dirname

dirname
dirname
	Example of dirname command
Developer(s)	Various open-source and commercial developers
Operating system	Unix, Unix-like, IBM i
Platform	Cross-platform
Type	Command
License	coreutils: GPLv3+

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.

The version in GNU Core Utilities was written by David MacKenzie and Jim Meyering.^[1] The command is available for Windows via UnxUtils,^[2] and is in IBM i.^[3]

Usage

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

$ dirname /home/martin/docs/base.wiki
/home/martin/docs

$ dirname /home/martin/docs/
/home/martin

$ dirname base.wiki
.

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.

dirname: return the directory portion of a pathname – Shell and Utilities Reference, The Single UNIX Specification, Version 5 from The Open Group
dirname(1) – Linux User Commands Manual
dirname(1) – OpenBSD General Commands Manual

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Categories Standard Unix programs Unix SUS2008 utilities List

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