1etags(1) GNU Tools etags(1)
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6 etags, ctags - generate tag file for Emacs, vi
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9 etags [-aCDGIQRVh] [-i file] [-l language]
10 [-o tagfile] [-r regexp] [--parse-stdin=file]
11 [--append] [--no-defines] [--globals] [--no-globals]
12 [--no-line-directive] [--include=file] [--ignore-indentation]
13 [--language=language] [--members] [--no-members] [--output=tagfile]
14 [--class-qualify] [--regex=regexp] [--no-regex] [--help] [--version]
15 file ...
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17 ctags [-aCdgIQRVh] [-BtTuvwx] [-l language]
18 [-o tagfile] [-r regexp] [--parse-stdin=file]
19 [--append] [--backward-search] [--cxref] [--no-defines] [--globals]
20 [--no-globals] [--no-line-directive] [--ignore-indentation]
21 [--language=language] [--members] [--no-members] [--class-qualify]
22 [--output=tagfile] [--regex=regexp] [--update] [--help] [--version]
23 file ...
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26 The etags program is used to create a tag table file, in a format un‐
27 derstood by emacs(1); the ctags program is used to create a similar ta‐
28 ble in a format understood by vi(1). Both forms of the program under‐
29 stand the syntax of C, Objective C, C++, Java, Fortran, Ada, Cobol, Er‐
30 lang, Forth, Go, HTML, LaTeX, Emacs Lisp/Common Lisp, Lua, Makefile,
31 Pascal, Perl, Ruby, PHP, PostScript, Python, Prolog, Scheme and most
32 assembler-like syntaxes. Both forms read the files specified on the
33 command line, and write a tag table (defaults: TAGS for etags, tags for
34 ctags) in the current working directory. Files specified with relative
35 file names will be recorded in the tag table with file names relative
36 to the directory where the tag table resides. If the tag table is in
37 /dev or is the standard output, however, the file names are made rela‐
38 tive to the working directory. Files specified with absolute file
39 names will be recorded with absolute file names. Files generated from
40 a source file--like a C file generated from a source Cweb file--will be
41 recorded with the name of the source file. Compressed files are sup‐
42 ported using gzip, bzip2, and xz. The programs recognize the language
43 used in an input file based on its file name and contents. The --lan‐
44 guage switch can be used to force parsing of the file names following
45 the switch according to the given language, overriding guesses based on
46 filename extensions.
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49 Some options make sense only for the vi style tag files produced by
50 ctags; etags does not recognize them. The programs accept unambiguous
51 abbreviations for long option names.
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53 -a, --append
54 Append to existing tag file. (For vi-format tag files, see also
55 --update.)
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57 -B, --backward-search
58 Tag files written in the format expected by vi contain regular
59 expression search instructions; the -B option writes them using
60 the delimiter "?", to search backwards through files. The de‐
61 fault is to use the delimiter "/", to search forwards through
62 files. Only ctags accepts this option.
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64 --declarations
65 In C and derived languages, create tags for function declara‐
66 tions, and create tags for extern variables unless --no-globals
67 is used. In Lisp, create tags for (defvar foo) declarations.
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69 -D, --no-defines
70 Do not create tag entries for C preprocessor constant defini‐
71 tions and enum constants. This may make the tags file much
72 smaller if many header files are tagged.
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74 --globals
75 Create tag entries for global variables in Perl and Makefile.
76 This is the default in C and derived languages.
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78 --no-globals
79 Do not tag global variables in C and derived languages. Typi‐
80 cally this reduces the file size by one fourth.
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82 --no-line-directive
83 Ignore #line preprocessor directives in C and derived languages.
84 The default is to honor those directives, and record the tags as
85 if the file scanned was the one named in the #line directive.
86 This switch is useful when the original file named by #line is
87 no longer available.
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89 -i file, --include=file
90 Include a note in the tag file indicating that, when searching
91 for a tag, one should also consult the tags file file after
92 checking the current file. Only etags accepts this option.
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94 -I, --ignore-indentation
95 Don't rely on indentation as much as we normally do. Currently,
96 this means not to assume that a closing brace in the first col‐
97 umn is the final brace of a function or structure definition in
98 C and C++.
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100 -l language, --language=language
101 Parse the following files according to the given language. More
102 than one such options may be intermixed with filenames. Use
103 --help to get a list of the available languages and their de‐
104 fault filename extensions. The "auto" language can be used to
105 restore automatic detection of language based on the file name.
106 The "none" language may be used to disable language parsing al‐
107 together; only regexp matching is done in this case (see the
108 --regex option).
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110 --members
111 Create tag entries for variables that are members of structure-
112 like constructs in PHP. This is the default for C and derived
113 languages.
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115 --no-members
116 Do not tag member variables.
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118 --packages-only
119 Only tag packages in Ada files.
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121 --parse-stdin=file
122 May be used (only once) in place of a file name on the command
123 line. etags will read from standard input and mark the produced
124 tags as belonging to the file FILE.
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126 -Q, --class-qualify
127 Qualify tag names with their class name in C++, ObjC, Java, and
128 Perl. This produces tag names of the form class::member for C++
129 and Perl, class(category) for Objective C, and class.member for
130 Java. For Objective C, this also produces class methods quali‐
131 fied with their arguments, as in foo:bar:baz:more.
132
133 -o tagfile, --output=tagfile
134 Explicit name of file for tag table; for etags only, a file name
135 of - means standard output; overrides default TAGS or tags.
136 (But ignored with -v or -x.)
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138 -r regexp, --regex=regexp
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140 Make tags based on regexp matching for the files following this
141 option, in addition to the tags made with the standard parsing
142 based on language. May be freely intermixed with filenames and
143 the -R option. The regexps are cumulative, i.e., each such op‐
144 tion will add to the previous ones. The regexps are of one of
145 the forms:
146 [{language}]/tagregexp/[nameregexp/]modifiers
147 @regexfile
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149 where tagregexp is used to match the tag. It should not match
150 useless characters. If the match is such that more characters
151 than needed are unavoidably matched by tagregexp, it may be use‐
152 ful to add a nameregexp, to narrow down the tag scope. ctags
153 ignores regexps without a nameregexp. The syntax of regexps is
154 the same as in emacs. The following character escape sequences
155 are supported: \a, \b, \d, \e, \f, \n, \r, \t, \v, which respec‐
156 tively stand for the ASCII characters BEL, BS, DEL, ESC, FF, NL,
157 CR, TAB, VT.
158 The modifiers are a sequence of 0 or more characters among i,
159 which means to ignore case when matching; m, which means that
160 the tagregexp will be matched against the whole file contents at
161 once, rather than line by line, and the matching sequence can
162 match multiple lines; and s, which implies m and means that the
163 dot character in tagregexp matches the newline char as well.
164 The separator, which is / in the examples, can be any character
165 different from space, tab, braces and @. If the separator char‐
166 acter is needed inside the regular expression, it must be quoted
167 by preceding it with \.
168 The optional {language} prefix means that the tag should be cre‐
169 ated only for files of language language, and ignored otherwise.
170 This is particularly useful when storing many predefined regexps
171 in a file.
172 In its second form, regexfile is the name of a file that con‐
173 tains a number of arguments to the --regex= option, one per
174 line. Lines beginning with a space or tab are assumed to be
175 comments, and ignored.
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177 Here are some examples. All the regexps are quoted to protect
178 them from shell interpretation.
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180 Tag the DEFVAR macros in the emacs source files:
181 --regex='/[ \t]*DEFVAR_[A-Z_ \t(]+"\([^"]+\)"/'
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183 Tag VHDL files (this example is a single long line, broken here
184 for formatting reasons):
185 --language=none --regex='/[ \t]*\(ARCHITECTURE\|\ CONFIGURA‐
186 TION\) +[^ ]* +OF/' --regex='/[ \t]*\ \(ATTRIBUTE\|ENTITY\|FUNC‐
187 TION\|PACKAGE\( BODY\)?\ \|PROCE‐
188 DURE\|PROCESS\|TYPE\)[ \t]+\([^ \t(]+\)/\3/'
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190 Tag TCL files (this last example shows the usage of a tagreg‐
191 exp):
192 --lang=none --regex='/proc[ \t]+\([^ \t]+\)/\1/'
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194 A regexp can be preceded by {lang}, thus restricting it to match
195 lines of files of the specified language. Use etags --help to
196 obtain a list of the recognized languages. This feature is par‐
197 ticularly useful inside regex files. A regex file contains one
198 regex per line. Empty lines, and those lines beginning with
199 space or tab are ignored. Lines beginning with @ are references
200 to regex files whose name follows the @ sign. Other lines are
201 considered regular expressions like those following --regex.
202 For example, the command
203 etags --regex=@regex.file *.c
204 reads the regexes contained in the file regex.file.
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206 -R, --no-regex
207 Don't do any more regexp matching on the following files. May
208 be freely intermixed with filenames and the --regex option.
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210 -u, --update
211 Update tag entries for files specified on command line, leaving
212 tag entries for other files in place. Currently, this is imple‐
213 mented by deleting the existing entries for the given files and
214 then rewriting the new entries at the end of the tags file. It
215 is often faster to simply rebuild the entire tag file than to
216 use this. Only ctags accepts this option.
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218 -v, --vgrind
219 Instead of generating a tag file, write index (in vgrind format)
220 to standard output. Only ctags accepts this option.
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222 -x, --cxref
223 Instead of generating a tag file, write a cross reference (in
224 cxref format) to standard output. Only ctags accepts this op‐
225 tion.
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227 -h, -H, --help
228 Print usage information. Followed by one or more --lan‐
229 guage=LANG prints detailed information about how tags are creat‐
230 ed for LANG.
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232 -V, --version
233 Print the current version of the program (same as the version of
234 the emacs etags is shipped with).
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238 "emacs" entry in info; GNU Emacs Manual, Richard Stallman.
239 cxref(1), emacs(1), vgrind(1), vi(1).
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243 Copyright 1992, 1999, 2001-2019 Free Software Foundation, Inc.
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245 Permission is granted to make and distribute verbatim copies of this
246 document provided the copyright notice and this permission notice are
247 preserved on all copies.
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249 Permission is granted to copy and distribute modified versions of this
250 document under the conditions for verbatim copying, provided that the
251 entire resulting derived work is distributed under the terms of a per‐
252 mission notice identical to this one.
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254 Permission is granted to copy and distribute translations of this docu‐
255 ment into another language, under the above conditions for modified
256 versions, except that this permission notice may be stated in a trans‐
257 lation approved by the Free Software Foundation.
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261GNU Tools 23nov2001 etags(1)