etags(1) GNU Tools etags(1)NAME
etags, ctags - generate tag file for Emacs, vi
SYNOPSIS
etags [-aCDGImRVh] [-i file] [-l language]
[-o tagfile] [-r regexp]
[--append] [--no-defines] [--no-globals] [--include=file]
[--ignore-indentation] [--language=language] [--members]
[--output=tagfile] [--regex=regexp] [--no-regex]
[--ignore-case-regex=regexp] [--help] [--version] file ...
ctags [-aCdgImRVh] [-BtTuvwx] [-l language]
[-o tagfile] [-r regexp]
[--append] [--backward-search] [--cxref] [--defines]
[--forward-search] [--globals] [--ignore-indentation]
[--language=language] [--members] [--output=tagfile]
[--regex=regexp] [--ignore-case-regex=regexp] [--typedefs]
[--typedefs-and-c++] [--update] [--no-warn] [--help]
[--version] file ...
DESCRIPTION
The `etags' program is used to create a tag table file, in
a format understood by emacs(1); the `ctags' program is
used to create a similar table in a format understood by
vi(1). Both forms of the program understand the syntax of
C, Objective C, C++, Java, Fortran, Ada, Cobol, Erlang,
LaTeX, Emacs Lisp/Common Lisp, makefiles, Pascal, Perl,
Postscript, Python, Prolog, Scheme and most assembler-like
syntaxes. Both forms read the files specified on the com
mand line, and write a tag table (defaults: `TAGS' for
etags, `tags' for ctags) in the current working directory.
Files specified with relative file names will be recorded
in the tag table with file names relative to the directory
where the tag table resides. Files specified with abso
lute file names will be recorded with absolute file names.
The programs recognize the language used in an input file
based on its file name and contents. The --language
switch can be used to force parsing of the file names fol
lowing the switch according to the given language, over
riding guesses based on filename extensions.
OPTIONS
Some options make sense only for the vi style tag files
produced by ctags; etags does not recognize them. The
programs accept unambiguous abbreviations for long option
names.
-a, --append
Append to existing tag file. (For vi-format tag
files, see also --update.)
-B, --backward-search
Tag files written in the format expected by vi con
tain regular expression search instructions; the -B
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option writes them using the delimiter `?', to
search backwards through files. The default is to
use the delimiter `/', to search forwards through
files. Only ctags accepts this option.
--declarations
In C and derived languages, create tags for func
tion declarations, and create tags for extern vari
ables unless --no-globals is used.
-d, --defines
Create tag entries for C preprocessor constant def
initions and enum constants, too. This is the de
fault behavior for etags.
-D, --no-defines
Do not create tag entries for C preprocessor con
stant definitions and enum constants. This may
make the tags file much smaller if many header
files are tagged. This is the default behavior for
ctags.
-g, --globals
Create tag entries for global variables in C, C++,
Objective C, Java, and Perl. This is the default
behavior for etags.
-G, --no-globals
Do not tag global variables. Typically this re
duces the file size by one fourth. This is the de
fault behavior for ctags.
-i file, --include=file
Include a note in the tag file indicating that,
when searching for a tag, one should also consult
the tags file file after checking the current file.
This options is only accepted by etags.
-I, --ignore-indentation
Don't rely on indentation as much as we normally
do. Currently, this means not to assume that a
closing brace in the first column is the final
brace of a function or structure definition in C
and C++.
-l language, --language=language
Parse the following files according to the given
language. More than one such options may be inter
mixed with filenames. Use --help to get a list of
the available languages and their default filename
extensions. The `auto' language can be used to re
store automatic detection of language based on the
file name. The `none' language may be used to dis
able language parsing altogether; only regexp
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matching is done in this case (see the --regex op
tion).
-m, --members
Create tag entries for variables that are members
of structure-like constructs in C++, Objective C,
Java.
-M, --no-members
Do not tag member variables. This is the default
behavior.
--packages-only
Only tag packages in Ada files.
-o tagfile, --output=tagfile
Explicit name of file for tag table; overrides de
fault `TAGS' or `tags'. (But ignored with -v or
-x.)
-r regexp, --regex=regexp, --ignore-case-regex=regexp
Make tags based on regexp matching for each line of
the files following this option, in addition to the
tags made with the standard parsing based on lan
guage. When using --regex, case is significant,
while it is not with --ignore-case-regex. May be
freely intermixed with filenames and the -R option.
The regexps are cumulative, i.e. each option will
add to the previous ones. The regexps are of the
form:
/tagregexp[/nameregexp]/
where tagregexp is used to match the lines that
must be tagged. It should not match useless char
acters. If the match is such that more characters
than needed are unavoidably matched by tagregexp,
it may be useful to add a nameregexp, to narrow
down the tag scope. ctags ignores regexps without
a nameregexp. The syntax of regexps is the same as
in emacs, augmented with intervals of the form
\{m,n\}, as in ed or grep.
Here are some examples. All the regexps are quoted
to protect them from shell interpretation.
Tag the DEFVAR macros in the emacs source files:
--regex='/[ \t]*DEFVAR_[A-Z_ \t(]+"\([^"]+\)"'
Tag VHDL files (this example is a single long line,
broken here for formatting reasons):
--language=none --regex='/[ \t]*\(ARCHITECTURE\|\
CONFIGURATION\) +[^ ]* +OF/' --regex='/[ \t]*\
\(ATTRIBUTE\|ENTITY\|FUNCTION\|PACKAGE\( BODY\)?\
\|PROCEDURE\|PROCESS\|TYPE\)[ \t]+\([^ \t(]+\)/\3/'
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Tag TCL files (this last example shows the usage of
a tagregexp):
--lang=none --regex='/proc[ \t]+\([^ \t]+\)/\1/'
A regexp can be preceded by {lang}, thus restricit
ing it to match lines of files of the specified
language. Use etags --help to obtain a list of the
recognised languages. This feature is particularly
useful inside regex files. A regex file contains
one regex per line. Empty lines, and those lines
beginning with space or tab are ignored. Lines be
ginning with @ are references to regex files whose
name follows the @ sign. Other lines are consid
ered regular expressions like those following
--regex.
For example, the command
etags --regex=@regex.file *.c
reads the regexes contained in the file regex.file.
-R, --no-regex
Don't do any more regexp matching on the following
files. May be freely intermixed with filenames and
the --regex option.
-t, --typedefs
Record typedefs in C code as tags. Since this is
the default behaviour of etags, only ctags accepts
this option.
-T, --typedefs-and-c++
Generate tag entries for typedefs, struct, enum,
and union tags, and C++ member functions. Since
this is the default behaviour of etags, only ctags
accepts this option.
-u, --update
Update tag entries for files specified on command
line, leaving tag entries for other files in place.
Currently, this is implemented by deleting the ex
isting entries for the given files and then rewrit
ing the new entries at the end of the tags file.
It is often faster to simply rebuild the entire tag
file than to use this. Only ctags accepts this op
tion.
-v, --vgrind
Instead of generating a tag file, write index (in
vgrind format) to standard output. Only ctags ac
cepts this option.
-w, --no-warn
Suppress warning messages about duplicate entries.
The etags program does not check for duplicate en
tries, so this option is not allowed with it.
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Instead of generating a tag file, write a cross
reference (in cxref format) to standard output.
Only ctags accepts this option.
-h, -H, --help
Print usage information.
-V, --version
Print the current version of the program (same as
the version of the emacs etags is shipped with).
SEE ALSO
`emacs' entry in info; GNU Emacs Manual, Richard Stallman.
cxref(1), emacs(1), vgrind(1), vi(1).
COPYING
Copyright (c) 1999 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.
Permission is granted to copy and distribute modified ver
sions of this manual under the conditions for verbatim
copying, provided that the entire resulting derived work
is distributed under the terms of a permission notice
identical to this one.
Permission is granted to copy and distribute translations
of this manual into another language, under the above con
ditions for modified versions, except that this permission
notice may be included in translations approved by the
Free Software Foundation instead of in the original En
glish.
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