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NAME

       etags, ctags - generate tag file for Emacs, vi

SYNOPSIS

       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 ...

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, 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 and bzip2.  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, --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.

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

       --no-globals
              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).

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

       --no-members
              Do not tag member variables.

       --packages-only
              Only tag packages in Ada files.

       --parse-stdin=file
              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:
                   [{language}]/tagregexp/[nameregexp/]modifiers
                   @regexfile

              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]*\
              \(ATTRIBUTE\|ENTITY\|FUNCTION\|PACKAGE\( BODY\)?\
              \|PROCEDURE\|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 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 option.

       -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).

SEE ALSO

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

COPYING

       Copyright (C) 1992, 1999, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011
       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.