$ perl -s timeoverlap.961234.pl
Start: Sun Mar 25 06:53:28 2012
Start: 0
unit6;449
unit2;1014
End: Sun Mar 25 06:53:34 2012
End: 6

$ perl -s timeoverlap.961234.pl -withDateTime
Start: Sun Mar 25 06:53:37 2012
Start: 1
unit6;447
unit2;1013
End: Sun Mar 25 06:53:37 2012
End: 1