How To Configure Leiningen to Use An HTTP Proxy

I spent a couple of hours banging my head against a wall over this.  Leiningen doesn't respect the HTTP_PROXY environment variable as most Unix programs do.  I finally asked on the Clojure IRC channel and got the answer from manutter: leiningen, of course, uses maven for its dependency management.  Maven, in turn, doesn't respect the environment variable.  Instead you need to configure a specific file in your ~/.m2 directory.

Hope this helps someone.