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       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 --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.

              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

              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 languages.

              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

              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

              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
              --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 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).


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


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