cron.weekly issue #101: GitLab, yes, true, Postgres, doitlive, tmux, systemd & more

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Mattias Geniar, October 15, 2017

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Welcome to cron.weekly issue #101 for Sunday, October 15th, 2017.

Depending on your timezone & when you read this: good morning, good afternoon or goodnight!

It feels good to be back on a regular schedule, so plenty of variation in this issue again. Some open source games, Linux trivia & oldskool Unix tricks with key combinations at the console.

Happy reading!


Origins and History of Unix, 1969-1995

This goes way back, to the very first Unix systems created at Bell Laboratories. Pretty fascinating piece of history!

GitLab raises $20M Series C round led by GV

Another open source giant that’s raising serious cash, this time to GitLab.

Rage4 DNS

Authoritative DNS for pros – anycast, GeoDNS, failover support with monitoring integration, DNSSEC, DANE/TLSA, CAA and much more. Join now, open support ticket and receive 10% discount as cron.weekly subscriber. (Sponsored)

A Little Story About the `yes` Unix Command

Did you know the ‘yes’ command is actually crazy fast? The trivial program yes turns out not to be so trivial after all.

Debian devel: Let’s enable AppArmor by default (why not?)

There’s currently a proposal to enable AppArmor on Debian testing/sid, with the goal of making this the default setting in roughly 1 year.

Instant ADD COLUMN for InnoDB

Ever had to add a column to a 100GB+ table in MySQL? It’s a pain and can take hours. So I’m very pleased to read that MariaDB 10.3 (which isn’t out yet) will support instant ‘ADD COLUMN’ statements, adding new columns in milliseconds.

The /bin/true Command and Copyright

Back in the ’80s and ’90s, AT&T copyrighted the ‘true’ command, which consisted of nothing but comments and blank lines, no actual code.

The space station gets a new supercomputer

And it’ll run Red Hat Enterprise Linux 6.8!

Exploding Git Repositories

The tar- or zip-bomb reimplemented as a git repository, so if you “git clone” this one, chances are your OOM killer will be invoked. Clever!

Dear Postgres

An homage to Postgres, looking back at the accomplishments in the last decade.

Tools & Projects

Get full-stack observability with Datadog

Go from a global view of your infrastructure to inspecting an individual request trace, all in one developer-friendly platform. Start a free 14-day trial. (Sponsored)


fd is a simple, fast and user-friendly alternative to find. While it does not seek to mirror all of find’s powerful functionality, it provides sensible (opinionated) defaults for 80% of the use cases.


mailproxy is a simple SMTP proxy. It receives emails through an unencrypted, unauthenticated SMTP interface and retransmits them through a remote SMTP server that requires modern features such as encryption (SSL, STARTTLS) and/or authentication (SMTP AUTH). mailproxy is primarily useful for enabling email functionality in legacy software that only supports plain SMTP.


This is pretty cool; doitlive is a tool for “live” presentations in the terminal. It reads a file of shell commands and replays the commands in a fake terminal session as you type random characters. It essentially let’s you prepare “live demo’s” in pre-recorded sessions.


TorProxy is kernel module which routes all network traffic through the Tor anonymity network.The module uses netfilter hooks in the linux kernel to filter/NAT packets and ensure all outbound traffic is headed for the Tor network.

Tmux workspace generator

Cockpit is a HTML5 app to create panes and windows in Tmux. Configure your workspace, download the script and run it.


This is very powerful and can have big potential: rat let’s you compose shell commands to build terminal applications. Shell commands are executed and the output is captured and displayed in pagers. Configurable annotators parse through the output, adding annotations that can be acted upon to run other shell commands. This is best explained with the little gif/video on the README page.


Bolt is a Ruby command-line tool for executing commands, scripts, and tasks on remote systems using SSH and WinRM.

Rollercoaster Tycoon 2

An open source re-implementation of RollerCoaster Tycoon 2.

Open Source Game Clones

Following up on the RT2 from above, here’s a full list of open source clones of games (think Age of Empires, Alone in the Dark, Doom 3, … aah #nostalgia).


Etcher is a powerful OS image flasher built with web technologies to ensure flashing an SDCard or USB drive is a pleasant and safe experience. It protects you from accidentally writing to your hard-drives, ensures every byte of data was written correctly.


Let’s face it, most WYSIWYG editors on the web suck. This one looks promising, it’s a toolkit for building rich-text editors on the web.

Guides & Tutorials

You can’t buy DevOps, but you may have to sell it – GoCD

This new blog series aims to help DevOps leaders in organization get stakeholder buy-in. It covers approaches to talking about why, as well as specific things you can do to sell your ideas. (Sponsored)

10 Linux Commands Every Developer Should Know

This post covers file, iotop, tee, pidof, txmux, tree, chroot & dialog – each tool described very briefly, but gives enough of an overview to get a general idea what they do.

An Awk Primer

This book covers everything you need to know about Awk, all published on a Wiki. From arrays to control structures to variables & in- and output, it’s all there.

IP Accounting and Access Lists with systemd

Systemd lets you do per-unitfile IP accounting, so counting bits & bytes in + out per unit you configured. This can replace a lot of hacky setups where you want per user or per service bandwidth billing, like shared hosting.

Magic SysRq key

On this page, all Alt+SysRq+key combinations are shown that you can use at a Linux console. This includes the ability to reboot, call oom_killer, send SIGKILL’s, … all from a convenient keyboard shortcut. Worth a look!

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