Probably the simplest thing to do is to test whether STDIN is connected to a tty, using the -t operator.

    sub prompt {
      -t STDIN and print "\n? ";
    }

  while ( prompt(), defined($_=<STDIN>) ) {
    chomp;
    print "$_\n";
  }
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jdporter
The 6th Rule of Perl Club is -- There is no Rule #6.