Advice for everyday Unix systems administration and some clever ways to approach more challenging problems.
Cron is not in charge; you are. All you need to do is tell it what you want done and when you want it done.
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 treasure trove of cheat sheets is yours for the clicking. Visit OverAPI.com for help with nearly any language or tool imaginable.
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 &....
Are you someone who never met a Unix command you didn't like? OK, maybe not. But are there commands you just can't imagine living without? Let's look at some that have made a big difference on my busiest days and those that people I�....
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 ....
Finding a computer infection that is, above all else, designed to remain hidden is not easy work, but neither is it impossible. With some good insights and tools, you might just get a leg up on how the multi-billion dollar spyware industry is attacki....
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 y....
If you haven't worried about rootkits in a while, what are you waiting for? Rootkits remain one of the stealthiest and most worrisome forms of malware compromising systems today.
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 o....
Malware represents one of the greatest threats that organizations face today and IT departments are coming to understand that their AV tools can only do so much to protect them. When malware is discovered on their systems, they want to know what it m....
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.
The quickest way to determine what and how many processors are installed on a Linux system is to turn to the mighty gateway of kernel data -- the /proc pseudo-filesystem. In it, you'll find a file called /proc/cpuinfo that provides a lot of info....
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.
Planning to spend the next six months fighting with troublesome data that you might have to scrub, decode, reformat, store, classify, annotate, visualize, analyze, explain, report and then start all over again? Maybe you should first get some advice ....
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.
Before the chilly winds of a RIF blow in your direction or a pile of your friends take off for greener pastures, you need to be prepared with an easy way to freeze account and preserve what might be of value in the abandoned home directories. In toda....
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.
Complexity isn't all bad. Sometimes it comes with a tremendous boon to security. Are you ready to cozy up to SELinux? Maybe it's time.
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 Ha....
As we find ourselves hurtling toward 2013, it's a good time to think about all the things that we Unix admins would never do ... and how that keeps us out of trouble.
Do you get calls at odd hours because some critical service that you support on your Linux server has stopped working? Here's some late night reading that might help you get the rest you deserve.
Do your hands get sweaty when you have to make changes on your Linux firewall? Iptables isn't as intimidating as it might first seem. After all, it's just a set of tables, and chains, and rules, and the bare essentials of connecting to your....
The ulimit command can keep disaster at bay on your Linux systems, but you need to anticipate where limits will make sense and where they will cause problems.
Samba, the tool that makes it possible to mount Unix directories on Windows systems also works the other way -- allowing you to mount Windows shares on Unix. With an extra package and a few changes in the syntax, you can choose to share files on eith....
Some of my favorite time-savers are here for sharing. Add a comment and tell me about some of your favorite Unix commands.
Before you backup your servers, trouble shoot your major application or read your emails, maybe you should review your grammar. A geek contemplates past and present participles.
Take your Linux servers to the next level by taking advantage of LVM2 -- the best way to manage your disk space!
Basic use of the history command is part of any good introduction to Unix, but there's a lot more to this basic feature than repeating your most recent commands. In fact, some of the more useful applications of command history are typically over....
Have you been putting off setting up an Intranet site because you can't afford the guy who could set it up and manage it for you? Here's an option that you might want to consider.
Are you still living in the world of 755; of user, group and other; and of chmod? If you haven't put Unix ACLs into use, maybe it's time to reconsider how they might compliment your system security process.
Coming soon to a Linux near you? The dramatic improvements in Linux booting are slowly taking over and traditional start scripts are fading fast.
Anyone too comfortable with the idea of run states on Unix systems might not be ready to hear this, but the process of going from a cold piece of hardware to multi-user mode has taken a couple very sharp turns in the last six years or so. Maybe you j....
The sudo command can give you fine-grained security on your Unix servers, but only if you avoid giving too many people the right to run any command as root, especially any command as root without proper logging.
Q: Why don´t you see Penguins in Britain? A: Because they´re afraid of Wales But, if you did, they'd probably be reading this fun new book -- Ubuntu Made Easy: A Project-Based Introduction to Linux, no starch press, 2012 is the most ....
sed is the command of choice for changing this to that between a set of pipes, but there are a lot more tasks you can use it for -- some that it handles much better than the more obvious choices.
Want a script that sends you (up to) monthly sar reports without you having to think about the process? Today's script is way smarter than what I showed you a few weeks ago. It just works with the data it finds.
Some Unix/Linux systems require that a username and password be entered for login. Some can be set up to log you in automatically. For Lubuntu -- a lightweight version of the popular Ubuntu distribution, you can move between these two login options w....
The best way to learn Linux is to use it. A good introductory book will help, but you won't really learn Linux or become confident in your skills unless you park yourself in front of a Linux system and start typing (and popping windows open, cre....
If you don't have sar already installed and running on your Solaris or Linux server, setting it up to monitor performance is so easy, there's no good reason to wait. Follow these simple steps and you'll be monitoring performance on you....
The best trick for understanding performance problems on a Unix system is to understand performance when it ISN'T a problem. If you know what acceptable performance looks like, you'll quickly spot what's out of whack when a system is h....
A key element in the ISO 27001 certification process is to identify and assess risks. While this idea may seem obvious, you may be surprised at how much you can learn about your systems, processes and security threats by pushing them through this ver....
The first step is justifying the first step. Why are you willing to go through an arduous certification process? How it will help your company? The next is getting a whole lot closer to exactly what that means.
A relatively new international standard sets expectations for information security, but is it any better than what you're already doing to protect your systems and your company's intellectual property? Let's examine what it means to be....
If you have need to balance traffic among a set of servers and can't afford a load balancer, you can get fairly effective relief using what is often referred to as "poor man's load balancing" -- an easy trick that you implement on....
Adding swap space to a hurting Linux server is not only easy, but it works. With a few strokes of your hand, you can add swap space and get the system using it. Run another command and see how much difference the change has made.
There are several useful commands for looking at memory use on Linux systems, but if you don't know what the numbers mean, you may think your systems are in bad shape when they're really OK.
Need to move files between Unix and Windows? No problem. There are several different ways of doing just that. One will surely meet your need.
Save yourself some time by taking advantage of Perl's easy ability to manipulate text. When it comes to Perl, if you can describe it, you can do it.
You may be a Unix devotee, but if your organization uses both Windows and Unix systems, you need to understand how password complexity is configured on both platforms.