Dirname

The Single UNIX Specification is: dirname path. The required argument, path, is a file path string.

The command reports the directory path portion of a path ignoring any trailing slashes.

$ dirname /path/to/filename.ext /path/to $ dirname /path/to/ /path $ dirname filename.ext .

Since the command accepts only one operand, its usage within the inner loop of a shell script can be detrimental to performance. Consider:

while read file; do dirname "$file" done < some-input

The above causes a separate process invocation for each line of input. For this reason, shell substitution is typically used instead:

echo "${file%/*}";

Or, if relative pathnames need to be handled as well:

if [ -n "${file##*/*}" ]; then echo "." else echo "${file%/*}"; fi

Note that these handle trailing slashes differently than dirname.