"Leiningen!" he shouted. "You're insane! They're not creatures you can fight—they're an elemental—an 'act of God!' Ten miles long, two miles wide—ants, nothing but ants! And every single one of them a fiend from hell..."
- from Leiningen Versus the Ants by Carl Stephenson
Leiningen is for automating Clojure projects without setting your hair on fire.
If your preferred package manager has a relatively recent version of Leiningen, try that first. Otherwise you can install by hand:
Leiningen bootstraps itself using the
lein shell script;
there is no separate install script. It installs its dependencies
upon the first run on unix, so the first run will take longer.
- Download the script.
- Place it on your
$PATH. (I like to use
- Set it to be executable. (
chmod 755 ~/bin/lein)
There is still a lot of extant material on the Web concerning the older Leiningen 1.x version, which is still available if you need to work on older projects that aren't compatible with 2.x yet. The upgrade guide has instructions on migrating to version 2.
On Windows most users can get
the batch file.
If you have PowerShell, wget.exe or curl.exe already installed and in PATH, you
can just run
lein self-install, otherwise get the standalone jar from the
If you have Cygwin you should be able to use
the shell script above rather than the batch file.
The tutorial has a detailed walk-through of the steps involved in creating a new project, but here are the commonly-used tasks:
$ lein new [TEMPLATE] NAME # generate a new project skeleton $ lein test [TESTS] # run the tests in the TESTS namespaces, or all tests $ lein repl # launch an interactive REPL session $ lein run -m my.namespace # run the -main function of a namespace $ lein uberjar # package the project and dependencies as standalone jar
lein help to see a complete list.
lein help $TASK shows the
usage for a specific task.
You can also chain tasks together in a single command by using the
do task with comma-separated tasks:
$ lein do clean, test foo.test-core, jar
Most tasks need to be run from somewhere inside a project directory to
work, but some (
run from anywhere.
project.clj file in the project root should look like this:
(defproject myproject "0.5.0-SNAPSHOT" :description "A project for doing things." :license "Eclipse Public License 1.0" :url "http://github.com/technomancy/myproject" :dependencies [[org.clojure/clojure "1.4.0"]] :plugins [[lein-ring "0.4.5"]])
lein new task generates a project skeleton with an appropriate
starting point from which you can work. See the
file (also available via
lein help sample) for a detailed listing of
project.clj file can be customized further with the use of
Leiningen documentation is organized as a number of guides:
- Polyglot (e.g. Clojure/Java) projects
- Leiningen Profiles
- Deployment & Distribution of Libraries
- Sample project.clj
- Writing Plugins
Leiningen supports plugins which may contain both new tasks and hooks
that modify behaviour of existing tasks. See
the plugins wiki page
for a full list. If a plugin is needed for successful test or build
runs, (such as
lein-tar) then it should be added to
project.clj, but if it's for your own convenience (such as
swank-clojure) then it should be added to the
:plugins list in the
:user profile in
~/.lein/profiles.clj. See the
for details on how to add to your
:user profile. The
explains how to write plugins.
Source Copyright © 2009-2013 Phil Hagelberg, Alex Osborne, Dan Larkin, and contributors. Distributed under the Eclipse Public License, the same as Clojure uses. See the file COPYING.
Thanks to Stuart Halloway for Lancet and Tim Dysinger for convincing me that good builds are important.
Images Copyright © 2010 Phil Hagelberg. Distributed under the Creative Commons Attribution + ShareAlike License. Full-size version available.