socketpair

parallel_request.pl

#!/usr/bin/perl

use strict;
use warnings;
use Socket;
use IO::Handle;

my @callback;

for my $host (@ARGV) {
    socketpair(my $child, my $parent, AF_UNIX, SOCK_STREAM, PF_UNSPEC)
        or die $!;

    $child->autoflush(1);
    $parent->autoflush(1);

    if (my $pid = fork) {
        close $parent;
        push @callback, sub {
            local $/ = undef;
            chomp(my $line = <$child>);
            print "$host: $line";
            close $child;
            waitpid($pid, 0);
        };
    } elsif (defined $pid) {
        close $child;
        close STDOUT;
        open  STDOUT, '>&' . fileno($parent);
        close $parent;
        exec "squidclient -h $host -p 8080 mgr:5min | grep 'syscalls.sock.writes'";
        exit;
    } else {
        die $!;
    }
}

$_->() for @callback;