./regex.pl Input.file '##(.*?)_kxx' 'KO$1'


##</code><code>##


#!/usr/bin/perl

use strict;


while(<DATA>){
  $_ =~ s/$ARGV[0]/$ARGV[1]/g;
  print $_;
}

__DATA__
|Chlre4|328957|pg._10_#_1
|Chlre4|28893|est.pg.C_80374
|Chlre5|338325|pm.pg._10_#_4


##</code><code>##


regex.pl '\|(\d+)\|' "#$1#"