Vim

Before we get a decent open source integrated development environment, what else can you do?

But also perfect for small one-off files when you don't have the patience to setup said IDE.

vim's defaults are atrocious for the 21st century! Vundle is reasonable as an ad-hoc package manager, but it can't set fixed versions of packages:

Vimscript unit testing!!!

Ciro Santilli contributed a bit to this, and was even given push rights, see also: see also: Ciro Santilli's minor projects.

Since you can't escape shitty browser GUIs and live in the command line, the next best thing you can do is to bring Vim bindings to your browser :-)

There is one major annoyance: you can't use ESC to leave the address bar focus, but using Tab as a workaround works: