getopt

getopt [options] [--] parameters

getopt parses command-line options for shell scripts, handling both short (-v) and long (--verbose) option formats. It normalizes option order, handles bundled short options (-abc), and separates options from arguments.The enhanced getopt (util-linux version) supports long options, optional arguments, and proper handling of arguments with spaces. Use getopt -T to test if the enhanced version is available.Output is typically evaluated with eval set -- to update the script's positional parameters with the normalized options.

-o, --options SHORT

Short options to recognize (single letters). Colon after letter means required argument, double colon means optional.

Long options to recognize (comma-separated). Colon rules same as short options.

Name to use in error messages

Suppress error messages

Allow long options with single dash

Test for enhanced getopt

In the options string:- f - flag with no argument- f: - option with required argument- f:: - option with optional argument

The original BSD getopt is limited and doesn't support long options. Always test for enhanced getopt with -T. Optional arguments must be attached directly (--opt=arg, not --opt arg).

getopt dates back to early Unix systems. The enhanced version in util-linux was developed to overcome limitations of the original, adding long option support and proper quoting for arguments with special characters.

getopts(1), bash(1)

Source code · Documentation