Trivial Utilities

`pgrep`

The main program is quite simple:

        $rc = 1;  # No matches;

        if ($opt_I) {
          while (<STDIN>) { chomp; do_file($_) }
        } elsif (@ARGV) {
          do_file($_) for @ARGV;
        } else {
          do_file(\*STDIN);
        }
        exit $rc;

All the interesting work is in do_file