Thanks for both suggestions.

I used the "print join" suggestion to see what was going on and used single quotes in the string to prevent GetOptions splitting the log command.

I then saw that the script was tring to open the log file with ">>$log", which of course failed with a pipe for a log file. I removed the ">>" and it now works as desired.

Is there a foolproof way to only add the ">>" if the log file is a file rather than a pipe?

Is it as simple as checking for the pipe character at the start of the string? Something like:

$logfilename = $log;
if (substr($log, 0, 1) ne "|") {
  $logfilename = ">>" . $log;
}
if (!open STDOUT, $logfilename) { die "Can't write to $logfilename: $!
+";}
[download]

Thanks,

R.