#!/usr/bin/perl
while (<>)
{
   @in = split(/\n/,$_);
   foreach $line(@in)
   {
      if ( $line =~ m/^(.{4})(.*)$/ )
      {
        $p1=$1; $p2=$2; #save matches
        $p2 =~ s/./*/g;
        print "final=$p1$p2\n";
      }
   }
}