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       basename, dirname - parse pathname components


       #include <libgen.h>

       char *dirname(char *path);

       char *basename(char *path);


       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 component 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.  Alternatively, 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"
       "/"           "/"       "/"
       "."           "."       "."
       ".."          "."       ".."


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




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

           #define _GNU_SOURCE         /* See feature_test_macros(7) */
           #include <string.h>

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

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


       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.


           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);


       basename(1), dirname(1)


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