I've created a new pull request, which can be found at https://github.com/apache/spark/pull/1929. Since Spark is using Scala 2.10.3 and there is a known issue with Scala 2.10.x not supporting the :cp command (https://issues.scala-lang.org/browse/SI-6502), the Spark shell does not have the ability to add jars to the classpath after it has been started.
The advantage of dynamically adding the jars versus restarting the shell/interpreter (global) is that you can keep your shell's current state (you don't lose your RDDs or anything). The previously-supported Scala 2.9.x implementation wiped the interpreter and replayed all of the commands. This isn't ideal for Spark since some operations can still be quite heavy. Furthermore, if some operations involved loading external data, there is the potential for said data to have changed if you replay the commands. Signed, Chip Senkbeil
