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INDENT(1L) INDENT(1L)
NAME
indent - changes the appearance of a C program by insert-
ing or deleting whitespace.
SYNOPSIS
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]
DESCRIPTION
This man page is based on the Info file indent.info, pro-
duced 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.
COPYING
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.
INTRODUCTION
The `indent' program can be used to make code easier to
read. It can also convert from one style of writing C to
another.
`indent' 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.
INVOKING INDENT
As of version 1.3, the format of the `indent' command is:
indent [OPTIONS] [INPUT-FILES]
indent [OPTIONS] [SINGLE-INPUT-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.
`indent' makes a backup copy of each file, and the origi-
nal file is replaced with its indented version. *Note
Backup files::, for an explanation of how backups are
made.
In the second form, only one input file is specified. In
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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 `+'. `+' 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.
Here is another example:
indent -br test/metabolism.c -l85
This 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'.
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 +line-length185
test/metabolism.c
If you find that you often use `indent' with the same
options, you may put those options into a file called
`.indent.pro'. `indent' will first look for `.indent.pro'
in the current directory and use that if found. Other-
wise, `indent' will search your home directory for
`.indent.pro' and use that file if it is found. This
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behaviour is different from that of other versions of
`indent', which load both files if they both exist.
Command line switches are handled *after* processing
`.indent.pro'. Options specified later override arguments
specified earlier, with one exception: Explicitly speci-
fied options always override background options (*note
Common styles::.). You can prevent `indent' from reading
an `.indent.pro' file by specifying the `-npro' option.
BACKUP FILES
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 suf-
fix 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 `SIM-
PLE_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 par-
ticular 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 back-
ups will be made. If its value is `numbered-existing',
then numbered backups will be made if there *already
exist* numbered backups for the file being indented; oth-
erwise, a simple backup is made. If `VERSION_CONTROL' is
not set, then `indent' assumes the behaviour of `numbered-
existing'.
Other versions of `indent' use the suffix `.BAK' in naming
backup files. This behaviour can be emulated by setting
`SIMPLE_BACKUP_SUFFIX' to `.BAK'.
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
There are several common styles of C code, including the
GNU style, the Kernighan & Ritchie style, and the original
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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 neccessary to spec-
ify 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 that 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 specifyfying
`--original', using 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
BLANK LINES
Various programming styles use blank lines in different
places. `indent' 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
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causes `indent' not to force such blank lines.
The `-bap' option forces a blank line after every proce-
dure 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;
`indent -bad' produces
char *foo;
char *bar;
/* This separates blocks of declarations. */
int baz;
and `indent -nbad' produces
char *foo;
char *bar;
/* This separates blocks of declarations. */
int baz;
The `-bap' option forces a blank line after every proce-
dure body. For example, given the input
int
foo ()
{
puts("Hi");
}
/* The procedure bar is even less interesting. */
char *
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bar ()
{
puts("Hello");
}
`indent -bap' produces
int
foo ()
{
puts ("Hi");
}
/* The procedure bar is even less interesting. */
char *
bar ()
{
puts ("Hello");
}
and `indent -nbap' 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
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
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comments two spaces to the left of 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 */
`-cdb' only affects block comments, not comments to the
right of code. The default is `-ncdb'.
Comments which 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. */
STATEMENTS
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)
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{
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. `-bli0' 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-then-else construct to cuddle up to the immediately
preceding `}'. For example, with `-br -ce' you get the
following:
if (x > 0) {
x--;
} else {
fprintf (stderr, "...something wrong?0);
}
With `-br -nce' that code would appear as
if (x > 0) {
x--;
}
else {
fprintf (stderr, "...something wrong?0);
}
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 semi-
colon, making it clear that the body of the `for' or
`while' statement is an empty statement. `-nss' disables
this feature.
The `-pcs' option causes a space to be placed between the
name of the procedure being called and the `(' (for exam-
ple, `puts ("Hi");'. The `-npcs' option would give
`puts("Hi");').
If the `-cs' option is specified, `indent' puts a space
after a cast operator.
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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.
DECLARATIONS
By default `indent' will line up identifiers, in the col-
umn specified by the `-di' option. For example, `-di16'
makes things look like:
int foo;
char *bar;
Using a small value (such as one or two) for the `-di'
option can be used to cause the indentifiers 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 which 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 this would look like
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' func-
tions 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'.
`-T' can be specified more than once, and all names speci-
fied are used. For example, if your program contains
typedef unsigned long CODE_ADDR;
typedef enum {red, blue, green} COLOR;
you would use the options `-T CODE_ADDR -T COLOR'.
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INDENTATION
One issue in the formatting of code is how far each line
should be indented from the left margin. When the begin-
ning 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
eight character indentation for each level. When a state-
ment is continued from a previous line, it is indented by
a number of additional spaces specified by the `-ci'
option. `-ci' defaults to 0. However, if the `-lp' option
is specified, and a line has a left parenthesis which 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 look like
this with `-nlp -ci3' in effect:
p1 = first_procedure (second_procedure (p2, p3),
third_procedure (p4, p5));
With `-lp' in effect the code looks somewhat clearer:
p1 = first_procedure (second_procedure (p2, p3),
third_procedure (p4, p5));
`indent' assumes that tabs are placed at regular intervals
of both input and output character streams. These inter-
vals 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 to indent
type declarations. 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
To find out what version of `indent' you have, use the
command `indent -version'. This will report the version
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number of `indent', without doing any of the normal pro-
cessing.
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 more lines of output, and gives
some size statistics at completion.
COPYRIGHT
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.
OPTIONS
Here is a list of all the options for `indent', alphabet-
ized by short option. It is followed by a cross key
alphabetized by long option.
`-bad'
`--blank-lines-after-declarations'
Force blank lines after the declarations.
`-bap'
`--blank-lines-after-procedures'
Force blank lines after procedure bodies.
`-bbb'
`--blank-lines-after-block-comments'
Force blank lines after block comments.
`-bc'
`--blank-lines-after-commas'
Force newline after comma in declaration.
`-bl'
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`--braces-after-if-line'
Put braces on line after `if', etc.
`-bliN'
`--brace-indentN'
Indent braces N spaces.
`-br'
`--braces-on-if-line'
Put braces on line with `if', etc.
`-cN'
`--comment-indentationN'
Put comments to the right of code in column N.
`-cdN'
`--declaration-comment-columnN'
Put comments to the right of the declarations in column N.
`-cdb'
`--comment-delimiters-on-blank-lines'
Put comment delimiters on blank lines.
`-ce'
`--cuddle-else'
Cuddle else and preceeding `}'.
`-ciN'
`--continuation-indentationN'
Continuation indent of N spaces.
`-cliN'
`--case-indentationN'
Case label indent of N spaces.
`-cpN'
`--else-endif-columnN'
Put comments to the right of `#else' and `#endif' statements in
column N.
`-cs'
`--space-after-cast'
Put a space after a cast operator.
`-bs'
`--blank-before-sizeof'
Put a space between `sizeof' and its argument.
`-dN'
`--line-comments-indentationN'
Set indentation of comments not to the right of code to N spaces.
`-diN'
`--declaration-indentationN'
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Put variables in column N.
`-fc1'
`--format-first-column-comments'
Format comments in the first column.
`-fca'
`--format-all-comments'
Do not disable all formatting of comments.
`-gnu'
`--gnu-style'
Use GNU coding style. This is the default.
`-iN'
`--indent-levelN'
Set indentation level to N spaces.
`-ipN'
`--parameter-indentationN'
Indent parameter types in old-style function definitions by N
spaces.
`-kr'
`--k-and-r-style'
Use Kernighan & Ritchie coding style.
`-lN'
`--line-lengthN'
Set maximum line length to N.
`-lp'
`--continue-at-parentheses'
Line up continued lines at parentheses.
`-nbad'
`--no-blank-lines-after-declarations'
Do not force blank lines after declarations.
`-nbap'
`--no-blank-lines-after-procedures'
Do not force blank lines after procedure bodies.
`-nbbb'
`--no-blank-lines-after-block-comments'
Do not force blank-lines after block comments.
`-nbc'
`--no-blank-lines-after-commas'
Do not force newlines after commas in declarations.
`-ncdb'
`--no-comment-delimiters-on-blank-lines'
Do not put comment delimiters on blank lines.
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`-nce'
`--dont-cuddle-else'
Do not cuddle `}' and `else'.
`-ncs'
`--no-space-after-casts'
Do not put a space after cast operators.
`-nfc1'
`--dont-format-first-column-comments'
Do not format comments in the first column as normal.
`-nfca'
`--dont-format-comments'
Do not format any comments.
`-nip'
`--no-parameter-indentation'
Zero width indentation for parameters.
`-nlp'
`--dont-line-up-parentheses'
Do not line up parentheses.
`-npcs'
`--no-space-after-function-call-names'
Do not put space after the function in function calls.
`-npsl'
`--dont-break-procedure-type'
Put the type of a procedure on the same line as its name.
`-nsc'
`--dont-star-comments'
Do not put the `*' character at the left of comments.
`-nsob'
`--leave-optional-blank-lines'
Do not swallow optional blank lines.
`-nss'
`--dont-space-special-semicolon'
Do not force a space before the semicolon after certain statements.
Disables `-ss'.
`-nv'
`--no-verbosity'
`-orig'
`--original'
Use the original Berkeley coding style.
`-npro'
`--ignore-profile'
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Do not read `.indent.pro' files.
`-pcs'
`--space-after-procedure-calls'
Insert a space between the name of the procedure being called and
the `('.
`-psl'
`--procnames-start-lines'
Put the type of a procedure on the line before its name.
`-sc'
`--start-left-side-of-comments'
Put the `*' character at the left of comments.
`-sob'
`--swallow-optional-blank-lines'
Swallow optional blank lines.
`-ss'
`--space-special-semicolon'
On one-line `for' and `while' statments, force a blank before the
semicolon.
`-st'
`--standard-output'
Write to standard output.
`-T'
Tell `indent' the name of typenames.
`-tsN'
`--tab-sizeN'
Set tab size to N spaces.
`-v'
`--verbose'
Enable verbose mode.
`-version'
Output the version number of `indent'.
OPTIONS CROSS-REFERENCE
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
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--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
RETURN VALUE
Unknown
FILES
$HOME/.indent.pro holds default options for indent.
16
INDENT(1L) INDENT(1L)
AUTHOR
The Free Software Foundation.
HISTORY
Derived from the UCB program "indent".