<!DOCTYPE html> <html lang="en"> <head> <meta charset="utf-8"> <title>A summary of Emacs' bundled shell and terminal modes — Luke Shumaker</title> <link rel="stylesheet" href="assets/style.css"> <link rel="alternate" type="application/atom+xml" href="./index.atom" name="web log entries"/> </head> <body> <header><a href="/">Luke Shumaker</a> » <a href=/blog>blog</a> » emacs-shells</header> <article> <h1 id="a-summary-of-emacs-bundled-shell-and-terminal-modes">A summary of Emacs' bundled shell and terminal modes</h1> <p>This is based on a post on <a href="http://www.reddit.com/r/emacs/comments/1bzl8b/how_can_i_get_a_dumbersimpler_shell_in_emacs/c9blzyb">reddit</a>, published on 2013-04-09.</p> <p>Emacs comes bundled with a few different shell and terminal modes. It can be hard to keep them straight. What's the difference between <code>M-x term</code> and <code>M-x ansi-term</code>?</p> <p>Here's a good breakdown of the different bundled shells and terminals for Emacs, from dumbest to most Emacs-y.</p> <h2 id="term-mode">term-mode</h2> <p>Your VT100-esque terminal emulator; it does what most terminal programs do. Ncurses-things work OK, but dumping large amounts of text can be slow. By default it asks you which shell to run, defaulting to the environmental variable <code>$SHELL</code> (<code>/bin/bash</code> for me). There are two modes of operation:</p> <ul> <li>char mode: Keys are sent immediately to the shell (including keys that are normally Emacs keystrokes), with the following exceptions:</li> <li><code>(term-escape-char) (term-escape-char)</code> sends <code>(term-escape-char)</code> to the shell (see above for what the default value is).</li> <li><code>(term-escape-char) <anything-else></code> is like doing equates to <code>C-x <anything-else></code> in normal Emacs.</li> <li><code>(term-escape-char) C-j</code> switches to line mode.</li> <li>line mode: Editing is done like in a normal Emacs buffer, <code><enter></code> sends the current line to the shell. This is useful for working with a program's output.</li> <li><code>C-c C-k</code> switches to char mode.</li> </ul> <p>This mode is activated with</p> <pre><code>; Creates or switches to an existing "*terminal*" buffer. ; The default 'term-escape-char' is "C-c" M-x term</code></pre> <p>or</p> <pre><code>; Creates a new "*ansi-term*" or "*ansi-term*<n>" buffer. ; The default 'term-escape-char' is "C-c" and "C-x" M-x ansi-term</code></pre> <h2 id="shell-mode">shell-mode</h2> <p>The name is a misnomer; shell-mode is a terminal emulator, not a shell; it's called that because it is used for running a shell (bash, zsh, …). The idea of this mode is to use an external shell, but make it Emacs-y. History is not handled by the shell, but by Emacs; <code>M-p</code> and <code>M-n</code> access the history, while arrows/<code>C-p</code>/<code>C-n</code> move the point (which is is consistent with other Emacs REPL-type interfaces). It ignores VT100-type terminal colors, and colorizes things itself (it inspects words to see if they are directories, in the case of <code>ls</code>). This has the benefit that it does syntax highlighting on the currently being typed command. Ncurses programs will of course not work. This mode is activated with:</p> <pre><code>M-x shell</code></pre> <h2 id="eshell-mode">eshell-mode</h2> <p>This is a shell+terminal, entirely written in Emacs lisp. (Interestingly, it doesn't set <code>$SHELL</code>, so that will be whatever it was when you launched Emacs). This won't even be running zsh or bash, it will be running "esh", part of Emacs.</p> </article> <footer> <p>The content of this page is Copyright © 2013 <a href="mailto:lukeshu@sbcglobal.net">Luke Shumaker</a>.</p> <p>This page is licensed under the <a href="https://creativecommons.org/licenses/by-sa/3.0/">CC BY-SA-3.0</a> license.</p> </footer> </body> </html>