DIRNAME(3) Linux Programmer's Manual DIRNAME(3)
dirname, basename - Parse pathname components
char *dirname(char *path);
char *basename(char *path);
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 base-
name 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 if you need to preserve the
pathname string, copies should be passed to these functions. Furthermore, dirname and
basename may return pointers to statically allocated memory which may be overwritten by
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"
"/" "/" "/"
"." "." "."
".." "." ".."
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);
Both dirname and basename return pointers to null-terminated strings.
In versions of glibc up to and including 2.2.1, dirname does not correctly handle path-
names with trailing '/' characters, and generates a segmentation violation if given a NULL
GNU 2000-12-14 DIRNAME(3)