You probably want something like this:

use warnings;
use strict;

my $cmd = 'netstat';
my $pattern = qr/WXP-DPBG8BS\s*:\s*(\d+)/;

open my $PIPE, '-|', $cmd or die "Could not open the pipe from '$cmd' 
+because:$!";

while ( <$PIPE> ) {
    if ( /$pattern/ ) {
        print "port found: $1\n";
        }
    }

close $PIPE or warn $! ? "Error closing $cmd pipe: $!"
                       : "Exit status $? from $cmd";
[download]