The basename utility deletes any prefix ending with the last slash / character present in string (after first stripping trailing slashes), and a suffix, if given. The suffix is not stripped if it is identical to the remaining characters in string. The resulting filename is written to the standard output. A non-existent suffix is ignored. If -a is specified, then every argument is treated as a string as if basename were invoked with just one argument. If -s is specified, then the suffix is taken as its argument, and all other arguments are treated as a string.
The dirname utility deletes the filename portion, beginning with the last slash / character to the end of string (after first stripping trailing slashes), and writes the result to the standard output.
.Ex -std basename dirname
The following line sets the shell variable FOO to /usr/bin.