We've come to the end of our intermediate level course. Since this is called an intermediate level course, it implies that our Linux administration skills are only at an in-between level. What is an advanced or expert level then? It's hard to say. Linux is constantly evolving so it may be impossible to sit down one day and say: 'I have arrived - I am a Linux expert'. It may not be a good thing to declare yourself an expert either. US President Harry Truman once said that an expert is a person who refuses to learn new things for fear that he won't be an expert anymore. One of the things that attracted me to Linux in the first place is that it offered an excellent learning experience, so I honestly hope I never become an expert.
Keeping your systems secure
One of the things you'll need to keep track of is security announcements. This is perhaps the most important job of a system administrator. From time to time, exploits are found in software that runs under Linux. Luckily, these programs are fixed fairly quickly and new packages are issued. It will be your job to update packages that provide these fixes and to do them in a timely fashion. The best way to keep track of this area is to sign up to your preferred distribution's security mailing list. That way you won't get caught off guard.
You also need to look at the log files on a regular basis. Use the tools we talked about - tools like grep, sed, awk and perl to automate some of them and to make these tasks more comfortable.
If you're providing services to other users, you'll have to make sure that they're using but not abusing them. This doesn't mean that you should go snooping around in their files - that wouldn't be ethical. Users shouldn't be taking up excessive disk space or have extremely large mail spools. Those users that you have trusted with certain higher privileges through sudo have to use them adequately. In the end, making sure that everybody's doing what they should is your responsibility.
Keeping a system up-to-date
Periodically, you'll have to evaluate the need to move up to newer versions of programs, the Linux kernel or even the whole distribution. If you and management make the decision to update, then you'll have to guide users through the transition. It's a good idea to look at Linux news sites and forums to see what others are doing and what their experiences have been. As you can see, good administration skills go far beyond just keeping the systems running. You may find yourself assuming the role of advocate, spokesman and teacher. If your administration skills are solid, you should have no problem assuming these roles.
Information is always available
One of the advantages of running Linux system is the wealth of freely available information about all aspects of use. The community is to be lauded for its selfless dedication to creating an enormous knowledge base on all things Linux. Linux users are good at sharing their experiences so information related to a problem that you might have can be easily found on the Internet because others may have had the same or similar problem. Mailing lists and forums are there for the asking and if you respect the rules, you should be able to both find information and contribute. In the end, if you're totally stuck, a polite mail to the developer himself/herself might clear up the problem in the end.
What's left for you to do now? Practice, improve, learn. I find it extremely helpful to keep a diary documenting the things that I have done and how I did them. Most of the content of this course comes from that diary. If you find a particular task boring, try to find a more efficient or interesting way of doing it and then write it down and share it with others. Not only will you become more proficient, but you'll free up time for yourself and you can add to your skill set by doing other things with that time. This course has hopefully served as a basic guide to start you off - now itís up to you to continue.