#!/usr/bin/perl
use Time::HiRes qw(usleep nanosleep);

my $blanked = 0;
open (IN, "xscreensaver-command -watch |");
while (<IN>) {
    if (m/^(BLANK|LOCK)/) {
        if (!$blanked) {
            system "wmctrl -s 1";
            $blanked = 1;
        }
    } elsif (m/^UNBLANK/) {
        usleep(100000);
        system "wmctrl -s 0";
        $blanked = 0;
    }
}