More or less repeating some of the advice from prev posts, but
1. if you have an upcoming requirement to use one of those skills, then do that course, its the sane thing.
2. if not, perl is much more widely applicable and you can do it at/for work (if allowed) and also at home. Its part of the std install.
With any tech subject, if you don't use it, especially after just having done the course, it'll fade fast. Tech skills need reinforcement.
You are extremely unlikely to have access to a Veritas cluster to work/play with unless it's part of your job...