The /proc/sys directory in the /proc virtual filesytem contains a lot of useful and interesting files and directories. Many kernel settings can be manipulated by writing to files in the proc filesystem. A lot of important information can be retrieved from these files. This is especially useful when you are troubleshooting or fine tuning your linux system.
Following is a description of the most important files.

Especially the files in /proc/sys/vm are very interesting and useful.

This is the 3rd part of a series of articles aimed at teaching the knowledge needed for passing the LPI level 1 exam 1

I've put up a certification practice quiz containing questions similar to those on the certification exam. Take a challenge to test your knowledge level, just for fun or to practice your skills.

I've also put up some questions about the proc directories for people who need to learn these for the exam. I'll add more questions to all practice quizzes in the future.

Practice exam questions on this site!

I've put up a quiz on the site which has 25 random chosen questions to test your level of knowledge. They are chosen random from a pool of questions. The difficulty level and material covered is that of the LPIC 101 exam. If there's demand I'll put up more questions and other exam levels.

Register for free and try your skill level:
(don't worry if you don't have enough time to finish, the test will resume where you left of when you come back.)
LPIC level 1 exam practice

(Also nice to do if you just like to know if you could make it)

Level 1 second exam (lpic 102):
LPIC level 2 exam practice

15 random practice questions about proc available: (more in the future)

proc practice test (hard)

The LPI certification is a valuable certification for Linux system administrators. LPI has partnered with Novell and now the certification has become even more valuable as it's also a Novell certification by now which means you get 2 certifications at once. The LPIC 1 certification is also the base for the ubuntu certified professional certification. So if you like to become a linux all-round certified administrator. This is probably one of the best (and cheapest) choices.

This is the first article in a series of tutorials, which will try to help you prepare for the LPI certification exam.

In a previous article I discussed several ways to reset/recover/circumvent root password. While the article was written to assist people who have lost or forgotten a root password it was also a statement about security. As I was reading up on the subject I noticed there are some things I didn't know about, as my knowledge of the subject has aged a bit.

Security

I remember when I first started administrating Linux systems, I had to use the vi text editor to edit configuration files. My first encounters with vi were not of the pleasant kind. I hated vi, to me it felt completely counter intuitive with its command and editing mode. Which it apparently inherited from the days where terminals had few keys and didn't sport all the typewriter functions we have today.

Often I get ideas when working on a PC, ideas for things that would be nice to have on my system. Most of the time I sooner or later discover someone else had the same idea and build the thing I was thinking of only better.

Free

This is one of the most impressive things about Linux, and one of the things I most enjoy. I dream up something I would like to see and someone else has already built it and is giving it away for free.

Limited by fear

As some people commented on my previous post they don't think you need a virus scanner in Linux, I have some examples.

These things are found by ClamAV:

There is a group of hackers defacing sites, they specialize in Joomla websites. If you run a joomla website for a while, and you don't upgrade it when security updates are published. You have about a 99% change of it being hacked (don't know any real numbers, but I do know people who have experienced this several times).

The other day a friend came to me with a problem, he had been surfing the internet for information about the conficker worm virus. As he misspelled the name as configer virus, he didn't find a lot of real information on the virus. What he did find, were a lot of links, to sites which were indicated by google as harmful to your computer. You know the kind. Where google says near the link:

This site can harm your computer.

Curiosity kills

Thanks to Mike Dailey a very interesting discussion has been sparked on Linux and open source in the enterprise. For anybody wanting to follow the entire discussion here's how it goes.

It started here:

http://www.handlewithlinux.com/10-things-to-tell-your-boss-why-migrate-t...

Mike Dailey responded on his blog with this article:

http://daileymuse.com/2009/03/think-before-you-speak-migrating-the-enter...

While I was working on my response:

http://www.handlewithlinux.com/migrating-the-enterprise-to-linux-10-thin...

A while ago somebody asked me what he could tell his boss to convince him to migrate to Linux, so I made him a small list.

1. Cost

Bosses know calculators, so this is the number one thing to tell your boss why you should migrate to Linux. The total cost of ownership(TCO) of linux is lower than windows. While linux administrators are a little more expensive, they are a lot more efficient so this gives a benefit. The licensing costs are lower, you don't have to migrate to a new OS every few years, you can use the same hardware twice as long.

2. Security

Best racing game ever runs on linux!

Disclaimer: I'm not a racing game fan, in general I don't like racing games at all. So if I say something is the best racing game ever, it's not based on the usual things most racing fans would think make up the best racing game.

mindless gaming

Last night I was looking for a linux game, to do some mindless gaming on the and of a tiring day.