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Timers provide finer-grained control of events than cronjobs. I am in the process of converting my cron jobs to systemd timers. I have used timers for a few years, but usually, I learned just enough to perform the task I was working on. While doing research for this systemd series, I learned that systemd timers have some very interesting capabilities. Like cron jobs, systemd timers can trigger eve

In addition, htop provides system overview information at the top and a command bar at the bottom to trigger commands using the function keys, and you can customize it by pressing F2 to enter the setup screen. In setup, you can change its colors, add or remove metrics, or change display options for the overview bar. While you can configure recent versions of top to achieve similar results, htop pr

Try some of these open source tools. Get more done. Many of us, admittedly, only use computers because they're fun. But some people use computers to get stuff done, and their theory is computers are supposed to make things faster, better, and more organized. In practice, though, computers don't necessarily improve our lives without a little manual reconfiguration to match our individual work style

Each of these Raspberry Pi projects is designed to make your life easier and more productive. There's nothing like the thrill of experiencing the result of your Raspberry Pi creation. After hours of coding, testing, and building with your bare hands, your project starts to finally take shape and you can’t help but yell "woohoo!." I’m fascinated by the possibilities of what the Raspberry Pi can bri

There are several ways to get started with Python 3 on macOS, but one way is better than the others. I've been dipping my toe back into Python development as I get ready to head to PyCon US. (If you're headed there as well and want to share your Python story, let me know!) When I installed a module to tinker around with, I got a reminder that I needed to install Python 3 soon. $ pip install todois

We all use the Internet Protocol (IP) daily, whether we're aware of it or not. For instance, any time you type a website name or a search term into your web browser, it looks up the IP address of that URL (or of a search engine) and then loads the website. Let's divide IP addresses into two categories: private and public. Private IP addresses are the ones your WiFi box (and company intranet) provi

Get the details on what's inside your computer from the command line. There are many reasons you might need to find out details about your computer hardware. For example, if you need help fixing something and post a plea in an online forum, people will immediately ask you for specifics about your computer. Or, if you want to upgrade your computer, you'll need to know what you have and what you can

Yes, testing in production is risky, but we should still do it, and not in rare or exceptional cases. If you last updated your IT security standards five or more years ago, chances are they don't line up well with the realities of today's DevOps and site reliability engineering (SRE) practices. One particularly sticky topic is testing in production—and, thus, testing with production data—because D

Discover what's behind the standards for operating system compatibility from a pioneer of computer freedom. What is POSIX, and why does it matter? It's a term you've likely seen in technical writing, but it often gets lost in a sea of techno-initialisms and jargon-that-ends-in-X. I emailed Dr. Richard Stallman (better known in hacker circles as RMS) to find out more about the term's origin and the

Any good network-level security tool will also give you information on the types of attacks the tool is blocking and how it recognizes likely attacks. This information is available in the marketing materials online as well as the tool’s console and reports if you have access to those. Each of your development teams or squads should have at least one subject matter expert who takes the time to read

In this three-part series, I'll explain how to set up a simple, useful NAS (network attached storage) system. I use this kind of setup to store my files on a central system, creating incremental backups automatically every night. To mount the disk on devices that are located in the same network, NFS is installed. To access files offline and share them with friends, I use Nextcloud. This article wi

A reference list of Linux utilities and commands makes managing servers and networks easier. If you're a sysadmin, your daily tasks include managing servers and the data center's network. The following Linux utilities and commands—from basic to advanced—will help make network management easier. In several of these commands, you'll see <fqdn>, which stands for "fully qualified domain name." When yo

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Writing clean code is just one of many factors you should care about when creating a pull request. Large pull requests cause a big overhead during the code review and can facilitate bugs in the codebase. That's why you need to care about the pull request itself. It should be short, have a clear title and description, and do only one thing. Why should you care? A good pull request will be reviewed

Do you ever get the funny feeling that your computer isn't quite as fast as it should be? I used to feel that way, and then I found GNU Parallel. GNU Parallel is a shell utility for executing jobs in parallel. It can parse multiple inputs, thereby running your script or command against sets of data at the same time. You can use all your CPU at last! If you've ever used xargs, you already know how

Keep your Kubernetes containers running smoothly with these self-healing probes. One of the main advantages of using Kubernetes is its ability to maintain containers running in a cluster: Simply create a pod resource, let Kubernetes choose a worker node for it, and it will run the pod’s containers on that node. But what if a container or a pod fails? As soon as a pod is scheduled to a node, the ku

If you (or someone you know) ever forget your Windows password, you'll be glad to know about chntpw, a neat Linux utility that you can use to reset a Windows password. For this how-to, I created a Windows virtual machine and set the password to pass123 on my user account, Archit-PC. I also created a Live USB with Fedora 27 using the Fedora Media Writer application.

Christine Peterson finally publishes her account of that fateful day, 20 years ago. In a few days, on February 3, the 20th anniversary of the introduction of the term "open source software" is upon us. As open source software grows in popularity and powers some of the most robust and important innovations of our time, we reflect on its rise to prominence. I am the originator of the term "open sour

My signature hobby project these days is a computerized instrument cluster for my car, which happens to be a DeLorean. But, whenever I show it to someone, I usually have to give them a while to marvel at the car before they even notice that there's a computer screen in the dashboard. There's a similar problem when I start describing the software; programmers immediately get hung up on "Why Perl???

The oldest joke in open source software is the statement that "the code is self-documenting." Experience shows that reading the source is akin to listening to the weather forecast: sensible people still go outside and check the sky. What follows are some tips on how to inspect and observe Linux systems at boot by leveraging knowledge of familiar debugging tools. Analyzing the boot processes of sys

Look deeply into your Linux code with these Berkeley Packet Filter (BPF) Compiler Collection (bcc) tools. A new technology has arrived in Linux that can provide sysadmins and developers with a large number of new tools and dashboards for performance analysis and troubleshooting. It's called the enhanced Berkeley Packet Filter (eBPF, or just BPF), although these enhancements weren't developed in Be

Larry Wall released Perl 1.0 to the comp.sources.misc Usenet newsgroup on December 18, 1987. In the nearly 30 years since then, both the language and the community of enthusiasts that sprung up around it have grown and thrived—and they continue to do so, despite suggestions to the contrary! Wall's fundamental assertion—there is more than one way to do it—continues to resonate with developers. Perl

Containers provide an easy way to package applications and deliver them seamlessly from development to test to production. This helps ensure consistency across a variety of environments, including physical servers, virtual machines (VMs), or private or public clouds. These benefits are leading organizations to rapidly adopt containers in order to easily develop and manage the applications that add

One day at work, we were discussing the Go programming language in our work chatroom. At one point, I commented on a co-worker's slide, saying something along the lines of: "I think that's like stage three in the seven stages of becoming a Go programmer." Naturally, my co-workers wanted to know the rest of the stages, so I briefly outlined them. Here, expanded with more context, are the seven stag

There is little worse as a developer than trying to figure out why an application is not working if you don't know what is going on inside it. Sometimes you can't even tell whether the system is working as designed at all. When applications are running in production, they become black boxes that need to be traced and monitored. One of the simplest, yet most important ways to do so is by logging. L

It's never easy to admit when you do things wrong, but making errors is part of any learning process, from learning to walk to learning a new programming language, such as Python. Here's a list of three things I got wrong when I was learning Python, presented so that newer Python programmers can avoid making the same mistakes. These are errors that either I got away with for a long time or that th

Vim can be a challenge to learn. But for many first-time users, just exiting the program can be a problem. Last month, the Stack Overflow blog published an article on "helping one million developers exit Vim," a testament to the then-recent milestone of a million views on a popular question on the developer help site: how to exit the Vim editor? Based on the traffic, Stack Overflow says that durin