#!/usr/bin/perl
use warnings;
use strict;
use Date::Parse;

# 799107 

my $data = '';

while ( <DATA> ) {
	# print $_;
	$data = $_;
	chomp ($data);
		if ($data =~ /^DATE:\s+(\w{3}, \d+ \w{3} \d{4} \d\d:\d\d:\d\d) ([+-]\d{4})/ ) {
		my $date = $1;   	# Don't do this; check existence of $1 
		my $zone = $2;	 	# and $2 before you try to use them!
		print "'Date' found: $date which converts to: ";
		my $time = str2time($date);
		print "$time Zone Offset: $zone\n";
		print "\t Restringified: " . localtime($time) . "\n"; # reconvert, solely as a check on above
	}
}

=head OUTPUT
'Date' found: Sat, 9 Feb 2008 17:14:18 which converts to: 1202595258 Zone Offset: -0730
         Restringified: Sat Feb  9 17:14:18 2008
'Date' found: Sun, 10 Feb 2008 04:23:55 which converts to: 1202635435 Zone Offset: +0400
         Restringified: Sun Feb 10 04:23:55 2008
=cut

__DATA__
SUBJECT: test
FROM: John Smith
DATE: Sat, 9 Feb 2008 17:14:18 -0730
TO: Joe Doe
additional for demo only
DATE:  Sun, 10 Feb 2008 04:23:55 +0400