Forum .LRN Q&A: Learn basic use of unix
It might or might not be a good choice for you, and it's certainly out of date now, but a dozen years or so ago now when I was first learning Unix, I personally found UNIX For the Impatient to be excellent. If you haven't already, I recommend asking around for good "intro to unix" sorts of books. Plenty of other folks here could probably give recommendations...
In some very unusual cases (e.g., an OpenACS Bootcamp or training class) it can be possible to be productive with OpenACS while knowing nearly nothing at all about using Unix ("Um, 'ls', did that have something to do with listing files?"). But that's unusual, and definitely isn't the case for you, because you're installing OpenACS and dotLRN yourself from scratch, and presumably will be maintaining it, doing development work, etc.
In general, learning basic unix use will serve you very well in the future, and the sooner you learn it, the better off you'll be.