Provided by: xemacs21-bin_21.4.24-12build3_amd64 
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 un‐
derstand 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 command 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 absolute 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 following the switch according to the given language, overriding 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 contain regular expression search instructions; the
-B 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 function declarations, and create tags for extern
variables unless --no-globals is used.
-d, --defines
Create tag entries for C preprocessor constant definitions and enum constants, too. This is the
default behavior for etags.
-D, --no-defines
Do not create tag entries for C preprocessor constant 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 de‐
fault behavior for etags.
-G, --no-globals
Do not tag global variables. Typically this reduces 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 in‐
termixed with filenames. Use --help to get a list of the available languages and their default
filename extensions. The `auto' language can be used to restore automatic detection of language
based on the file name. The `none' language may be used to disable language parsing altogether;
only regexp matching is done in this case (see the --regex option).
-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 default `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 language. When using --regex, case is signif‐
icant, 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 reg‐
exps 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 tagreg‐
exp, 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\( BODY\)?\ \|PROCE‐
DURE\|PROCESS\|TYPE\)[ \t]+\([^ \t(]+\)/\3/'
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 restriciting it to match lines of files of the specified
language. Use etags --help to obtain a list of the recognised languages. This feature is partic‐
ularly 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 beginning with @ are references to
regex files whose name follows the @ sign. Other lines are considered 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 ac‐
cepts 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 existing entries for the given files and
then rewriting 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 option.
-v, --vgrind
Instead of generating a tag file, write index (in vgrind format) to standard output. Only ctags
accepts this option.
-w, --no-warn
Suppress warning messages about duplicate entries. The etags program does not check for duplicate
entries, so this option is not allowed with it.
-x, --cxref
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 versions 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 conditions for modified versions, except that this permission notice may be included in transla‐
tions approved by the Free Software Foundation instead of in the original English.
GNU Tools 14gen2001 etags(1)