Advice for everyday Unix systems administration and some clever ways to approach more challenging problems.
If you get a secret thrill out of a well crafted Perl one-liner, but only have a few that you can pull out of your mental pocket and use, this book may be just what Santa should be leaving under your tree!
Sometimes what seems like the simplest of questions can have you scrambling for answers. Today's seemingly simple question is "How can a bash script identify its own location?"
Sorting data numerically and alphanumerically isn't generally much of a challenge on Unix systems, but sometimes .5 is smaller than .11.
Last week's post provided some tips and tricks for debugging scripts. This week's provides some even better ones!
All kinds of things can go wrong with your shell scripts, but they don't have to. Let's look a some debugging tips that can help ensure your scripts run the way you intend.
The kill command provides a lot more functionality than just terminating processes. You can use it to send any of more than 60 signals to processes and what happens next depends on the signal, the process and maybe even your settings.
It's easy to find files on Unix systems. You can find them by almost any criteria that you can imagine. The bigger challenge is deciding how to describe what you're looking for and deciding what to do with the files once you find them.
One of the most endearing qualities of Unix devotees is how determined they are to be as efficient as possible. Why type three characters if you can do the same thing with two? And one of the best ways to cut down keystrokes is to turn common command....
Unlike federal shutdowns, Unix shutdowns (and reboots) are generally smooth and easy, don't cost $24B and leave the system in better shape.
Ever need to look into a Unix process to see exactly what it's doing? The ps and top commands only give you a bird's eye view of what's going on. But strace will let you peer into a process' inner workings.
The CISSP is a valuable certification, but it takes a lot more than just your many years of experience to prepare for it. You will likely have to learn about a lot of technology and processes that you’ve never worked with, some of it not especi....
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.
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