file1
2013,06,21      2013,06,24
2013,06,23      2013,06,28
2013,06,08      2013,06,10
2013,06,23      2013,06,24
2013,06,13      2013,06,18
2013,06,29
2013,06,17      2013,06,19
2013,06,13      2013,06,18
2013,06,29
2013,06,06      2013,06,10
2013,06,10      2013,06,26
2013,06,23      2013,06,29
2013,06,06      2013,06,10

##</code><code>##

#!/usr/bin/perl
# 
use strict;
use warnings;
use Date::Calc qw( Delta_Days );
my $cnt = 0;

open (my $file, '<', (@ARGV)) or die $!;
while (<$file>) {
	my @dates = split '\t', $_;
	$cnt++;
#	printf "%-10s %-10s\n",
#	$dates[0], 
#	$dates[1];

my @dates1 = ();
my @dates2 = ();

push (@dates1, $dates[0]);
push (@dates2, $dates[1]);

my $diff = Delta_Days(@dates1, @dates2);
print $diff, "\n";
#printf "%-12s %-12s\n",
#@dates1, 
#@dates2;

}
close $file;

print $cnt, "\n";
exit;