cron.weekly issue #95: fail2ban, React, $HOME, apt-key, Go, Kanban, Zabbix, Zsh & more

cron.weekly is a newsletter about Linux, open source & webdevelopment. Want to get it in your inbox every Sunday? Subscribe below!

I respect your privacy and you won't get spam. Ever. Just a weekly-ish newsletter about Linux and open source.
Image of Mattias Geniar

Mattias Geniar, August 27, 2017

Follow me on Twitter as @mattiasgeniar

Welcome to cron.weekly issue #95 for Sunday, August 27th, 2017.

Lots of variation in this issue again, from the deep-technical guides and projects to more ‘soft’ talks about open source licensing, anniversaries & history of Linux.

Happy Sunday all!


An OSI layer model for the 21st century

This is a fun exercise to try and rethink the OSI layer for today’s standards, keeping security & cryptography as one of the primary motivators.

This is a fun in-browser shell simulator with a a lot of challenges to get through.

Premier Open Source Database Conference

Join the Open Source Database Community 25-27 September, 2017, in Dublin for Percona Live Europe. With various talks covering core topics on MySQL, MongoDB, MariaDB, PostgreSQL, Time Series Databases, RocksDB & more. 1 day tutorials & 2 days sessions & keynotes. Buy Now(Sponsored)

Facebook’s BSD+Patents License and how it affects your company or side-project

There’s been a lot of talk in the last few weeks about Facebook’s React project and their licensing model. This post tries to decipher the consequences, and the worst-case scenario isn’t all that great. Let’s hope that particular scenario doesn’t happen (or get enforced).

Explaining React’s license

In this post, Facebook themselves explain why they didn’t change their license after the Apache Foundation requested it. I’m not sure what to make of this, as everyone defends their own point of view, obviously.

GoCD – open source continuous delivery

GoCD is a continuous delivery tool specializing in advanced workflow modeling and dependency management. New AWS ECS elastic agents plugin just released. Optimizes your utilization and reduces infrastructure cost now. (Sponsored)

Why PS4 downloads are so slow

This isn’t necessarily Linux related, but it was a fascinating read regardless: the author looks at why download speeds on a PS4 are slow and takes a deep technical look at TCP receive windows, congestion, round trip times, … fascination read for those of us who care about networking.

Happy anniversary, Linux: A look back at where it all began

Linux turned 26 last week! In this post, the author looks back at one of the earliest Linux distributions – Softlanding Linux System (SLS), reinstalls it and compares that kernel with today’s most modern Linux kernel.

Debian turns 24

I’m actually a week late but I missed this news last week: happy birthday, Debian!

Why ~ is the symbol for $HOME

It’s all got to do with hardware. Click through if you want to know some Linux trivia about that tilde representing the $HOME directory.

On piping curl to apt-key

The `curl | bash` method is generally frowned upon, but this post looks at what might go wrong if you go `curl | apt-key`, too.

Tools & Projects

Datadog: all your infrastructure, in one place

Track & alert on the health and performance of every server, container, and app in any environment, with Datadog. Sign up for a free 14-day trial(Sponsored)

Awesome Linux Software

This repo has a collection of pretty much every major Linux project, from audio editing to chat, development & productivity and everything in between. If I’m every out of ideas for new projects to highlight, I’ll have a look there. ^^


Bare metal, self-hosted, self-healing/provisioning, mesh network kubernetes cluster.

Planet OpenBSD

This project aggregates many OpenBSD related blogs and newsfeeds into a single view. If you’d like to keep track of OpenBSD related work, this might be something for you.


OpenFaaS is a framework for building serverless functions with Docker which has first class support for metrics. Any process can be packaged as a function enabling you to consume a range of web events without repetitive boiler-plate coding.


Auto-sync files or directories over SSH using rsync and


Wappalyzer is a cross-platform utility that uncovers the technologies used on websites. It detects content management systems, eCommerce platforms, web servers, JavaScript frameworks, analytics tools and many more.


A new set of free and open icons to use.

clarity icons

Lots of open source & free icons to use on websites or other projects, this time by the VMware team.

Go 1.9

Most of the engineering effort put into this release went to improvements of the runtime and tooling, which makes for a less exciting announcement, but nonetheless a great release.


Tarantool is an in-memory database and application server, a drop-in replacement for Lua with non-blocking I/O.


How to be agile as a terminal geek? In Bash, of course! This is a commandline asciii kanban board for minimalist productivity bash hackers (csv-based).


The Node project forked, yet again. Not sure on the viability of this one (seems to only be supported by a handful of people), but if it turns out to eventually surpass Node, I want to make sure I included it. ^^


Prezto is the configuration framework for Zsh; it enriches the command line interface environment with sane defaults, aliases, functions, auto completion, and prompt themes.


Cuberite is a Minecraft-compatible multiplayer game server that is written in C++ and designed to be efficient with memory and CPU, as well as having a flexible Lua Plugin API. Cuberite is compatible with the vanilla Minecraft client.


Easily create a microservice for generating PDFs using headless Chrome. pdf-bot is installed on a server and will receive URLs to turn into PDFs through its API or CLI. pdf-bot will manage a queue of PDF jobs. Once a PDF job has run it will notify you using a webhook so you can fetch the API.

Zabbix 3.4

A big new release for the monitoring tool, featuring a new dashboard, better timing & correlation of metric retrieval (aka: get all CPU perf counters at once, instead of one at a time), many server-side improvements, notifications on alert ack’s, multi-threaded alerting, … very cool stuff all!

Fail2ban 0.10

It took almost 6 years to get a new release for fail2ban, but it’s a good one: support for IPv6, faster lookups by searching the fail of logfiles, improved filters, … the Changelog is pretty big.

Guides & Tutorials

A Tutorial on Portable Makefiles

This post contains a lot of good details on how to make & maintain a Makefile in order to have a structured & sane build config.

Improving Cloud Security Visibility with ChatOps

An interesting approach where API calls to AWS get logged & triaged into “noise” and “important” and in turn get pushed to the engineer that made the call, to confirm he/she did that on purpose.

Extended File Attributes Rock!

There’s more to Linux user permissions than user/group/other and read/write/execute. Extend file attributes gives you lots of flexibility regarding user & group permissions and are definitely worth a look if you haven’t used them.

Docker Cheat Sheet

Lots of practical Docker-related commands to help get you started & serve as a reference guide to fallback on.

Zsh Configuration From the Ground Up

A lot of good configuration tips in this post, together with a clear explanation on why to use those values/settings when setting up your Zsh shell.

Want to subscribe to the cron.weekly newsletter?

I write a weekly-ish newsletter on Linux, open source & webdevelopment called cron.weekly.

It features the latest news, guides & tutorials and new open source projects. You can sign up via email below.

No spam. Just some good, practical Linux & open source content.