Linux tip: Use systemctl --failed to quickly identify which services failed to start after boot. Much faster than scrolling through journal logs when troubleshooting system issues. #Linux #SystemAdministration #SysAdmin
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Monospace Mentor
@monospace@floss.social
mastodon 4.7.3I'm Jochen Lillich, a greybeard geek and IT operations black belt. #DevOps trainer and mentor. German living in Ireland. Likes #Linux, #Ruby and #MechanicalKeyboards. He/him.
704 Followers
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50 Posts
Joined November 02, 2023
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Tip for Linux shell beginners: Execute a second command only if the first one failed.
`command_1 || command 2`
Background: This compound command uses the result code returned by `command_1` with the "shortcircuit" behaviour of the "logical OR" `||` operator.
One of the features for which I love Ruby is that it has syntax features that let me express clearly what the intention of my code is.
- `unless` instead of `if not`
- `until` instead of `while not`
- `loop do` instead of `while true`
🚨LIVE NOW!🚨 Cozy DevOps chat | Linux, DevOps, SRE - Let's talk about it!
Thursday stream in Just Chatting
If you're looking for a more modern alternative to the `du` command that shows you what's taking up your disk space, try `dust`. It returns a graphical overview with percentages, and uses colours to highlight the largest subdirectories.
"Using positional arguments requires less code today, but you pay for this decrease in volume of code with an increase in the risk that changes will cascade into dependents later." (Sandi Metz)
"The key to managing dependencies is to control their direction. The road to maintenance nirvana is paved with classes that depend on things that change less often than they do." (Sandi Metz)
The concept of Test-Driven Development isn’t particularly new any more. But even after quite a few years of accompanying my code with tests, TDD is still far from being second nature to me. A talk from RubyHACK 2018 motivated me to get better at it.
I love the atomic Fedora distributions for their ability to rebase customizations onto a new OS release. Here’s another great benefit: being able to easily pinpoint the release when a regression crept in.
https://enblog.eischmann.cz/2024/02/15/bisecting-regressions-in-fedora-silverblue/
Are you just starting your engineering career? And you feel like you don’t belong? Be kind to yourself. It’s probably not Impostor Syndrome.
https://monospacementor.com/2024/05/its-not-impostor-syndrome/
"How many times have you seen a comment that is out of date? Because comments are not executable, they are merely a form of decaying documentation. If a bit of code inside a method needs a comment, extract that bit into a separate method." (Sandi Metz)
Version-control every configuration change. Use git even for single files. When something breaks, you can see exactly what changed and when. Your future self will be grateful. #Linux #SystemAdministration #SysAdmin #Coding
Almost every Linux CLI tool that requires you to edit a file will consult the `EDITOR` environment variable to spawn the editor you prefer. If you want to use `nano` instead of `vim`, set it as your default editor like this:
`export EDITOR=nano`
Replying to
@gnomon@mastodon.social Those are all good practices. I need to make myself a ready-to-use script template.
All I'd add is "Know when to switch to a proper programming language." There are too many bash monstrosities in the world already.
Database queries in loops are performance killers. Load all needed data in one query, then process it in memory. One query fetching 1000 records beats 100 queries fetching ten records each by far. #SoftwareEngineering
find is the razor blade of shell tools. You'll make the finest, easiest cuts eventually. But the way to get there is a series of painful nicks.
#sysadmin
Linux tip: Use “journalctl -f -u servicename” for real-time service logs. The “-u” targets specific service units, “-f” follows live output. Add “-p err” for errors only.
🔗 Learn more in my course: https://monospacementor.com/courses/linsys-1/
⭐️ Interesting project: https://github.com/clouedoc/hzfind
A TUI to find the best Hetzner dedicated server auction deals, with PassMark CPU benchmarks built-in
Replying to
@agreeable_landfall@mastodon.social @SteveBellovin@infosec.exchange @aka_pugs@mastodon.social 3C509 and NE2000, the legends of the early Ethernet era.
Replying to
@remi@ruby.social I can imagine all the AI mandates making people more aloof. But I suspect that these days, long-existing carelessness just stands out more.
Monitoring SSL certificates has never been hard.
New System Administration post in The Server Room: "Dual-boot installing error from Bootable drive -- MX linux" https://community.monospacementor.com/t/393
If you'd like to benefit yourself from our community's valuable DevOps/SRE knowledge, consider becoming a TSR member: https://monospacementor.com/devops-learning-community/
New Basic Linux System Administration post in The Server Room: "Cohort conclusion" https://community.monospacementor.com/t/391
If you'd like to benefit yourself from our community's valuable DevOps/SRE knowledge, consider becoming a TSR member: https://monospacementor.com/devops-learning-community/
What logs to check when something's wrong. Which services to restart and when to just reboot. Which "obvious" fix will make things worse.
That's what you pick up in your first year on the job. It's also what my Linux course covers. (1/2)
You can SSH into a server, edit a config file, restart a service. That gets you pretty far. Until something breaks and the gaps start to show.
My course, Basic Linux System Administration, fills in those gaps.
Join TSR at 50% off — your discounted rate stays after the course. Code LINUXMAY (ends 3 May). https://monospacementor.com/courses/linsys-1
We got a feature request that would be a great improvement to our product but most likely break someone’s workflows. I wrote down how we rolled out the change without triggering a flood of angry emails.
https://monospacementor.com/2023/10/un-breaking-breaking-changes-using-feature-flags/
Ready to join a community of like-minded DevOps enthusiasts? With "The Server Room", there’s a platform for your knowledge-sharing, problem-solving, and professional development. Take the next step in your career!
Permissions in one tutorial, systemd in another, networking in a third. What's missing is how they fit together.
My course, Basic Linux System Administration, covers the whole system — permissions, services, networking, storage, security, and the connections between them. (1/2)
There's something about Rust that inspires developers to build modern replacements for traditional Unix/Linux commands. One example is `bat`, a "cat clone with wings".
https://monospacementor.com/2022/01/fsl-cool-tools-cat-and-bat/
Team efficiency can suffer from all kinds of friction. In "Don’t push harder. Reduce friction.", I describe the problems and possible solutions. Be the Zamboni that enables your team to skate gracefully!
➜ https://monospacementor.com/2024/04/team-efficiency/
📖 Interesting read: "💎 redis-objects 2.0: 17 years, 2k stars, and 16M downloads later"
https://nateware.com/2026/04/23/redis-objects-2-0-17-years-2k-stars-and-16m-downloads-later/
#ruby #opensourcesoftware
Every single DevOps or SRE job posting lists Linux. If you're serious about infrastructure work, that's where you start.
My course, Basic Linux System Administration, is where you start. Join TSR at 50% off — your discounted rate stays after the course. Code LINUXMAY (ends 3 May). https://monospacementor.com/courses/linsys-1
A blinking cursor and no instructions. That's what the command line looks like the first time.
My course starts at that cursor, and then builds from there.
Join TSR at 50% off — your discounted rate stays after the course. Code LINUXMAY (ends 3 May). https://monospacementor.com/courses/linsys-1
Basic Linux System Administration runs 12 weeks — weekly live sessions, a group of peers, a solid foundation to build on.
That's shorter than the time most people spend planning to learn Linux. Starts 11 May. (1/2)
⭐️ Interesting project: https://github.com/librepods-org/librepods
AirPods liberated from Apple's ecosystem.
Tip for Linux shell beginners: Execute a second command only if the first one was successful.
command_1 && command 2
Background: This compound command uses the result code returned by command_1 with the "shortcircuit" behaviour of the "logical AND" && operator.
🚨LIVE NOW!🚨 DevOps coworking -- Let's engineer things together! | !todo !done !tasks
Friday stream in Co-working & Studying
New blog post: "Coders have to grow"
Most Linux learning material online is years out of date. My course is kept current — updated tools, updated examples, the stuff you'll actually encounter at work. (1/2)
“A good, experienced mentor is worth their weight in gold. In fact, in many ways, it's worth prioritizing that above many other things when it comes to your career: getting that mentor.” (Martin Fowler)
I could be that mentor for you: https://monospacementor.com/engineering-mentorship/
Memorizing chmod flags gets you through a quiz. Understanding why permissions work that way gets you through a broken web server at 11pm.
My course teaches the reasoning. The commands come naturally.
Join TSR at 50% off — your discounted rate stays after the course. Code LINUXMAY (ends 3 May). https://monospacementor.com/courses/linsys-1
“I’m learning so much in my conversations on the group calls and the forum. My membership in The Server Room is paying off hugely.”
That’s Matthew, enjoying the impact of his membership on his skills and career.
Won’t you join us, too? https://monospacementor.com/community/
When something breaks at 2am, you need to know where to look — even AI can't help if you can't describe the problem.
My course teaches you to diagnose your way out. Join TSR at 50% off — your discounted rate stays after the course. Code LINUXMAY (ends 3 May). https://monospacementor.com/courses/linsys-1
Replying to
@andypiper@macaw.social @garythewilliams@mastodon.social @awfulwoman@indieweb.social @milperks@mastodon.social @Edent@mastodon.social Running Bluefin on mine, as everywhere.
🚨LIVE NOW!🚨 Linux, DevOps, SRE - Let's talk about it! | Send me your questions with !q
Thursday stream in Just Chatting