lush(1) Lisp Universal Shell


lush [@initfile][lushfile...args...]


lush starts the Lisp Universal Shell.

Lush is an object-oriented Lisp interpreter/compiler with features designed to please people who want to prototype large numerical applications. Lush includes an extensive library of vector/matrix/tensor manipulation, a set of graphic functions, a simple GUI toolkit, and interfaces to various libraries such as OpenGL, SDL, the SGI Multimedia library (video/audio grabbing), the Numerical Recipes library, and others. Lush is an ideal frontend script language for programming projects written in C or other languages.


Online help on the standard library is available by typing (helptool) at the Lush prompt. You can leave Lush by typing CTRL-D at the prompt.

On startup, Lush loads various libraries from the sys and lsh directories, as well as a .lushrc file in the user's home directory. It is recommended to add a directory lsh in your home directory and to include the line (addpath "your-home-directory/lsh") to your .lushrc so that your own Lush programs are found in Lush's search path.

It is quite convenient to run Lush from within Emacs, which can be done by creating somewhere in your path a symbolic link named "lisp" to the lush executable. Then, type ESC-X run-lisp in Emacs. It is probably a good idea to add the following line in your .emacs so Emacs switches to Lisp mode when editing a Lush file:

  (setq auto-mode-alist (append (cons "\.lsh$" 'lisp-mode) auto-mode-alist))


In Unix, Lush can be used to write scripts that can be called from a shell prompt (like shell or Perl scripts). A list of command-line arguments are put in the argv variable.

Here is an example: create a file (say "capargs") with the following content (replacing the first line by the path to your lush executable):

  exec lush "$0" "$@"
  (printf "capitalizing the arguments:)
  (each ((arg argv)) (printf "%s %s arg (upcase arg)))

then, make capargs executable: chmod a+x capargs. You can now invoke capargs at the shell prompt:

  % capargs asd gfdf
  capitalizing the arguments:
  capargs CAPARGS
  asd ASD
  gfdf GFDF



The top of the Lush directory structure

Source code of the interpreter

Core libraries (lush sources) without which Lush cannot run. A minimal/customized version of Lush needs only that directory to run.

Various shell scripts and utilities


Library files (lush sources) that are part of the standard distribution. Although they are not required for Lush to run, life would really suck without them.

Library files (lush sources) for special applications or platforms, or programs that have been contributed by users and cannot be assumed to be present/working in all installations of Lush.

Lush libraries that are specific to your site.

Personal Lush initialization file

Personal Lush directory: on-demand built libraries, etc


Lush is the direct descendant of the SN system. SN was first developed as a neural network simulator with a Lisp-like scripting language. The project was started in 1987 by Leon Bottou and Yann LeCun, and rewritten several times since then. SN was used at AT&T for many research projects in machine learning, pattern recognition, and image processing. Its various incarnations were used at AT&T Bell Labs, AT&T Labs, the Salk Institute, the University of Toronto, Universite of Montreal, UC Berkeley, and many other research institutions. The commercial versions of SN were used in several large companies as a prototyping tool: Thomson-CSF, ONERA.


Lush was written by Leon Bottou and Yann LeCun. Contributors include: Patrice Simard, Yoshua Bengio, Jean Bourrelly, Patrick Haffner, Pascal Vincent, Sergey Ioffe, and many others.

This manual page was written by Kevin Rosenberg <[email protected]> for the Debian Project (but may be used by others).