Yeah. That's what I think I want to learn but phonegap etc. were making me feel like maybe it was becoming more obsolete. From what you said, and what I have heard others say though I think that isn't true. I just want to learn something that will continue to be relevant for a long time.
Now there are similar tools out there, but none were exactly like what I wanted.
Try it out. If you're interested, my main use is for `xcodebuild`.
It has it's own site here: https://ackchyually.sh