Installing/upgrading Scala

Because I keep forgetting:

cd /opt
sudo tar xzf ~/install/scala-2.7.1.final.tgz
sudo rm scala
sudo ln -s scala-2.7.1.final scala
cd scala
sudo bin/sbaz install scala-devel-docs

This cryptic message when installing the docs indicates lack of privileges, ie, not running with sudo:

planning to install: scala-devel-docs/2.7.1.final
Installing...
java.io.FileNotFoundException: /opt/scala-2.7.1.final/meta/cache/scala-devel-docs-2.7.1.final.zip.tmp (No such file or directory)