18.2 dirname: Strip last file name component

dirname prints all but the final slash-delimited component of each name. Slashes on either side of the final component are also removed. If the string contains no slash, dirname prints ‘.’ (meaning the current directory). Synopsis:

dirname [option] name…

name need not be a file name, but if it is, this operation effectively lists the directory that contains the final component, including the case when the final component is itself a directory.

Together, basename and dirname are designed such that if ‘ls "$name"’ succeeds, then the command sequence ‘cd "$(dirname "$name")"; ls "$(basename "$name")"’ will, too. This works for everything except file names containing a trailing newline.

POSIX allows the implementation to define the results if name is ‘//’. With GNU dirname, the result is ‘//’ on platforms where // is distinct from /, and ‘/’ on platforms where there is no difference.

The program accepts the following option. Also see Common options.

‘-z’ ¶

‘--zero’

Output a zero byte (ASCII NUL) at the end of each line, rather than a newline. This option enables other programs to parse the output even when that output would contain data with embedded newlines.

An exit status of zero indicates success, and a nonzero value indicates failure.

Examples:

# Output "/usr/bin".
dirname /usr/bin/sort
dirname /usr/bin//.//

# Output "dir1" followed by "dir2"
dirname dir1/str dir2/str

# Output ".".
dirname stdio.h