#!usr/bin/perl

use strict;

my $in_file;
my $out_file;
my $answer;
my $pattern;
my $replacement;

# This program prompts user for an input file, an output file, a search pattern and a replacement string, then executes the search and replacement between the two files.

print "Enter the in_put file";
chomp($in_file = <STDIN>);
print "Enter the out_put file";
chomp($out_file = <STDIN>);
print "Enter the pattern";
chomp($pattern = <STDIN>);
print "Enter the replacement";
chomp($replacement = <STDIN>);

open (IN, "$in_file") || die "not a rockstar today"; 
die "will not overwrite $out_file" if -e $out_file;
open (OUT, ">$out_file") || die "not a rockstar today";

 while (<IN>) { # 
	S/$pattern/$replacement/g;	
	print OUT $_;

 } # end while

close (IN);
close (OUT);