When I run my script it runs okay, but there are major delays in the output. Each child runs a remote ssh command on the IPs listed in %hosts. The command can optionally take grep arguments. It seem like the last child gets priority in printing to STDOUT. What am I missing? Why don't all three children print nearly evenly and why the delays? The delays are as follows, I can open another window and watch directly on the remote server using tail -f, as the log file grows. But the output of my script is always 3-4 log entries behind. The log gets updated about every 10 seconds, so 40 seconds is a long time. Thanks, Aaron 
#!/usr/bin/perl
$|=1;
%hosts=(
        "host1" => "192.168.168.32",
        "host2" => "192.168.168.33",
        "host3" => "192.168.168.34"
);

$file = "/var/log/bluebolt/bluebolt.log";
$tail = "/usr/bin/tail";
$ssh = "/usr/bin/ssh";
$grep = "/bin/grep --color=always";


#die "Usage: $0 <file>\n" unless @ARGV;
if ($ARGV[0] eq "--help"){
        print "Usage $0 [pattern]\n";
        print "$0 will show all log files for App servers\n";
        print "$0 [pattern] will grep the log files for the pattern\n"
+;
        exit;
}

$SIG{CHLD} = 'IGNORE';
$SIG{INT} = sub {done("Received SIGINT")};
sub done {
        print "@_\n";
        exit;
}
foreach $key (keys %hosts) {
        if(fork){
                #parent process does nothing
        } else {
                #child process does all the work
                #add any grep commands here
                if ($ARGV[0]) {
                        if ($ARGV[1]) {
                                $command = "$ssh  $hosts{$key} $tail -
+f $file | $grep $ARGV[0] $ARGV[1]";
                        }else{
                                $command = "$ssh  $hosts{$key} $tail -
+f $file | $grep $ARGV[0]";
                        }
                } else {
                        $command = "$ssh $hosts{$key} $tail -f $file";
                }

                open (README, "$command |") or die "Couldn't fork: $!\
+n";
                select README;
                $|=1;
                while(<README>){
                        print STDOUT "$hosts{$key}: ";
                        print STDOUT $_;
                }
        }
}
while(1){sleep(5);}#parent process needs to wait for Ctrl-C

exit;

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In reply to why the long delays? by alager

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