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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 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.


       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.

       -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).


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