indent.1

indent为linux下代码自动格式化工具

.SH "INVOKING INDENT"

As of version 1.3, the format of the \fBindent\fR command is:

.in +5
.nf
.na

indent [\fIoptions\fR] [\fIinput-files\fR]

indent [\fIoptions\fR] [\fIsingle-input-file\fR] [-o \fIoutput-file\fR]

.in -5
.ad
.fi

This format is different from earlier versions and other versions of
.B indent\fR.

In the first form, one or more input files are specified.  \fBindent\fR
makes a backup copy of each file, and the original file is replaced with
its indented version.  See \fBBACKUP\ FILES\fR, for an explanation of how
backups are made.

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 \fBindent\fR 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\':

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.nf
.na

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

.in -5
.ad
.fi

Most other options to \fBindent\fR control how programs are formatted.
As of version 1.2, \fBindent\fR 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[ \`+\' is being superseded by \`--\' to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.
See \fBOPTION\ SUMMARY\fR, for a list of options, including both long and
short names.

Here is another example:

.in +5
.nf
.na
indent -br test/metabolism.c -l85
.in -5
.ad
.fi

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:

.in +5
.nf
.na

indent --braces-on-if-line --line-length185 test/metabolism.c

indent +braces-on-if-line +line-length185 test/metabolism.c

.in -5
.ad
.fi

If you find that you often use \fBindent\fR with the same options, you
may put those options into a file named \`.indent.pro\'.
.B indent\fR will look for a profile file in three places. First it will check
the environment variable \fBINDENT_PROFILE\fR. If that exists its value 
is expected to name the file that is to be used. If the environment variable does 
not exist, indent looks for \`.indent.pro\' in the current directory
 and use that if found.  Finally \fBindent\fR will search
your home directory for \`.indent.pro\' and use that file if it is
found.  This behaviour is different from that of other versions of
.B indent\fR, which load both files if they both exist.

The format of \`.indent.pro\' is simply a list of options, just as
they would appear on the command line, separated by white space (tabs,
spaces, and newlines).  Options in \`.indent.pro\' may be surrounded by C
or C++ comments, in which case they are ignored.

Command line switches are handled \fIafter\fR processing
\`.indent.pro\'.  Options specified later override arguments
specified earlier, with one exception: Explicitly specified options
always override background options (See \fBCOMMON\ STYLES\fR).  You can
prevent \fBindent\fR from reading an \`.indent.pro\' file by
specifying the \`-npro\' option.

.SH "BACKUP FILES"

As of version 1.3, GNU \fBindent\fR makes GNU-style backup files, the
same way GNU Emacs does.  This means that either \fIsimple\fR or
.I numbered\fR backup filenames may be made.

Simple backup file names are generated by appending a suffix to the
original file name.  The default for 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 \fBSIMPLE_BACKUP_SUFFIX\fR to
your preferred suffix.

Numbered backup versions of a file \`momeraths.c\' look like
\`momeraths.c.~23~\', where 23 is the version of this particular
backup.  When making a numbered backup of the file \`src/momeraths.c\',
the backup file will be named \`src/momeraths.c.~\fIV\fR~\', where
.I V\fR is one greater than the highest version currently existing in
the directory \`src\'.  The environment variable \fBVERSION_WIDTH\fR
controls the number of digits, using left zero padding when necessary.
For instance, setting this variable to "2" will lead to the backup
file being named \`momeraths.c.~04~\'.

The type of backup file made is controlled by the value of the
environment variable \fBVERSION_CONTROL\fR.  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
there \fIalready exist\fR numbered backups for the file being indented;
otherwise, a simple backup is made.  If \fBVERSION_CONTROL\fR is not
set, then \fBindent\fR assumes the behaviour of
\`numbered-existing\'.

Other versions of \fBindent\fR use the suffix \`.BAK\' in naming
backup files.  This behaviour can be emulated by setting
.B SIMPLE_BACKUP_SUFFIX\fR to \`.BAK\'.

Note also that other versions of \fBindent\fR make backups in the
current directory, rather than in the directory of the source file as
GNU \fBindent\fR now does.

.SH "COMMON STYLES"

There are several common styles of C code, including the GNU style, the
Kernighan & Ritchie style, and the original Berkeley style.  A style may
be selected with a single \fIbackground\fR 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 \fBindent\fR 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:

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.nf
.na
-nbad -bap -nbc -bbo -bl -bli2 -bls -ncdb -nce -cp1 -cs -di2
-ndj -nfc1 -nfca -hnl -i2 -ip5 -lp -pcs -nprs -psl -saf -sai
-saw -nsc -nsob
.in -5
.ad
.fi

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:

.in +5
.nf
.na
-nbad -bap -bbo -nbc -br -brs -c33 -cd33 -ncdb -ce -ci4 -cli0
-cp33 -cs -d0 -di1 -nfc1 -nfca -hnl -i4 -ip0 -l75 -lp -npcs
-nprs -npsl -saf -sai -saw -nsc -nsob -nss
.in -5
.ad
.fi

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 \fBindent\fR has arbitrarily
chosen column 33.

The style of the original Berkeley \fBindent\fR may be obtained by
specifying \`-orig\' (or by specifying \`--original\', using the
long option name).  This style is equivalent to the following settings:

.in +5
.nf
.na
-nbad -nbap -bbo -bc -br -brs -c33 -cd33 -cdb -ce -ci4 -cli0
-cp33 -di16 -fc1 -fca -hnl -i4 -ip4 -l75 -lp -npcs -nprs -psl
-saf -sai -saw -sc -nsob -nss -ts8
.in -5
.ad
.fi

.SH "BLANK LINES"

Various programming styles use blank lines in different places.
.B indent\fR has a number of options to insert or delete blank lines in
specific places.

The \`-bad\' option causes \fBindent\fR to force a blank line after
every block of declarations.  The \`-nbad\' option causes
.B indent\fR 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 boxed comment
(See \fBCOMMENTS\fR.)
The \`-nbbb\' option does not force such blank lines.

The \`-sob\' option causes \fBindent\fR 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.


.SH "--blank-lines-after-declarations"

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
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.nf
.na
char *foo;
char *bar;
/* This separates blocks of declarations.  */
int baz;
.in -5
.ad
.fi

.B indent -bad\fR produces

.in +5
.nf
.na
char *foo;
char *bar;

/* This separates blocks of declarations.  */
int baz;
.in -5
.ad
.fi

and \fBindent -nbad\fR produces

.in +5
.nf
.na
char *foo;
char *bar;
/* This separates blocks of declarations.  */
int baz;
.in -5
.ad
.fi

.SH "--blank-lines-after-procedures"

The \`-bap\' option forces a blank line after every procedure body.

For example, given the input

.in +5
.nf
.na
int
foo ()
{
  puts("Hi");
}
/* The procedure bar is even less interesting.  */
char *
bar ()
{
  puts("Hello");
}
.in -5
.ad
.fi

.B indent -bap\fR produces

.in +5
.nf
.na
int
foo ()
{
  puts ("Hi");
}

/* The procedure bar is even less interesting.  */
char *
bar ()
{
  puts ("Hello");
}
.in -5
.ad
.fi

and \fBindent -nbap\fR produces

.in +5
.nf
.na
int
foo ()
{
  puts ("Hi");
}
/* The procedure bar is even less interesting.  */
char *
bar ()
{
  puts ("Hello");
}
.in -5
.ad
.fi

No blank line will be added after the procedure \fBfoo\fR.

.SH "COMMENTS"

.B indent\fR formats both C and C++ comments. C comments are begun with
\`/*\', terminated with \`*/\' and may contain newline characters.
C++ comments begin with the delimiter \`//\' and end at the newline.

.B indent\fR handles comments differently depending upon their context.
.B indent\fR attempts to distinguish between comments which follow
statements, comments which follow declarations, comments following
preprocessor directives, and comments which are not preceded by code of
any sort, i.e., they begin the text of the line (although not
neccessarily in column 1).

.B indent\fR further distinguishes between comments found outside of
procedures and aggregates, and those found within them.  In particular,
comments beginning a line found within a procedure will be indented to
the column at which code is currently indented.  The exception to this a
comment beginning in the leftmost column;  such a comment is output
at that column.

.B indent\fR attempts to leave \fIboxed comments\fR unmodified.  The
general idea of such a comment is that it is enclosed in a rectangle or
\`\`box\'\' of stars or dashes to visually set it apart.  More precisely,
boxed comments are defined as those in which the initial \`/*\' is
followed immediately by the character \`*\', \`=\', \`_\', or
\`-\', or those in which the beginning comment delimiter (\`/*\')
is on a line by itself, and the following line begins with a \`*\' in
the same column as the star of the opening delimiter.

Examples of boxed comments are:

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.nf
.na
/**********************
 * Comment in a box!! *
 **********************/

       /*
        * A different kind of scent,
        * for a different kind of comment.
        */
.in -5
.ad
.fi

.B indent\fR attempts to leave boxed comments exactly as they are found
in the source file.  Thus the indentation of the comment is unchanged,
and its length is not checked in any way.  The only alteration made is
that an embedded tab character may be converted into the appropriate
number of spaces.

If the \`-bbb\' option is specified, all such boxed comments will be
preceded by a blank line, unless such a comment is preceded by code.

Comments which are not boxed comments may be formatted, which means that
the line is broken to fit within a right margin and left-filled with
whitespace.  Single newlines are equivalent to a space, but blank lines
(two or more newlines in a row) are taken to mean a paragraph break.
Formatting of comments which begin after the first column is enabled
with the \`-fca\' option.  To format those beginning in column one,
specify \`-fc1\'.  Such formatting is disabled by default.

The right margin for formatting defaults to 78, but may be changed with
the \`-lc\' option.  If the margin specified does not allow the
comment to be printed, the margin will be automatically extended for the
duration of that comment.  The margin is not respected if the comment is
not being formatted.

If the comment begins a line (i.e., there is no program text to its
left), it will be indented to the column it was found in unless the
comment is within a block of code.  In that case, such a comment will be
aligned with the indented code of that block (unless the comment began
in the first column).  This alignment may be affected by the \`-d\'
option, which specifies an amount by which such comments are moved to