Feature or enhancement

GNU getopt supports options with optional arguments. For example GNU grep can be used with option --color=auto and with just --color. Unix getopt does not need it, because it stops after encountering first nonoption argument, but GNU getopt needs it to support options intermixed with positional arguments. getopt.gnu_getopt() needs it for the same reason.

Neither optparse nor argparse directly support such kind of optional arguments. It can be supported in optparse with custom callback, but support of optional arguments in argparse is non-standard. In future I'm planning to add support of such kind of optional arguments in argparse, and maybe in optparse.

Linked PRs

• gh-126374: Add support of options with optional arguments in the getopt module #126375