Installing Clojure on Mac OS X

The following instructions are for installing Clojure on Mac OS X 10.6 (Snow Leopard), although they should work for any *nix based system.


Java 1.5 or greater is require for running Clojure. This already comes pre-installed on OS X. Run the following command from the Terminal (in /Applications/Utilities) to ensure that this dependency is met.

$ java -version
java version "1.6.0_17"
Java(TM) SE Runtime Environment (build 1.6.0_17-b04-248-10M3025)
Java HotSpot(TM) 64-Bit Server VM (build 14.3-b01-101, mixed mode)

If you don't see something similar to the previous you will need to install java. Also since we will be compiling Clojure from source git is required to check out the source code and Ant is required to build Clojure. Run the following to see if git is installed.

$ git --version
git version 1.6.6

If you see something similar, git is installed and you can move on. If you don't see something similar to the previous then you will need to install git. Follow these instructions.

And now make sure ant is installed. Its included with OS X, so it you won't have to install anything.

$ ant -version
Apache Ant version 1.7.1 compiled on September 22 2009

Set the PATH

The PATH variable tells the Terminal where to find the programs that are about to be installed.

If you are using Textmate you can use the following command to open the file.

$ mate ~/.profile

Go ahead and open the ~/.profile and make sure that the PATH variable is set and includes /usr/local/bin and /usr/local/sbin. You should have a line in the file that looks similar to the following, if not add it to the end of the file.

export PATH="/usr/local/bin:/usr/local/sbin:$PATH"

After saving the file, return to the Terminal and run the following command.

$ source ~/.profile

Download and Install

Since we will be installing from source we need a place that we can download the source to and compile. Once the installation is complete the directory can then be deleted.

Make the folder:

$ mkdir ~/src && cd ~/src

Download Clojure:

$ git clone git://
$ cd clojure
$ git checkout 1.1.0
$ ant

Test the build:

$ java -cp clojure-1.1.0.jar clojure.main
Clojure 1.1.0
user=> (+ 1 1)
user=> (System/exit 0)

If Clojure told you that 1 + 1 is 2 then it looks like things are working. Now we can install. This is not a typical install, all we do is just move the .jar file.

$ sudo mkdir /usr/local/lib/clojure
$ sudo cp clojure-1.1.0.jar /usr/local/lib/clojure/clojure.jar

Install rlwrap

rlwrap will make interacting with the Clojure REPL much more friendly. It is not necessary but I recommend it. With rlwrap you will have tab completion, parenthesis matching, and much more. The easiest way to install rlwrap is with MacPorts. Go ahead and install MacPorts if you don't have it installed. (The brave will install this from source.)

$ sudo port install rlwrap

Now you should be able to run the following command.

$ rlwrap --version
rlwrap 0.30

Create the clj Script

This is the script that will be called from the command line when you type clj. In your editor of choice open /usr/local/bin/clj. If you are using Textmate you can use the following command.

$ mate /usr/local/bin/clj

Copy the following text into the file:

# Parts of this file come from:


while [ $# -gt 0 ]
    case "$1" in
    shift ; shift
-e) tmpfile="/tmp/`basename $0`.$$.tmp"
    echo "$2" > "$tmpfile"
    shift ; shift
    set "$tmpfile" "$@"
    break # forces any -cp to be before any -e
*)  break

if [ $# -eq 0 ]
  exec rlwrap --remember -c -b $BREAK_CHARS \
          java -cp $CLASSPATH clojure.main
  exec java -cp $CLASSPATH clojure.main $1 -- "$@"

Make the script executable:

$ sudo chmod +x /usr/local/bin/clj

Now you should be able to run Clojure from the command line.

$ clj

You are now in command of a Clojure REPL. The installation is complete. Try a few commands in the REPL:

user=> (+ 3 5)
user=> (def A [[0 1 2] [3 4 5] [6 7 8]])
user=> (let [[x y z] (first A)]
            (println (+ x y z)))
user=> (println "Hello, World!")
Hello, World!

A file can also be passed to clj to run as a script.

$ clj clojure_script.clj

Installing clojure-contrib

Clojure Contrib contains useful libraries for Clojure. Chances are that they will be used in almost all projects in Clojure. The install is similar to Clojure. Go ahead an check out the source and install with the following commands.

$ cd ~/src
$ git clone git://
$ cd clojure-contrib/
$ git checkout 1.1.0
$ ant -Dclojure.jar=/usr/local/lib/clojure/clojure.jar
$ sudo cp clojure-contrib.jar /usr/local/lib/clojure/clojure-contrib.jar

From the REPL you should be able use the clojure-contrib libraries (clojure-contrib will be on the classpath since it was installed into /usr/local/lib/clojure/).

$ clj
user=> (use 'clojure.contrib.combinatorics)
user=> (permutations [1 2])
((1 2) (2 1))

Clean up

Now you can go ahead an remove the directory that we created at the start to hold the source code and compile it.

$ rm -rf ~/src