cron.weekly issue #139: VPN, Guix, expose, lynis, tor & more

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Mattias Geniar, June 21, 2020

Follow me on Twitter as @mattiasgeniar

Hi everyone! 👋

Welcome to cron.weekly issue #139.

Back to our regular schedule of Linux, open-source & webdev news!

Grab a ☕️ and enjoy this issue.

News & general 🗞

Introducing Firefox’s Mozilla VPN

Firefox will soon ship with an optional, $4.99/month, VPN service. Could this be the moment where wide adoption for VPNs finally becomes mainstream?

If so, what would the implications be for services that rely on IP-to-country checks, location-aware advertising, man-in-the-middle ad-injections, … ? Fun stuff to think about!

Why is there a “V” in SIGSEGV Segmentation Fault?

A bit of trivia which I’ll summarize if here for you. #SavedYouAClick

[…] the signal name stands for “Segmentation Violation”.

So it’s essentially: SIGnal SEGmentation Violation.

But there’s more!

Originally the signal was called SIGSEG. It was subsequently renamed SIGSEGV in the userspace and a bit later - around 1980 - to SIGSEGV on the kernel side.

Now you get to brag to your developer colleagues that you, a seasoned Linux sysadmin, know where SIGSEGV came from. 😎

Flatpak - a security nightmare

Red Hat’s flatpak has been getting a lot of attention lately, it’s the self-proclaimed new way of distributing desktop applications on Linux. But as this author proves, there are some security concerns …

Guix Further Reduces Bootstrap Seed to 25%

I first learned about the Guix project at the Breaking Bitcoin conference in Amsterdam last year and have been fascinated ever since.

They try to answer one of the more difficult questions in open source: can you trust your compiler and build system?

They’ve now been able to remove GNU Awk, Bash, Bzip2, the GNU Core Utilities, Grep, Gzip, GNU Make, Patch, sed, Tar, and Xz from the build system. It’s been replaced by Gash and Gash Core Utils instead.

Adobe Flash Player End of Life

A good reminder that the Flash Player will go end-of-life and this end-of-year, 2020.

If you’re still relying on Flash to distribute your application or content, well … err … well yes … I’m sorry for you.

Zsh and Fish’s simple but clever trick for highlighting missing linefeeds

This is was a far more interesting read than I would have though. 😄 I didn’t even realize the terminal was such a complex tool when it comes to interpreting command output!

Tools & Projects 🛠


Expose is a completely open-source ngrok alternative - written in pure PHP. It’s a tunnel application that allows you to share your local websites with others via the internet. 😍

Apache Spark 3.0

Spark is a unified engine for big data processing, data science, machine learning and data analytics workloads. Feature highlights in Spark 3.0 are: adaptive query execution; dynamic partition pruning; ANSI SQL compliance; new UI for structured streaming; up to 40x speedups for calling R user-defined functions; accelerator-aware scheduler; and SQL reference documentation.


Lynis is a security auditing tool for systems based on UNIX like Linux, macOS, BSD, and others. It performs an in-depth security scan and runs on the system itself. The primary goal is to test security defenses and provide tips for further system hardening.

Kubernetes cluster for under € 10 per month

With Hetzner Cloud, you can set up your own simple 3 node Kubernetes cluster from scratch for under € 10. An official cloud controller manager for Kubernetes is available on GitHub.

The multi-purpose cloud servers made in Germany are located in the company’s own state-of-the-art data centers. Sponsored


This repository is for the GitHub Action to run a Super-Linter. It is a simple combination of various linters, written in bash, to help validate your source code.

HetrixTools - Free Uptime Monitoring

Monitor your websites and servers every minute from around the world, and receive alerts as soon as any issues are detected, helping you minimize your downtime by being the first to know about it.

Start off with 15 Uptime Monitors, checked every 1 minute, completely free forever! Sponsored

CentOS 8.2.2004

This new CentOS release, based on RHEL 8.2, introduces Python 3.8, new compilers for gcc/go and a bunch of bugfixes in packages & the kernel.

FreeBSD 11.4

This is the fifth and final release of the stable/11 branch. Updates include: the clang, llvm, lld, lldb, and compiler-rt utilities as well as libc++ have been updated to upstream version 10.0.0, openssl & unbound package updates, ZFS improvements & plenty more.


GitRows makes it easy to use and store data in GitHub and GitLab repos. You can read data stored in .csv and .json files from all public repos and read, create, update and delete data in public or private repos that you have access to, all with the benefit of version control.

Guides & Tutorials 🎓

Practical Python Programming

A free course on writing modern & practical Python.

Operating a Tor Relay

The Tor network is operated by volunteers worldwide, that donate bandwidth and server capacity to allow users to anonimize their bandwidth. This write-up shares the technical setup involved.

Back in 2015 I also experimented with a Tor node (not an exit node), if you’re interested I have some graphs/words about that here.

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