[kdtsh]

Depends on what you need to optimise for. Being able to navigate a text file efficiently (i.e. not character-by-character using arrow keys), cut and paste text, save/rename/backup files, and sometimes even to do a diff from within your text editor, are all skills I’ve found very useful. I’m an Emacs user on my own desktop, but if you run Linux servers in this kind of environment and you or your team doesn’t manage them yourselves, then the best you can assume you have is Vim, or maybe Vi. If all you’ve got is SSH, it helps to be able to do this stuff without wanting to pull your hair out. Even watching some co-workers stumble through the use of Vim can be painful enough.