Thank you all. From the advice I got here, I looked closer at fork(), and found it is a perfect fit for what I want. I did some test scripts, and found that I can fork() and wait for the return while using the children to all print their output to a common (opened before the fork) file with the first line the PID of the process. Then I can sort it to get the output from each and check for errors.

This approach has proven to be simple (complicated until I got a little more familiar) and very effective. The result is that I can run all of them at once and wait for the response.

In case anyone wanted to see, this is the test script. The file that it opens contains a list of servers to hit, and the script just echos the host name followed by a 30 second wait both executed on the remote host. 

#!/usr/bin/perl
use strict;
use warnings;
use Net::SSH qw(ssh);


my %serverPid;
my ($testkey, $testvalue);
die("Could not open file list: $!") unless
    open(FHServerList, "<", "./servers");
die("Could not open log file: $!") unless
    open(FHlog, ">>", "./log");
    
    
while(<FHServerList>) {
    my $serverName = $_;
    chomp($serverName);
    my $pid = fork();
    if($pid == '0'){
        #Child process
        print FHlog (ssh($serverName, "hostname; sleep 30"));
        exit(0)
    }
    else {
        $serverPid{$serverName} = $pid;
    }
}

while(($testkey, $testvalue) = each %serverPid) {
    waitpid($testvalue, 0);
        print ("Done with $testkey\n");
    }

close(FHServerList);
exit()

[download]

It is not super clean (it will implode on itself if the fork fails), but it is functional, and will get cleaned up as I work on the full 'real' script.

Thanks again for the help guys.

In reply to Re: Do I need threads? by TechFly
in thread Do I need threads? by TechFly

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