#!/usr/bin/perl -w
use strict;
use IO::File;
my @files = qw/file1 file2 file3/;
my @fhs = map{IO::File->new($_)||die "$_: $!"} @files;
print while $_ = join '', map{scalar <$_>||''} @fhs;
__END__


#!/usr/bin/perl -w
use strict;
use IO::File;
my $limit = 2000;
my @files = qw/file1 file2 file3/;
my @fhs = map{IO::File->new($_)||die "$_: $!"} @files;
for(1 .. $limit) {
    $_ = join '', map{scalar <$_>||''} @fhs or last;
    print;
}
__END__