CTAGS(1) Commands and Applications CTAGS(1)
ctags - create a tags file
ctags [-BFadtuwvx] [-f tagsfile] name...
Ctags makes a tags file for ex(1) from the specified C, Pascal, For-
tran, YACC, lex, and lisp sources. A tags file gives the locations of
specified objects in a group of files. Each line of the tags file con-
tains the object name, the file in which it is defined, and a search
pattern for the object definition, separated by white-space. Using the
tags file, ex(1) can quickly locate these object definitions. Depend-
ing upon the options provided to ctags, objects will consist of subrou-
tines, typedefs, defines, structs, enums and unions.
-B use backward searching patterns (?...?).
-F use forward searching patterns (/.../) (the default).
-a append to tags file.
-d create tags for #defines that don't take arguments; #defines
that take arguments are tagged automatically.
-f Places the tag descriptions in a file called tagsfile. The
default behaviour is to place them in a file called tags.
-t create tags for typedefs, structs, unions, and enums.
-u update the specified files in the tags file, that is, all refer-
ences to them are deleted, and the new values are appended to
the file. (Beware: this option is implemented in a way which is
rather slow; it is usually faster to simply rebuild the tags
-v An index of the form expected by vgrind(1) is produced on the
standard output. This listing contains the object name, file
name, and page number (assuming 64 line pages). Since the out-
put will be sorted into lexicographic order, it may be desired
to run the output through sort(1). Sample use:
ctags -v files | sort -f > index
vgrind -x index
-w suppress warning diagnostics.
-x ctags produces a list of object names, the line number and file
name on which each is defined, as well as the text of that line
and prints this on the standard output. This is a simple index
which can be printed out as an off-line readable function index.
Files whose names end in .c or .h are assumed to be C source files and
are searched for C style routine and macro definitions. Files whose
names end in .y are assumed to be YACC source files. Files whose names
end in .l are assumed to be lisp files if their first non-blank charac-
ter is ';', '(', or '[', otherwise, they are treated as lex files.
Other files are first examined to see if they contain any Pascal or
Fortran routine definitions, and, if not, are searched for C style def-
The tag main is treated specially in C programs. The tag formed is
created by prepending M to the name of the file, with the trailing .c
and any leading pathname components removed. This makes use of ctags
practical in directories with more than one program.
Yacc and lex files each have a special tag. Yyparse is the start of
the second section of the yacc file, and yylex is the start of the sec-
ond section of the lex file.
tags default output tags file
Ctags exits with a value of 1 if an error occurred, 0 otherwise.
Duplicate objects are not considered errors.
This command was ported from FreeBSD source code for distribution with
Recognition of functions, subroutines and procedures for FORTRAN and
Pascal is done is a very simpleminded way. No attempt is made to deal
with block structure; if you have two Pascal procedures in different
blocks with the same name you lose. Ctags doesn't understand about
The method of deciding whether to look for C, Pascal or FORTRAN func-
tions is a hack.
Ctags relies on the input being well formed, and any syntactical errors
will completely confuse it. It also finds some legal syntax confusing;
for example, since it doesn't understand #ifdef's (incidentally, that's
a feature, not a bug), any code with unbalanced braces inside #ifdef's
will cause it to become somewhat disoriented. In a similar fashion,
multiple line changes within a definition will cause it to enter the
last line of the object, rather than the first, as the searching pat-
tern. The last line of multiple line typedef's will similarly be
The Ctags command appeared in 3.0BSD.
GNO October 1997 CTAGS(1)
Man(1) output converted with