Thanks much for the reply. I didn't expect an answer so fast or that it would provide the solution.

Though the example you gave doesn't work, maybe because of 'use strict;' , I did find a couple things that do work. If I did have a better understanding of Linux, I may have found the answer on my own. Just something I'll have to work on.

Here are a couple examples of what did work for me:

use strict;

if ( -t STDIN ) {
    print "This is what you're supposed to do ...\n";
    exit;
}

# or 

use POSIX qw(isatty);
if ( isatty(\*STDIN) ) {
    print "This is what you're supposed to do ...\n";
    exit;
}

while (<STDIN>) {
    print STDOUT "Add something to STDOUT".$_;
}
[download]

Thanks for the help. It wasn't a show-stopping feature, just trying to mitigate confusion by some users when the command is run and the cursor just sits there doing nothing.