my $cmd = "iwlist wlan0 scan";

open my $pipe, '-|', $cmd or die "(E) could not execute: $cmd: $!\n";
        while ( my $line = <$pipe> ) {
                next if $line !~ m/ESSID/;         # replace the "| grep ESSID" in the $cmd

                print Dumper($line);
        }
close $pipe;