#!/usr/bin/perl  
use strict -w;  

my $DOC="file.in";
my $OUTDOC="file.out";  

open (INFILE,'$DOC'||die "Could Not Open $DOC");
open (OUTFILE,'>>$OUTDOC'||die "Could Not Open $OUTDOC");  

while(<INFILE>)
{
  if(/aa|bb|cc|dd|ee|ff|gg|hh|ii|jj|kk|ll|mm|nn|oo|pp|qq|rr|ss|tt|uu|vv|ww|xx|yy|zz/i)
   {
     ????????????    
    print OUTFILE $_;
   }
   else
   { 
    print OUTFILE $_;
   }
}
 
close INFILE;
close OUTFILE;