#!/usr/bin/perl -w

use strict;

my @data;

# define a hash of changes to be made
my %change = (  HEAL  => 'NOTE Medical:',
                HIST  => 'NOTE Biography:',
                EDUC  => 'NOTE Educated:',
                RESI  => 'NOTE Resided:',
                OCCU  => 'NOTE Occupation:',
              );

# accept input via three mechanisms
# if no file specified here:
my $file = '';

# then look for a command line argument here:
$file = shift @ARGV unless $file;

# if we still have no file to process
# enter interactive mode here:
unless ($file) {
    print "Please enter a file to process: ";
    chomp($file = <>);
}

# get the data
open (FILE, "<$file") or die "Unable to open $file: $!";
@data = <FILE>;
close FILE;

# make the changes
for (@data) {
    for my $key (keys %change) {
        s/$key/$change{$key}/g;
    }
}

# print the changes to a new file with the same name
# as the original plus a .new suffix.
open (FILE, ">$file.new") or die "Unable to write $file.new: $!";
print FILE @data;
close FILE;

print "Munged $file no worries!\n";