Dirname

dirname is a shell command for extracting the directory path portion of a path; without the last name. The command is specified in the Single UNIX Specification and is primarily used in shell scripts.

dirname
Developers	Various open-source and commercial developers
Written in	C
Operating system	Unix, Unix-like, IBM i
Platform	Cross-platform
Type	Command
License	coreutils: GPLv3+

The version in GNU Core Utilities was written by David MacKenzie and Jim Meyering.^[1] The command is available for Windows as part of the GnuWin32 project^[2] and UnxUtils^[3] and is in IBM i.^[4]

Usage

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

Examples

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
.

Performance

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.

See also

• basename – Shell command for extracting the last name from a path
• List of POSIX commands