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etags(1)                           GNU Tools                          etags(1)



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] [--no-globals] [--include=file]
       [--ignore-indentation] [--language=language] [--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] [--defines] [--forward-search]
       [--globals] [--ignore-indentation] [--language=language] [--members]
       [--output=tagfile] [--regex=regexp] [--typedefs] [--typedefs-and-c++]
       [--update] [--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, HTML, LaTeX, Emacs Lisp/Common Lisp, Lua, makefile, Pascal, Perl,
       PHP, Postscript, Python, Prolog, Scheme and most assembler-like syntax-
       es.  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 work-
       ing  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.  The programs recognize the  language
       used  in an input file based on its file name and contents.  The --lan-
       guage 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 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.  Since this  is  the  default  behavior  of
              etags, only ctags accepts this option.

       -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.  Since this is the de-
              fault behavior of ctags, only etags accepts this option.

       --globals
              Create tag entries for global variables in C, C++, Objective  C,
              Java,  and  Perl.   Since this is the default behavior of etags,
              only ctags accepts this option.

       --no-globals
              Do not tag global variables.  Typically this  reduces  the  file
              size  by  one  fourth.   Since  this  is the default behavior of
              ctags, only etags accepts this option.

       -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 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).

       --members
              Create tag entries for variables that are members of  structure-
              like constructs in C++, Objective C, Java.

       --no-members
              Do not tag member variables.  This is the default behavior.

       --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  op-
              tion  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 use-
              ful  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 respec-
              tively 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 char-
              acter is needed inside the regular expression, it must be quoted
              by preceding it with \.
              The optional {language} prefix means that the tag should be cre-
              ated 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 con-
              tains 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]*\(ARCHITECTURE\|\     CONFIGURA-
              TION\) +[^ ]* +OF/' --regex='/[ \t]*\ \(ATTRIBUTE\|ENTITY\|FUNC-
              TION\|PACKAGE\( BODY\)?\                                \|PROCE-
              DURE\|PROCESS\|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
              behavior 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 behavior 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.

       -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.   Followed  by  one  or  more  --lan-
              guage=LANG prints detailed information about how tags are creat-
              ed 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) 1999, 2001, 2002, 2003,  2004,  2005,  2006,  2007,  2008
       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 per-
       mission notice identical to this one.

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




GNU Tools                          23nov2001                          etags(1)