Print NAME with its trailing /component removed; if NAME contains no /'s, output `.' (meaning the current directory).

--help

display this help and exit

--version

output version information and exit

dirname /usr/bin/sort

Output "/usr/bin".

dirname stdio.h

Output ".".

The full documentation for dirname is maintained as a Texinfo manual. If the info and dirname programs are properly installed at your site, the command

info coreutils aqdirname invocationaq

should give you access to the complete manual.