etags(1)                           GNU Tools                          etags(1)

       etags, ctags - generate tag file for Emacs, vi

       etags [-aCDGIRVh] [-i file] [-l language]
       [-o tagfile] [-r regexp] [--parse-stdin=file]
       [--append] [--no-defines] [--globals] [--no-globals] [--include=file]
       [--ignore-indentation] [--language=language] [--members] [--no-members]
       [--output=tagfile] [--regex=regexp] [--no-regex] [--help] [--version]
       file ...

       ctags [-aCdgIRVh] [-BtTuvwx] [-l language]
       [-o tagfile] [-r regexp] [--parse-stdin=file]
       [--append] [--backward-search] [--cxref] [--no-defines] [--globals]
       [--no-globals] [--ignore-indentation] [--language=language] [--members]
       [--no-members] [--output=tagfile] [--regex=regexp] [--update] [--help]
       [--version] file ...

       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, Forth, HTML, LaTeX, Emacs Lisp/Common Lisp, Lua,
       Makefile, Pascal, Perl, PHP, 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.  If the tag
       table is in /dev or is the standard output, however, the file names are
       made relative to the working directory.  Files specified with absolute
       file names will be recorded with absolute file names.  Files generated
       from a source file--like a C file generated from a source Cweb
       file--will be recorded with the name of the source file.  Compressed
       files are supported using gzip, bzip2, and xz.  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.

       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

       -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.

              In C and derived languages, create tags for function
              declarations, and create tags for extern variables unless
              --no-globals is used.  In Lisp, create tags for (defvar foo)

       -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.

              Create tag entries for global variables in Perl and Makefile.
              This is the default in C and derived languages.

              Do not tag global variables in C and derived languages.
              Typically this reduces the file size by one fourth.

       -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.  Only etags accepts this option.

       -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 intermixed 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).

              Create tag entries for variables that are members of structure-
              like constructs in PHP.  This is the default for C and derived

              Do not tag member variables.

              Only tag packages in Ada files.

              May be used (only once) in place of a file name on the command
              line.  etags will read from standard input and mark the produced
              tags as belonging to the file FILE.

       -o tagfile, --output=tagfile
              Explicit name of file for tag table; for etags only, a file name
              of - means standard output; overrides default TAGS or tags.
              (But ignored with -v or -x.)

       -r regexp, --regex=regexp

              Make tags based on regexp matching for the files following this
              option, in addition to the tags made with the standard parsing
              based on language. May be freely intermixed with filenames and
              the -R option.  The regexps are cumulative, i.e., each such
              option will add to the previous ones.  The regexps are of one of
              the forms:

              where tagregexp is used to match the tag.  It should not match
              useless characters.  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.  The following character escape sequences
              are supported: \a, \b, \d, \e, \f, \n, \r, \t, \v, which
              respectively stand for the ASCII characters BEL, BS, DEL, ESC,
              FF, NL, CR, TAB, VT.
              The modifiers are a sequence of 0 or more characters among i,
              which means to ignore case when matching; m, which means that
              the tagregexp will be matched against the whole file contents at
              once, rather than line by line, and the matching sequence can
              match multiple lines; and s, which implies m and means that the
              dot character in tagregexp matches the newline char as well.
              The separator, which is / in the examples, can be any character
              different from space, tab, braces and @.  If the separator
              character is needed inside the regular expression, it must be
              quoted by preceding it with \.
              The optional {language} prefix means that the tag should be
              created only for files of language language, and ignored
              otherwise.  This is particularly useful when storing many
              predefined regexps in a file.
              In its second form, regexfile is the name of a file that
              contains a number of arguments to the --regex= option, one per
              line.  Lines beginning with a space or tab are assumed to be
              comments, and ignored.

              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]*\
              \|PROCEDURE\|PROCESS\|TYPE\)[ \t]+\([^ \t(]+\)/\3/'

              Tag TCL files (this last example shows the usage of a
              --lang=none --regex='/proc[ \t]+\([^ \t]+\)/\1/'

              A regexp can be preceded by {lang}, thus restricting it to match
              lines of files of the specified language.  Use etags --help to
              obtain a list of the recognized 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 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.

       -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.

       -x, --cxref
              Instead of generating a tag file, write a cross reference (in
              cxref format) to standard output.  Only ctags accepts this

       -h, -H, --help
              Print usage information.  Followed by one or more
              --language=LANG prints detailed information about how tags are
              created for LANG.

       -V, --version
              Print the current version of the program (same as the version of
              the emacs etags is shipped with).

       `emacs' entry in info; GNU Emacs Manual, Richard Stallman.
       cxref(1), emacs(1), vgrind(1), vi(1).

       Copyright (C) 1992, 1999, 2001-2015 Free Software Foundation, Inc.

       Permission is granted to make and distribute verbatim copies of this
       document provided the copyright notice and this permission notice are
       preserved on all copies.

       Permission is granted to copy and distribute modified versions of this
       document 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
       document into another language, under the above conditions for modified
       versions, except that this permission notice may be stated in a
       translation approved by the Free Software Foundation.

GNU Tools                          23nov2001                          etags(1)