etags



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  un-
       derstood by emacs(1); the ctags program is used to create a similar ta-
       ble in a format understood by vi(1).  Both forms of the program  under-
       stand the syntax of C, Objective C, C++, Java, Fortran, Ada, Cobol, Er-
       lang,  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 guess-
       es 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  de-
              fault  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  declara-
              tions,  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 defini-
              tions 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 reduces the file
              size by one fourth.  This is the default 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  col-
              umn  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  de-
              fault  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 al-
              together; 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
              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 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, augmented with inter-
              vals 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]*\(ARCHITECTURE\|\     CONFIGURA-
              TION\) +[^ ]* +OF/ --regex=/[ \t]*\ \(ATTRIBUTE\|ENTITY\|FUNC-
              TION\|PACKAGE\( BODY\)?\                       \|PROCEDURE\|PRO-
              CESS\|TYPE\)[ \t]+\([^ \t(]+\)/\3/

              Tag TCL files (this last example shows the usage  of  a  tagreg-
              exp):
              --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 recognised languages.  This feature is par-
              ticularly 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 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 imple-
              mented 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 op-
              tion.

       -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, 2001 Free Software Foundation, Inc.

       Permission  is  granted to copy, distribute and/or modify this document
       under the terms of the GNU Free Documentation License, Version  1.1  or
       any  later  version  published by the Free Software Foundation; with no
       Invariant Sections, with no Front-Cover Texts, and no Back-Cover Texts.

       This  document  is  part of a collection distributed under the GNU Free
       Documentation License.  If you want to distribute this  document  sepa-
       rately  from  the collection, you can do so by adding a copy of the li-
       cense to the document, as described in section 6  of  the  license.   A
       copy  of  the  license  is included in the gfdl(1) man page, and in the
       section entitled "GNU Free Documentation License" in the Emacs  manual.



GNU Tools                          08apr2001                          etags(1)

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