Vi

Vi (pronounced "vee-eye") is short for VIsual editor, and is a classic but controversial text editor for Unix. Vi's main benefit is that it works with any ordinary terminal: the editor doesn't require a desktop environment, and can be used via telnet or ssh much like NetHack. Beyond this comparison, vi's primary source of relevance to the game is as the origin of the use of [hjkl] for movement (the programmers of vi did not care much about moving the cursor diagonally).

The programmers of Rogue likely adopted the [hjkl] movement system because their keyboards lacked both numeric keypads and separate arrow keys, and added [yubn] for diagonal movement; this yuhjklbn system was in turn adopted for NetHack.

vi is primarily used for editing nethackrc files via the vi-like editor called virus when playing on nethack.alt.org or Hardfought. If you aren't comfortable using a vi-like program to edit text, NAO and Hardfought also offer web-based configuration editors.

Usage

Vi has two different modes: one for giving commands to the editor, and one for editing the text. The editor starts out in the command-mode.

Keys	Command
i	Enter editing mode. (Insert)
a	Enter editing mode. (Append)
Esc	Return from editing mode back to command-mode.
h, j, k and l	Move cursor left, down, up and right
$	Move cursor to the end of line.
^	Move cursor to the beginning of line.
G	Move cursor to the end of the file.
:wEnter	Save changes to file.
:q!Enter	Quit without saving changes.
x	Delete the character under the cursor.
dd	Delete the line under the cursor.
p	Paste deleted text.

You will find vi in many Unix systems, though some GNU/Linux distros (notably Debian and Gentoo) leave it away from of the core system. To learn about vi in general, you could try to start with H2G2's brief description vi, then move to vi@Everything2.com for commands and tutorials. Wikipedia:Vi reveals the history of Vi, while Wiki:ViEditor explains how to pronounce "vi" and links to comparisons with Emacs. There is also an improved version of Vi called Vim.