#!usr/bin/perl
use strict;
use warnings;

open ONE, '<' ,'one.txt' or die "Ooops $!";
open TWO, '<' ,'two.txt' or die "Ooops $!";

my $EOFseenfile1=0;
my $EOFseenfile2=0;

# Loop finished when EOF has been seen at least once
# on both files.

while (not $EOFseenfile1 or not $EOFseenfile2) #go until both EOF seen
{
   my $line1 = <ONE>;
   my $line2 = <TWO>;
   
   chomp ($line1, $line2);

   print "$line1 \t $line2\n";

   if (eof ONE)
   {
      seek ONE,0,0;
      $EOFseenfile1++;
   }
  
   if (eof TWO)
   {
      seek TWO,0,0;
      $EOFseenfile2++;
   }  
}
__END__
file 1 line 1 	 file 2 line 1
file 1 line 2 	 file 2 line 2
file 1 line 3 	 file 2 line 3
file 1 line 1 	 file 2 line 4
file 1 line 2 	 file 2 line 5
file 1 line 3 	 file 2 line 6
file 1 line 1 	 file 2 line 7
file 1 line 2 	 file 2 line 8

file 1 has 3 lines
file 2 has 8 lines