$ 04_02_validate_derive --help
A simple to use, efficient, and full-featured Command Line Argument Parser
Usage: 04_02_validate_derive[EXE] <PORT>
Arguments:
<PORT> Network port to use
Options:
-h, --help Print help
-V, --version Print version
$ 04_02_validate_derive 22
PORT = 22
$ 04_02_validate_derive foobar
? failed
error: invalid value 'foobar' for '<PORT>': `foobar` isn't a port number
For more information, try '--help'.
$ 04_02_validate_derive 0
? failed
error: invalid value '0' for '<PORT>': port not in range 1-65535
For more information, try '--help'.