zile
Zile is a lightweight clone of the Emacs text editor.
TLDR
Start a buffer for temporary notes, which won't be saved
$ zile
Open a file
$ zile [path/to/file]
Save a file
$ Ctrl + X, Ctrl + S
Quit
$ Ctrl + X, Ctrl + C
Open a file at a specified line number
$ zile +[line_number] [path/to/file]
Undo changes
$ Ctrl + X, U