Hi,
another way is to compute the difference between NOW and starttime and to sleep this time in seconds.

#!/usr/local/bin/perl -w
use strict;
use Time::Local;
use POSIX qw(ctime difftime mktime);

my $starttime = '08.12.02 03:00:00';
my $nowtime = time; #time in sec since 1970
my $sTime = 0;
my $sleepSec = 0;

#parsing the input (start) time
if ($starttime =~ /^\s*(\d{1,2})\.(\d{1,2})\.(\d{2})\s+(\d{1,2})\:(\d{
+1,2})\:(\d{1,2})\s*$/) {
  #  mktime(sec,min,hr,day,month,year)
  #  month (0..11); year = 0 => 1900 , year = 100 => 2000
  $sTime = mktime($6,$5,$4,$1,$2-1,100+$3); 
}

print "Now-Date   = ", ctime($nowtime);
print "Start-Date = ", ctime($sTime);

$sleepSec = difftime($sTime,$nowtime);
if ($sleepSec>0) {
  print "Want to sleep : $sleepSec seconds\n"; 
  # sleep ($sleepSec);
} else {
  print "Shit I missed my starttime...\n";
}
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