my  @msgs = ("Thu Oct 18 21:26:36 2007: Time for all triggers in report period (300s): 1.330981s",
                 "Thu Oct 18 21:27:36 2007: Time for all triggers in report period (600s): 1.457271s",
                 "Thu Oct 18 21:28:36 2007: Time for all triggers in report period (60s): 1.340150s");

  for my $msg (@msgs) {
    if ($msg =~ /Time for all triggers in report period \((\d+)s\)/) {
       my $time = ${1};
       # Insert your logic here...
       if (  $time >= 600) { print "Time ($time) >= 600\n"; }
       elsif($time >= 300) { print "Time ($time) >= 300\n"; }
       elsif($time >= 60 ) { print "Time ($time) >= 60\n";  }
       else                { print "Time ($time) <  60\n"; }
    }
  }