sub add {
    print "added\n";
}

sub remove {
    print "removed\n";
}

my $dt = {
   'add'    => \&add ,
   'remove' => \&remove
};

my $cmd = "add";
if (defined $dt->{$cmd}) {
    $dt->{$cmd}();
} else {
    print "command not found: ", $cmd, "\n";
}