/usr/bin/dirname

Usage: /usr/bin/dirname [OPTION] NAME...
Output each NAME with its last non-slash component and trailing slashes
removed; if NAME contains no /'s, output '.' (meaning the current directory).

  -z, --zero
         end each output line with NUL, not newline
      --help
         display this help and exit
      --version
         output version information and exit

Examples:
  /usr/bin/dirname /usr/bin/          -> "/usr"
  /usr/bin/dirname dir1/str dir2/str  -> "dir1" followed by "dir2"
  /usr/bin/dirname stdio.h            -> "."

Report bugs to: <bug-coreutils@gnu.org>.
GNU coreutils home page: <https://www.gnu.org/software/coreutils/>
General help using GNU software: <https://www.gnu.org/gethelp/>
Full documentation <https://www.gnu.org/software/coreutils/dirname>
or available locally via: info '(coreutils) dirname invocation'