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

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-edit_002dand_002dexecute_002dcommand-_0028C_002dx-C_002de_0029 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.