#!/usr/bin/perl -w
use strict;
use IO::Handle;
die "usage: $0 <files>\n" unless(@ARGV);
my @files=map {
	my $fh=new IO::Handle;
	open($fh,"<",$_) or die "open: $!";
	$fh
} @ARGV;
my $numleft=@files;
my ($field,$line);
while(1) {
	$line="";
	for(my $i=0;$i<@files;$i++) {
		$line.="\t" if($i);
		next unless($files[$i]);
		$field=$files[$i]->getline();
		if(defined($field)) {
			chomp $field;
			$line.=$field;
		} else {
			$files[$i]=undef;
			$numleft--;
		}
	}
	last if(0==$numleft);
	print "$line\n";
}