BASENAME(3)                                         Linux Programmer's Manual                                        BASENAME(3)



NAME
       basename, dirname - parse pathname components

SYNOPSIS
       #include <libgen.h>

       char *dirname(char *path);

       char *basename(char *path);

DESCRIPTION
       Warning: there are two different functions basename() - see below.

       The  functions  dirname()  and basename() break a null-terminated pathname string into directory and filename components.
       In the usual case, dirname() returns the string up to, but not including, the final '/', and basename() returns the  com-
       ponent following the final '/'.  Trailing '/' characters are not counted as part of the pathname.

       If  path  does not contain a slash, dirname() returns the string "." while basename() returns a copy of path.  If path is
       the string "/", then both dirname() and basename() return the string "/".  If path is a NULL  pointer  or  points  to  an
       empty string, then both dirname() and basename() return the string ".".

       Concatenating the string returned by dirname(), a "/", and the string returned by basename() yields a complete pathname.

       Both  dirname() and basename() may modify the contents of path, so it may be desirable to pass a copy when calling one of
       these functions.

       These functions may return pointers to statically allocated memory which may be overwritten by subsequent calls.   Alter-
       natively,  they  may return a pointer to some part of path, so that the string referred to by path should not be modified
       or freed until the pointer returned by the function is no longer required.

       The following list of examples (taken from SUSv2) shows the strings returned by dirname() and  basename()  for  different
       paths:

       path         dirname    basename
       "/usr/lib"    "/usr"    "lib"
       "/usr/"       "/"       "usr"
       "usr"         "."       "usr"
       "/"           "/"       "/"
       "."           "."       "."
       ".."          "."       ".."

RETURN VALUE
       Both dirname() and basename() return pointers to null-terminated strings.  (Do not pass these pointers to free(3).)

CONFORMING TO
       POSIX.1-2001.

NOTES
       There  are  two different versions of basename() - the POSIX version described above, and the GNU version, which one gets
       after

           #define _GNU_SOURCE
           #include <string.h>

       The GNU version never modifies its argument, and returns the empty string when path has a trailing slash, and in particu-
       lar also when it is "/".  There is no GNU version of dirname().

       With glibc, one gets the POSIX version of basename() when <libgen.h> is included, and the GNU version otherwise.

BUGS
       In the glibc implementation of the POSIX versions of these functions they modify their argument, and segfault when called
       with a static string like "/usr/".  Before glibc 2.2.1, the glibc version of dirname() did not correctly handle pathnames
       with trailing '/' characters, and generated a segfault if given a NULL argument.

EXAMPLE
           char *dirc, *basec, *bname, *dname;
           char *path = "/etc/passwd";

           dirc = strdup(path);
           basec = strdup(path);
           dname = dirname(dirc);
           bname = basename(basec);
           printf("dirname=%s, basename=%s\n", dname, bname);

SEE ALSO
       basename(1), dirname(1), feature_test_macros(7)

COLOPHON
       This  page  is  part of release 3.25 of the Linux man-pages project.  A description of the project, and information about
       reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.



GNU                                                        2009-03-30                                                BASENAME(3)