
- or * immediately following the /*. The -nbbb option does
not force such blank lines.
The -sob option causes indent to swallow optional blank
lines (that is, any optional blank lines present in the
input will be removed from the output). If the -nsob is
specified, any blank lines present in the input file will
be copied to the output file.
The -bad option forces a blank line after every block of
declarations. The -nbad option does not add any such
blank lines.
For example, given the input:
char *foo;
char *bar;
/* This separates blocks of declarations. */
int baz;
The -bad option produces:
char *foo;
char *bar;
/* This separates blocks of declarations. */
int baz;
The -nbad option produces:
char *foo;
char *bar;
/* This separates blocks of declarations. */
int baz;
The -bap option forces a blank line after every procedure
body. For example, given the input:
int
foo ()
{
puts("Hi");
}
/* The procedure bar is even less interesting. */
char *
bar ()
{
puts("Hello");
}
The -bap option produces:
int
foo ()
{
puts ("Hi");
}
/* The procedure bar is even less interesting. */
char *
bar ()
{
puts ("Hello");
}
The -nbap option produces:
int
foo ()
{
puts ("Hi");
}
/* The procedure bar is even less interesting. */
char *
bar ()
{
puts ("Hello");
}
No blank line will be added after the procedure foo.
Comments are no longer formatted by default as of version
1.2. This can be enabled with the -fca option. Doing so
will cause newlines in the comment text to be ignored and
the line will be filled up to the length of a line (which
can be modified with -l). When formatting is enabled,
blank lines indicate paragraph breaks.
The -fc1 option enables the formatting of comments which
begin in the first column. The -nfc1 option disables the
formatting of first column comments. When comment formatting
is disabled, overall comment indentation may still be
adjusted.
The indentation of comments which do not appear to the
right of code is set by the -d option, which specifies the
number of spaces to the left of the surrounding code that
the comment appears. For example, -d2 places comments two
spaces to the left of the code; -d0 lines up comments with
the code. The -cdb option controls whether the /* and */
are placed on blank lines. With -cdb, comments look like
this:
/*
* this is a comment
*/
With -ncdb, comments look like this:
/* this is a comment */
The -cdb option affects only block comments, not comments
to the right of code. The default is -ncdb.
Comments that appear on the same line as code are placed
to the right. The column in which comments on code start
is controlled by the -c option. The column in which comments
to the right of declarations start is controlled by
the -cd option. By default, they start in the same column
as comments to the right of code, which is column 33. The
column number for comments to the right of #else and
#endif statements is controlled by the -cp option. 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.
If the -sc option is specified, * is placed at the left
edge of all comments. For example:
/* This is a comment which extends from one line
* onto the next line, thus causing us to consider
* how it should continue. */
instead of:
/* This is a comment which extends from one line
onto the next line, thus causing us to consider
how it should continue. */
The -br or -bl option specifies how to format braces. The
-br option formats braces like this:
if (x > 0) {
x--;
}
The -bl option formats them like this:
if (x > 0)
{
x--;
}
If you use the -bl option, you may also want to specify
the -bli option. This option specifies the number of
spaces by which braces are indented. -bli2, the default,
gives the result shown above. The -bli0 option results in
the following:
if (x > 0)
{
x--;
}
If you are using the -br option, you probably want to also
use the -ce option. This causes the else in an if-thenelse
construct to cuddle up to the immediately preceding
}. For example, with -br -ce, you get the following:
if (x > 0) {
x--;
} else { <!-- COMMENT follows --> fprintf
(stderr, "...something wrong?\n");
}
With -br -nce, that code would appear as follows:
if (x > 0) {
x--;
}
else { <!-- COMMENT follows --> fprintf
(stderr, "...something wrong?\n");
}
The -cli option specifies the number of spaces that case
labels should be indented to the right of the containing
switch statement.
If a semicolon is on the same line as a for or while
statement, the -ss option will cause a space to be placed
before the semicolon. This emphasizes the semicolon, making
it clear that the body of the for or while statement
is an empty statement. The -nss option disables this feature.
The -pcs option causes a space to be placed between the
name of the procedure being called and the left parenthesis,
for example, puts ("Hi");. The -npcs option would
give puts("Hi");.
If the -cs option is specified, indent puts a space after
a cast operator.
The -bs option ensures that there is a space between the
keyword sizeof and its argument. In some versions, this
is known as the Bill_Shannon option.
By default, indent will line up identifiers in the column
specified by the -di option. For example, -di16 makes
things appear as follows:
int foo;
char *bar;
Using a small value (such as one or two) for the -di
option can be used to cause the identifiers to be placed
in the first available position. For example:
int foo;
char *bar;
The value given to the -di option will still affect variables
that are put on separate lines from their types; for
example, -di2 will lead to:
int
foo;
If the -bc option is specified, a newline is forced after
each comma in a declaration. For example:
int a,
b,
c;
With the -nbc option, the preceding declaration would
appear as follows:
int a, b, c;
The -psl option causes the type of a procedure being
defined to be placed on the line before the name of the
procedure. This style is required for the etags program
to work correctly, as well as some of the c-mode functions
of Emacs.
If you are not using the -di1 option to place variables
being declared immediately after their type, you need to
use the -T option to tell indent the name of all the typenames
in your program that are defined by typedef. The -T
option can be specified more than once, and all names
specified are used. For example, you would use the
options -T CODE_ADDR -T COLOR if your program contains:
typedef unsigned long CODE_ADDR;
typedef enum {red, blue, green} COLOR;
One issue in the formatting of code is how far each line
should be indented from the left margin. When the beginning
of a statement such as if or for is encountered, the
indentation level is increased by the value specified by
the -i option. For example, use -i8 to specify an eightcharacter
indentation for each level. When a statement is
continued from a previous line, it is indented by a number
of additional spaces specified by the -ci option. The -ci
option defaults to 0. However, if the -lp option is specified
and a line has a left parenthesis that is not closed
on that line, then continuation lines will be lined up to
start at the character position just after the left parenthesis.
This processing also applies to [ and applies to
{ when it occurs in initialization lists. For example, a
piece of continued code might appear as follows with -nlp
-ci3 in effect:
p1 = first_procedure (second_procedure (p2, p3),
third_procedure (p4, p5));
With -lp in effect, the code is somewhat clearer:
p1 = first_procedure (second_procedure (p2, p3),
third_procedure (p4, p5));
The indent program assumes that tabs are placed at regular
intervals of both input and output character streams.
These intervals are by default 8 columns wide, but (as of
version 1.2) may be changed by the -ts option. Tabs are
treated as the equivalent number of spaces.
The indentation of type declarations in old-style function
definitions is controlled by the -ip parameter. This is a
numeric parameter specifying how many spaces that type
declarations are to be indented. For example, the default
-ip5 makes definitions look like this:
char *
create_world (x, y, scale)
int x;
int y;
float scale;
{
. . .
}
For compatibility with other versions of indent, the
option -nip is provided, which is equivalent to -ip0.
MISCELLANEOUS OPTIONS [Toc] [Back] To find out what version of indent you have, use the command
indent -version. This will report the version number
of indent, without doing any of the normal processing.
The -v option can be used to turn on verbose mode. When
in verbose mode, indent reports when it splits one line of
input into two more lines of output, and gives some size
statistics at completion.
The following copyright notice applies to the indent program.
The copyright and copying permissions for this manual
appear near the beginning of this document.
Copyright (c) 1989, 1992 Free Software Foundation
Copyright (c) 1985 Sun Microsystems, Inc.
Copyright (c) 1980 The Regents of the University of California.
Copyright (c) 1976 Board of Trustees of the University of
Illinois.
All rights reserved.
Redistribution and use in source and binary forms are permitted
provided that the above copyright notice and this
paragraph are duplicated in all such forms and that any
documentation, advertising materials, and other materials
related to such distribution and use acknowledge that the
software was developed by the University of California,
Berkeley, the University of Illinois, Urbana, and Sun
Microsystems, Inc. The name of either University or Sun
Microsystems may not be used to endorse or promote products
derived from this software without specific prior
written permission. THIS SOFTWARE IS PROVIDED "AS IS" AND
WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTIBILITY
AND FITNESS FOR A PARTICULAR PURPOSE.
Unknown
The Free Software Foundation.
Derived from the UCB program "indent".
Holds default options for the indent program.
indent(1)
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