depends on what you mean by "on the command line".

I personally find python most useful to learn, especially in combination with invoking a real editor to edit multi-line commands:

bash has C-x C-e and the `fc` buildin, other shells have equivalents.

https://www.gnu.org/software/bash/manual/bash.html#index-edi...

I have extensively used awk and it's lacking when mid size problems become larger projects.

I also have used perl quite a bit, and if you love the "sigil" you can become very, very happy with perl. I personally never go warm with sigil, I have developed sigil-itis, so to speak.