#! /usr/local/bin/perl5

$search_for = 'foo'; 
$replace_with = 'bar';

foreach $filename (@ARGV) {
   
   open(FILE, "$filename");
   @data = <FILE>;
   close(FILE);

   for($i = 0; $i < @data; $i++){
       @data[$i] =~ s/$search_for/$replace_with/g;
   }
  
   open(FILE, ">$filename");
   print FILE (@data);
   close(FILE);


}