Vim

Vim: Highly configurable text editor

Vim is a configurable application designed for efficient text editing, containing almost all the commands from the UNIX program and a wide collection of new ones.

Vim is a text editor, not a word processor. The difference is that the main usage of a word processor is for text layouts and an editor is used just for entering text. Other actions such as typesetting or laying out the document are considered secondary.

Originally Vim was short for Vi Imitation, but now stands for Vi Improved as a consequence of multiple improvements and modifications.