As I write this, plerdall --help does this:

jjohn@www:~$ plerdall --help
Unknown option: help
Can't start /usr/local/bin/plerdall: I can't find a Plerd config file in /home/jjohn/plerd.conf,
/home/jjohn/conf/plerd.conf, /home/jjohn/.plerd, or in /usr/local/bin/../conf/plerd.conf, and no other location was specified as a command-line argument. at /usr/local/share/perl/5.24.1/Plerd/Util.pm line 39.

I have observed that --help is a widely adopted convention of many apps. plerdall should consider implementing this.