Check also Net::OpenSSH::Parallel.

I've come back to this now, and tried N:O:P. It makes it very simple, here's the core of the script:

for my $host (@hosts) {
    $pssh->add_host($host, user => $user);
}

$pssh->push('*', 'command', { stderr_to_stdout => 1 }, $cmd );
$pssh->run;
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My next problem is that I want to decorate the return from each host, to tell them apart. Perhaps something like this:

%) net.pl -c uptime kermit fozzy
kermit)  10:49:37 up 3 days, 21:38,  0 users,  load average: 1.00, 1.0
+1, 1.05
fozzy)   10:49:37 up 6 days, 21:08,  0 users,  load average: 1.00, 1.0
+1, 1.05
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I'm not sure how I would extend N:O:P to do this. Probably have to go back into N:O.

See my OP for an update, as I had a D'oh moment, and realized it was that easy.

-QM
--
Quantum Mechanics: The dreams stuff is made of

A pipe can be attached to the output stream:

$pssh->push('*', 'command', { stderr_to_stdout => 1,
                              stdout_file => ['|-', 'perl', '-ne', 'pr
+int "%HOST%$_\n"'] },
                              $cmd );
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Or the more efficient:

require POSIX;

my %fh;
for my $host (@hosts) {
  my $pid = open my $fh, '|-';
  if (not $pid) {
    while (<>) {
      print "$host) $_";
    }
    POSIX::_exit(0);
  }
  $fh{$host} = $fh;
  $pssh->add_host($host, default_stderr_fh => $fh, default_stdout_fh =
+> $fh);
}

$pssh->push('*', 'command', $cmd );
$pssh->run;

close $_ for values %fh;
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Note that lines comming from stderr and stdout may arrive intermixed. A more correct solution would be to use different filters for stderr and stdout.