See http://code.google.com/p/simple-build-tool/wiki/Setup for setup instructions for the stable version of sbt.

To build from source, get the latest stable version of sbt (above) and get the code:

$ git clone git://github.com/harrah/xsbt.git
$ cd xsbt

The latest tag for 0.9.x is 0.9.0:

$ git checkout v0.9.0

Or, get the development branch for 0.9.x:

$ git checkout 0.9

To build:

$ sbt update "project Launcher" proguard "project Simple Build Tool" "publish-local"

Copy your stable ~/bin/sbt script to ~/bin/xsbt and change it to use the launcher at:

<xsbt>/target/sbt-launch-0.9.0-SNAPSHOT.jar