“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)
The link above will get you the stable release. The Leiningen 2 preview release has some great new features, but not all projects and plugins have been upgraded to work with it yet. Please see the upgrade guide for instructions on migrating to version 2.
On Windows most users can get
the batch file.
If you have 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 commas:
$ lein 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.
See the FAQ for more details.
project.clj file in the project root should look like this:
(defproject myproject "0.5.0-SNAPSHOT" :description "A project for doing things." :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 supports plugins which may contain both new tasks and hooks
that modify behaivour 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 from
explains how to write plugins.
Please report issues on the
GitHub issue tracker
or the mailing list.
Personal email addresses are not appropriate for bug reports. See
readme for the leiningen-core library
doc/PLUGINS.md for more details on how Leiningen’s codebase is
structured. Design discussions also occur in the
#leiningen channel on Freenode.
Patches are preferred as GitHub pull requests, though patches from
git format-patch are also welcome on the mailing list. Please use
topic branches when sending pull requests rather than committing
directly to master in order to minimize unnecessary merge commit
Contributors who have had a single patch accepted may request commit rights on the mailing list or in IRC. Please use your judgment regarding potentially-destabilizing work and branches. Other contributors will usually be glad to review topic branches before merging if you ask on IRC or the mailing list.
Contributors are also welcome to request a free Leiningen sticker by asking on the mailing list and mailing a self-addressed, stamped envelope.
You don’t need to “build” Leiningen per se, but when you’re using a checkout you will need to get its dependencies in place.
For the master branch, use Leiningen 1.x to run
lein install in the
leiningen-core subproject directory. When the dependencies change
you will also have to do
rm .lein-classpath in the project root.
Once you’ve done that, symlink
bin/lein to somewhere on your
$PATH, usually as
lein2 in order to keep it distinct from your
If you want to develop on the 1.x branch, this should be unnecessary.
Source Copyright © 2009-2012 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.