sudo port install scala

Sudo will ask for your password. Wait. Done.

Once installed, you may want to know where it was installed. For example, you may need to set the SCALA_HOME environment variable. Just do

port location scala

To update your Scala installation, just do

sudo port upgrade scala

Note that after I upgraded, the location command tracks the old one, even though the new one is active:

$ port location scala
The following versions of scala are currently installed:
scala 2.7.3_0
scala 2.7.4_0 (active)
Error: port location failed: Registry error: Please specify the full version as recorded in the port registry.

So just use ‘@’ to specify the version:

$ port location scala @2.7.4_0
Port scala 2.7.4_0 is installed as an image in:
/opt/local/var/macports/software/scala/2.7.4_0