gistfile1.txt

$ cat main.p6
multi sub MAIN ($mode where 'css') { say "You're in the CSS option"; }

multi sub MAIN () { say "You didn't enter an option"; }

multi sub MAIN ($mode, $arg) { say "You entered two command line arguments"; }

multi sub MAIN ($mode) { say "Unknown mode $mode"; }

$ ./perl6 main.p6
You didn't enter an option
$ ./perl6 main.p6  foobar
Unknown mode foobar
$ ./perl6 main.p6  bar baz
You entered two command line arguments
$ ./perl6 main.p6 css
You're in the CSS option
$