Prezto for zsh has pretty good command line completion and a lot of plugins which are either on by default or available for you to flip the switch on. It's taught me some nifty bits of git, gpg and some others. https://github.com/sorin-ionescu/prezto
I personally prefer working on a command line because it's _more_ discoverable to me than most gui's. This did take some getting used to though. The approach is different.
The worry over making dangerous mistakes is understandable. That said I have made very few big ones after a bit of learning, and it has also helped me _avoid_ making dangerous mistakes by facilitating the automation of otherwise delicate or involved tasks which would be unpleasant to click and type through.
I personally prefer working on a command line because it's _more_ discoverable to me than most gui's. This did take some getting used to though. The approach is different.
The worry over making dangerous mistakes is understandable. That said I have made very few big ones after a bit of learning, and it has also helped me _avoid_ making dangerous mistakes by facilitating the automation of otherwise delicate or involved tasks which would be unpleasant to click and type through.