Advice for everyday Unix systems administration and some clever ways to approach more challenging problems.
Oh, Danny Boy, the pipes, the pipes are calling. But if you want to call them back, you need to give them names.
If you work in cyber security or incident response, you MUST read this book. It is the best book ever for preparing yourself and your staff for handling inevitable network intrusions.
No matter how much disk space you add to a system, sooner or later you're going to run short. But watching disk space get slowly used up is a lot like watching grass grow. How do you avoid a disk space crisis and avoid being lulled into a data s....
The only thing wrong with sed is that most of us barely grasp how powerful it is. We use it in pipes to change "this" to "that", but we rarely consider it for the big editing jobs where it could save us considerable time and effor....
Moving files between Linux (and other) servers is a lot smarter and more versatile when you discover lftp.
The things that make you love a job or drive you to thinking about moving on may have less to do with how much you earn than whether you look forward to Monday morning.
Sitting in a chair for 40 or more hours a week might seem like the makings of a good life if it's combined with an impressive salary, but if you value your health and/or your career, you might rethink your priorities. This invaluable book could ....
You need to understanding routing tables if you're going to do any kind of network troubleshooting. Let's take a look at what Linux commands can tell you about how your system is making connections.
Friday, July 26th,2013 is Sysadmin Day or "Systems Administrator Appreciation Day" -- a good reason to celebrate those individuals who devote themselves to keeping our servers available, usable and secure, but how do you go about thanking t....
Firewall logs. There's never enough time to review them, but you can't ignore them. Here's one way to look for malicious connections without spending a lot of time at it.
CSV (comma-separated values) files represent a common standard for transmitting data between applications. Like the more generic "flat files", each line in a CSV file represents a record. Exporting or importing data from and to applications....
The grep command has a lot more options and "flavors" than the casual command line pioneer might expect, but there are some options and limitations that you should know about when you're working with big data files.
Big data may be a tech buzzword of the moment, but Unix admins who need to hunt through logs to figure out what's going with their systems have been grappling with huge data sets for decades. Here are tips on command-line tools and techniques th....
Wise men say that you should never choose the easy path but, instead, live life fully. But when it comes to moving around the Unix file system, easy is good. And bash's builtin shopt command can make maneuvering even the most complicated file sy....
The history feature in Unix shells can save you a lot of time when typing long, fairly repetitious commands, but don't count on it to accurately represent history.
If someone told you that, on average, an advanced attacker was on a system for 243 days before he was detected, would you fall off your seat? If so, then, fall off your seat.
Knowing how and when to use the escape character can make your day, but commands get a little hairy when you first have to escape your escape.
You can make your life a little easier and more productive by adding some Unix power to your Windows system.
BSD -- the Berkeley Software Distribution flavor of Unix -- is alive and well and thriving on a remarkably secure system near you. And the second edition of Absolute OpenBSD (Michael W. Lucas, 2013, no starch press) is ready to teach you all about it....
Whether you're setting up accounts for existing users on a new server or providing accounts for a crop of new staff members on your primary server, it's nice to be able to do the job quickly and accurately. The newusers command in Linux is ....
Bash has quietly made scripting on Unix systems a lot easier with its own regular expressions. If you're still leaning on grep and sed commands to get your scripts to do what you need from them, maybe it's time to look into what bash can do....
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....
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