The CLISP Common Lisp implementation is a good general-purpose interpreter licensed under the terms of the GNU GPLv2. Though not as popular as SBCL, it sports an intuitive user interface, a byte-code compiler and an easy-to-use debugger.

It also includes various useful extensions to the official ANSI standard, such as foreign function calls and a socket interface. (Note however that using implementation-specific features binds one to the GPL.)


Download one of the packages or pre-built binaries.

Installing on Linux

On Ubuntu/Debian-based systems, you can install CLISP from the repositories with the following command:

apt-get install clisp

On Arch-based systems, use:

pacman -S clisp

On Fedora (>= 18, if you have an old version of Fedora, replace dnf with yum):

dnf install clisp

On Gentoo:

emerge -auvDN dev-lisp/clisp

Note that you will probably need admin privileges to install any software on your computer (e.g. by using sudo)