NAME

basename, dirname — separate path components

SYNOPSIS

DESCRIPTION

Write the final or pre-final segments of paths, stripping suffix, if matched, to the standard output stream, separated by newlines.

Trailing slashes are removed; basename then removes everything up to the final slash, and dirname removes everything following it, then strips trailing ones. If a path doesn't contain slashes, basename outputs it verbatim, and dirname outputs ".".

These are strictly string operations, and do not depend on the filesystem state.

OPTIONS

-a, --multiple

Accept multiple paths.

-s, --suffix=suffix

Accept multiple paths and set suffix.

-z, --zero

Separate output lines with null bytes instead of newlines.

EXAMPLES

$ basename /bin/sort
sort
$ basename include/stdio.h .h
stdio
$ basename -s .h include/stdio.h /usr/include/stdlib.h
stdio
stdlib
$ basename -a dir/file1 dir/dir2/file2 file3
file1
file2
file3

$ dirname /usr/local/bin/
/usr/local
$ dirname dir1/str dir2/str
dir1
dir2
$ dirname stdio.h
.

STANDARDS

Conforms to IEEE Std 1003.1-2024 (“POSIX.1”), with no special processing for //. -zas and multiple paths are extensions, originating from the GNU system, also present in FreeBSD.

HISTORY

basename appeared, fully formed, save for lacking a newline at the end, in Version 7 AT&T UNIX, as basename(1) – "strip filename affixes":

CB-UNIX at or before 2.1 contains unrelated shell implementations (newline included) of both. CB-UNIX was, among others, the basis for AT&T System III UNIX, where it first saw light outside AT&T.

These implementations continued to evolve, growing peculiar preservational handling of the // prefix, until AT&T System V Release 3 UNIX, which IEEE Std 1003.2-1992 (“POSIX.2”) standardised, requiring that handling on systems where //-prefixed paths are different from /-prefixed ones. 4.3BSD-Reno includes both, without //.