#!/usr/bin/perl -l

use strict;
use warnings;

my @fh=map {
    open my $fh, '<', $_ or die "Can't open `$_': $!\n";
    $fh } @ARGV;

no warnings 'uninitialized';
print while $_=join '',
  map { chomp(my $line=<$_>); $line } @fh,

__END__