On Tue, Dec 21, 2010 at 09:40:42PM +0200, Roland RoLaNd wrote: > original data: > > 01,01368,2010-12-02,09:07:00,Pass > 01,01368,2010-12-02,10:54:00,Pass > 01,01368,2010-12-02,13:07:04,Pass > 01,01368,2010-12-02,18:54:01,Pass > 01,01368,2010-12-03,09:02:00,Pass > 01,01368,2010-12-03,13:53:00,Pass > 01,01368,2010-12-03,16:07:00,Pass > the only thing missing is to find a way to just take the > earliest time of each day. You may use mktime(datespec) (see man awk) to covert date and time into comparable integers. Mihai