Use of uninitialized value $previoustime in subtraction (-) at soonix.pl line 15.
1447773471 at MWE.pl line 22.
before sleeping: time = 1447773471, $time = 1447773471,
after sleeping:  time = 1447773481, $time = 1447773471,
1447773471 at MWE.pl line 22.
1447773481 at MWE.pl line 22.
before sleeping: time = 1447773481, $time = 1447773481,
after sleeping:  time = 1447773491, $time = 1447773481,
1447773481 at MWE.pl line 22.
1447773491 at MWE.pl line 22.
before sleeping: time = 1447773491, $time = 1447773491,
after sleeping:  time = 1447773501, $time = 1447773491,
1447773491 at MWE.pl line 22.
1447773501 at MWE.pl line 22.