#!/usr/bin/perl

use strict;
use warnings;

 my $filename = 'dir/people.txt';
 
 open(my $fh_out, '>', $filename) or die "Could not open file out '$filename' $!";
 open(my $fh_in, '<', $filename) or die "Could not open file in'$filename' $!";

 # Read in line at a time
 while( my $line = <$fh_in> ) {

    # If the file start with blank line replace it with these headers
   if ( $line =~ /^\S/ ) {

       print $fh_out, "Name, City, State, Zip";
       
   }
 }
 close $fh_in;
 close $fh_out;