use strict;
use warnings;

use FileHandle;

my @files   = ("test1.dat", "test2.dat", "test3.dat");
my @handles;

@handles = map { FileHandle->new ($_) } @files;

my $while = 1;

while ($while)
{
    my @lines;
  
    for ( @handles )
    {
        $while = 0, last if $_->eof;
        
        $line = $_->getline;
        chomp $line;
        push @lines, $line;
    }

    print join ("\t", @lines), "\n";
}