Timed alert program

timer.pl

#!/icg/bin/perl
use Getopt::Std;
my %opt;
getopts('t:', \%opt);

my $z = shift or die;
if    ($z =~ s/m$//) { $z *= 60 }
elsif ($z =~ s/h$//) { $z *= 3600 }
elsif ($z =~ s/s$//) { $z *= 1 }
elsif ($z =~ /\D/) { die "Usage: timer [ 30[s] | 5m | 1h ] message...\n" }

my $timeout = $opt{t} * 1000 || int($z * 33.333);
$timeout = 1000 if $timeout < 1000;

@ARGV = ('Timer expired') unless @ARGV;
exit if fork();
sleep $z;
exec "notify-send", "-t", $timeout, @ARGV;
die "exec notify-send: $!";