my %options = (
...
  "decon"          => \&decon_server, 
); 
...
    die_usage()
       if (!GetOptions(%options)); 

##</code><code>##

my %options = (
...
  "decon"          => \my $do_decon_server, 
); 
...
    die_usage()
       if (!GetOptions(%options)); 
...
    if( $do_decon_server ) {
        decon_server();
    };