Different ways to create subcommands like in hg
or svn
with the exact command line interface and help output as shown in Remarks section.
http://stackoverflow.com/documentation/python/1382/parsing-command-line-arguments covers broader topic of arguments parsing.
Different ways to create subcommands like in hg
or svn
with the command line interface shown in the help message:
usage: sub <command>
commands:
status - show status
list - print list