use strict;
use warnings;

open (T1, "t1") or die;
my @file1 = <T1>;
my @file2 = <DATA>;
my @file;

while (@file1 and @file2) {
  push @file, (shift @file1, shift @file2);
}

push @file, @file1 or @file2; #catch any leftover

while (my $line = shift @file) {
   #do 'things' with it
    print $line;
}

__END__
file1
file1
file1
file1

##</code><code>##

Useless use of private array in void context at junk line 13.
file2
file1
file2
file1
file2
file1
file2
file1
file2
file3, kidding... file2

##</code><code>##

use strict;
use warnings;

$/ = "****";

my @array;

while (<DATA>) {
     chomp;
     push @array, $_;
     $/= "####";
}

print "@array";

__END__
stuff****more
stuff####less

##</code><code>##

$ perl junk
stuff more
stuff less