dirname

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dirname is a standard UNIX computer program. When dirname is given a pathname, it will delete any suffix beginning with the last slash ('/') character and return the result. dirname is described in the Single UNIX Specification and is primarily used in shell scripts.

Usage[edit]

The Single UNIX Specification specification for dirname is.

 dirname NAME

For example:

 $ dirname /usr/home/carpetsmoker/dirname.wiki
   /usr/home/carpetsmoker

Performance[edit]

Since dirname accepts only one operand, its usage within the inner loop of shell scripts can be detrimental to performance. Consider

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

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

 echo "${file%/*}";

See also[edit]

External links[edit]