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Don't let an ISO 27001 audit ruin your week. Chin up and follow some simple rules to chase away the pain and the worry.

A number of people have asked recently what it takes to be a Unix systems administrator, what “core competencies” are required, and what are the best and worst aspects of the job. Here are some answers that might work once we get beyond “it depends”.

While pipes are one of the things that make Unix such a powerful and versatile operating system, they don't always make sense. Many people still fall into the "useless use of a pipe" habit while still others use pipes in situations in which pipes simply don't function at all. Knowing when to pipe and when not to pipe remains a sign of Unix mastery. If you want to look Unix savvy, use pipes only when they provide a critical service and never when they're superfluous or downright wrong.

You could have a rootkit infection right now and be totally unaware. One of the key goals of a rootkit is, after all, to go undetected. If the rootkit is hiding files, processes, logins, etc., how would you know? If you can't see it, how would you remove it?

If you've ever wondered how Unix systems identify files, you might be surprised to learn that file names really aren't an important factor. Unix systems reach into files looking for special codes called "magic numbers" to figure out what your files really are. They also examine other file content to pick out additional details.

Don't throw up your hands if your boss won't buy you Tripwire and a modern debugger. There are a lot of things that your Unix system -- right out of the box -- can tell you about files and processes.

Hard links are not called "hard" because they're difficult. They're just ... mildly elusive. Read on and find out why one long-time Unix admin thinks hard links are the penguin's meow.

If you're only comfortable with CIDR when the / is followed by a multiple of 8, a quick refresher on how the numbers work might be just what you need for a balmy January afternoon.

If you love Unix but fear programming or have a kid who you'd like to convince that programming is fun, here's a book you really should consider.

Hardening tips for Unix systems have been issued for decades, but when's the last time you stopped to review how your servers stack up against the latest advice from the sages? Let's check out some of the recommendations provided for Red Hat Enterprise Linux 5 and see what you might gain or lose by implementing them.

Effective troubleshooting requires that you know how to break a problem into pieces, track down evidence, and that you understand your systems and applications -- as well as the tools at your disposal -- well enough to analyze problems when they rear their ugly heads.