I am coding Scala and would like an up-to-date 2.8.1 of it to be installed in my Ubuntu 10.10 system, but there is only obsolete 2.7 package available in Ubuntu repositories, so I have to go Slackware-way and use manual installation from tarballs. At the same time there is already scala_2.8.1.dfsg-1_all.deb available for Debian. Can't I just install it in Ubuntu?
You could use the jar installer as follows:
First download the IzPack Installer from the Scala Website, http://www.scala-lang.org/downloads.
Run it with
sudo java -jar installer.jar
and use the default folder /usr/local/scala for the installation
(where for me it was sudo java -jar scala-2.8.1.final-installer.jar).
Then edit /etc/environment so PATH is as follows PATH="... :/usr/local/scala/bin" and add SCALA_HOME=/usr/local/scala
Now logout and login again.
Provided the dependencies are satisfiable, this should generally work.
Since this package probably has only been tested on Debian and not on Ubuntu there is a higher risk that e.g. it doesn't declare all the necessary dependencies or is incompatible with some change in Ubuntu.