Thanks.

"Do you really want to send the output to a file named STDOUT?"

Not really. What I was trying to do is have a medium-sized script be able to alternate between writing output to a file or to stdout itself, depending on an option.

. . .

if (defined($opt{'o'})) {
    $output = $opt{'o'};
    $output =~ s/[\0-\x1f]//g;
    if ($output =~ /^([-\/\w\.]+)$/) {
        $output = $1;
    } else {
        die("Bad path or file name: '$output'\n");
    }
} else {
    $output = '/dev/stdout';
}

. . .

open(my $out, $mode, $output)
        or die("Could not open '$output' for writing: $!\n");
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That way I can use the same print statements for either purpose. I presume there is a better way for all that, however.