sub help {
   print(@_);
   print(" This is help?\n");
}

sub list {
   print("This is list\n");
}

our $commands = {
    'help' => \&help,
    'list' => \&list,
};

while (<STDIN>) {
    chomp;
    if ((my $name) = ($_ =~ /^(\w+)/)) {
        if (defined $commands->{$name}) {
            $commands->{$name}->($_);
        } else {
            print "I Don't understand $name\n";
        }
    }

}