use Date::Manip; use Text::CSV; my $csv = Text::CSV->new; while (<>) { $csv->parse($_); my @f = $csv->fields; $f[7] = UnixDate $f[7], "%Y-%m-%d-%H.%M.%S.0000"; $csv->combine(@f); print $csv->string . "\n"; } #### ID,21,11814,1,11989,150,Y,2012-10-25-23.36.25.0000,TEST ID,22,11814,1,11989,150,Y,2012-10-25-23.36.25.0000,TEST