for (@files) {  #
    open my $fh, '<', $_ or 
      (warn "$_: $!\n"), next;
    push @first_lines, scalar <$fh>;
}

##</code><code>##

#!/usr/bin/perl

use strict;
use warnings;

die "Usage: $0 <net>\n" unless @ARGV == 1;
# Rudimentary check on the argument
(my $net=shift) =~ s/\.0+$/./
  or die "Supply an IP of the form <#.#.#.0>\n";

print 'Begun pings at ' . localtime, "\n";
my @p;
open $p[@p], '-|', "ping -w 5 -c 5 $net$_"
  or die "Couldn't start ping for $net$_: $!\n" for 1..255;
undef $/;
print map <$_>, @p;

__END__

##</code><code>##

my @p = map {
    open my $fh, '-|', "ping -w 5 -c 5 $net$_"
      or die "Couldn't start ping for $net$_: $!\n"; 
    $fh } 1..255;