Do-It-Yourself projects to get to know the inner workings of a Linux system.
If you're a "learn by doing" kind of person, here are some small projects that will help you learn how Linux works underneath the drag and drop interfaces of Gnome, KDE and window managers.

If you're interested in (server) system administration or want to find out how to troubleshoot a Linux desktop by simply editing a configuration file, these projects will help you with your first steps.

All projects use Debian and/or Ubuntu, and the focus is on command line and shell scripts. The emphasis on command line work and editing plain text configuration files will help you learn what the file system looks like, where applications and daemons get their configuration from (and how to change it without depending on GUI tools), how scripting can help to automate system administration tasks, and how to shortcut general troubleshooting issues.