#!/usr/bin/perl
$ln = shift(@ARGV);
while (@ARGV) {
  $fn = shift; 
  open(IN,"$fn"); 
  @in = <IN>; 
  $in[$ln] = "%".$in[0];
  close IN;            
  print STDERR "$fn:\t",$#in," lines\n";
  open(IN,">$fn"); 
  print IN @in;
  close IN;
}