sub parse_commands
{
    my ($filename) = @_;

    my $fh = IO::File->new($filename) || die ...;
    while (<$fh>)
    {
        # All commands being with a letter and must be the first character
        next if /^[^A-Za-z]/;

        # A command is space-delimited and must be on one line.
        # We want to deal with the entire command in uppercase.
        my ($command, @line) = split /\s+/, uc;

        unless (exists $DispatchTable{$command})
        {
            warn "'$command' isn't a valid command.\n";
            next;
        }

        push @commands, [$command, \@line];
    }

    return \@commands;
}