Thanks for this. Slackware used to have a shell builtin like this. I personally used it for tracking where in a database dump/import I was at-- if you've had to do this with any non-trivial db's you know what I mean.

+1 to this not being anything new. NULL is not a value, it is the absence of it-- a placeholder to represent that no value exists. If no value exists, surely it can't be equal to anything, including another NULL.

Brute force removal of files can lead to unexpected issues, especially when removing a log file from underneath a running process. You can mediate this a bit by using find to only remove 'old' files, in this example-- older than 5 days.

> (sudo) find /private/var/log/asl/* -mtime +5 -exec rm -rf {} \;

I use this personally to clear out my local development and test logs older than a day