I setup a private IRC server today on an Ubuntu 12.04LTS machine, but ran into some frustrations in the process. Hopefully, this can simplify the process for you.
The process of adding many users to a new Linux system can get tedious, especially if it is involved. So, let's replace the process with a simple shell script.
For this example, public keys are the only allowed login method. Password login is disabled, so the password is not set. The first step is to run set -e to stop the script on any errors. Next assign readable variable names, and check they aren't null. Next the user is created, and as the user the public keys are setup.
Update 2/11/14: I've created https://github.com/eosrei/install-apache-solr an install.sh for Solr 4.6.x on Debian/Ubuntu. I suggest you use it.
There are probably enough posts the Internet covering Apache Solr installation, but here is multi-instance (not-core) Apache Solr 3.6.x with Tomcat6 for Drupal 7 on Ubuntu 12.04 LTS. Perhaps it'll be useful for you. This setup is used on a development server to host search indexes for many development sites.
We recently purchased a new computer for my mother. She wanted nothing to do with Windows, and asked if we could install Linux. An Ubuntu 10.10 install went well, but a few things were missing. Namely, the 10hr+ battery life claimed by the manufacturer. I quickly discovered the LCD brightness was set to 100% and both video cards were enabled.