use strict; open(INFILE, "PSR_Date.txt"); open(OUTFILE, ">PSR_OutputDate.txt"); while () { $line = $_; $line =~ s/(\d{4})-(\d{2})-(\d{2})\s\d{2}:\d{2}:\d{2}/\2\/\3\/\1/g; print OUTFILE "$line"; } close INFILE; print "Done!\n"; chomp($pause = ); _DATA_ OD44202,07/01/2015,08/19/2019,08/27/2019,1,07/01/2015,06/30/2019,2015-06-20 00:00:00 OD44202,07/01/2015,08/19/2019,08/27/2019,1,07/01/2015,06/30/2019,2015-06-20 00:00:00 OD44202,07/01/2015,08/19/2019,08/27/2019,1,07/01/2015,06/30/2019,2015-06-20 00:00:00 OD44202,07/01/2015,08/19/2019,08/27/2019,1,07/01/2015,06/30/2019,2015-06-20 00:00:00 _OUTPUT_ OD44202,07/01/2015,08/19/2019,08/27/2019,1,07/01/2015,06/30/2019,06/20/2015 OD44202,07/01/2015,08/19/2019,08/27/2019,1,07/01/2015,06/30/2019,06/20/2015 OD44202,07/01/2015,08/19/2019,08/27/2019,1,07/01/2015,06/30/2019,06/20/2015 OD44202,07/01/2015,08/19/2019,08/27/2019,1,07/01/2015,06/30/2019,06/20/2015