Schlomo Schapiro

Software rules the world, and everybody is its subject. But you can be a ruler, too - if you like  I keep telling my family. Here is a little example where I try to rule my secondary printer by automating the tedious task of rotating and scaling content to print. My Little Zebra Printer My secondary printer (shown here on the shelf in my home office) is a little miracle device: It is a thermal transfer receipt printer , that prints on a roll of continuous paper that is 10cm (4in) wide. Specifically a Zebra GX420d . You can get such a used printers relatively cheap. This is exactly a printer like you know from your local supermarket. And it is a super useful tool to have at home, as many print jobs don't require a full A4 page and don't need to be printed on fancy bright white paper with ever-lasting toner. Most common print jobs are shipping labels (no need to cut them to size), small shopping lists (fits in a pocket), little notes to stick into a book (e.g. reading order for ...

Our door bell is not very loud and we don't hear it in the kitchen when the internal doors are closed. We already missed people calling at our apartment door because of this. To solve this problem I found a 10€ remote bell that sits in the kitchen and rings whenever somebody rings our door bell. Initially I wanted a fancy WIFI based solution based on an ESP32 that would call me via SIP... But in the end this simple solution is "good enough" and has the benefit of zero maintenance. My solution is based on a kinetic wireless doorbell  (batterielose Funktürklingel) that has two components: A ringer that sits in a power socket and a transmitter without batteries. The "without batteries" part is really important as it allows a direct connection and integration of the transceiver into the door phone. As it happens, what I needed was available for 10€ at a local supermarket, but you can easily find this type of doorbell in online stores as well. The ringer contains a l...

SSH keys are considered to be a security feature, but sometimes they make things more complicated than necessary. Especially in automation contexts we use SSH keys without  a pass phrase which degrades the security of the SSH keys to the security level of a plain text password. The only benefit of the SSH keys is the fact that an attacker who gains access to the server won't be able to use the keys found there to login somewhere else. As such SSH keys are still better and more secure than having a regular plain text password. In automation contexts we sometimes have to handle lots of SSH keys, for example with GitHub Deploy Keys . GitHub mandates to use a different SSH key for every repository to ensure that a leaked private key will not lead to a breach of other repositories. I recently had to configure a Go Continuous Delivery server and it turned out that it does not support managing SSH keys at all (like Jenkins or TeamCity do). In order to still be able to us...

I do a lot of pair working and many times I connect a large TV or projector to my laptop for others to see what I am doing. Unfortunately the display resolution of my laptop never matches that of the other display, and Linux tends to choose 1024x768 as the highest compatible resolution. This is of course totally useless for doing any real work. My preferred solution for this problem is to use X scaling to bridge the resolution gap between the different screens. Since none of the regular display configuration tools support scaling, I ended up typing this line very often: xrandr --output LVDS1 --mode 1600x900 --output HDMI3 --mode 1920x1080 --scale-from 1600x900 Eventually I got fed up and decided to automate the process, the result is automirror , a little Bash script that automatically configures all attached displays in a mirror configuration. automirror is available on  https://github.com/schlomo/automirror . Typical Use Cases Connecting a Full HD 1920x1080 disp...

If you work at an agile shop you probably have seen something like this: You also find a lot about how people create those nice dash boards as a web page, but you almost never find out how to actually build the system that runs the dash board. Basically this is a task for digital signage, but "standard" solutions like Xibo seem heavily oversized for running an internal dash board. All we need is a Linux box running a browser and the screen staying on. As my team also wanted to have a dashboard, I  recently hat to build one and decided to put my effort into an Ubuntu package named  kiosk-browser  that can be found on the ImmobilienScout24 github page. The package turns a regular Ubuntu installation into a web-based dashboard. Now the effort to setup a new dashboard system has been reduced to these steps: Install a computer with Ubuntu. Build or download and install the kiosk-browser package.  Log on as a user and run this command: sudo tee /etc/defa...

At the Desktop Summit I stood almost 2 hours in the yard talking to Michael Bell and amongst many other things we got an idea about how to solve the problem of Desktop backups in large environments. The basic idea is to go away from a centralized approach and solve the problem with a peer-2-peer solution. The main benefit is scale-out vs. scale-up: As the amount of Desktops that require a backup grows, so does the amount of Desktops that provide backup space.

My colleagues at ImmobilienScout24 released the main part of our new deployment solution YADT - an Automated Deployment Tool . Check out the code at our Google code homepage . Documentation and proper packages will follow soon.

Today I released the first part of our new Open Source Project YADT - an Augmented Deployment Tool . The configuration management with the help of RPM packages and a subversion repository is now available via the project repository . At the Subversion Day Berlin 2011 I gave a talk about how we do configuration management with RPM packages at ImmobilienScout24: Me showing the ImmobilienScout24 recruiting slide (Picture courtesy of H. Klotz) Download the slides as PDF for details: Subversion Day Berlin 2011 - Configuration Management with Subversion and RPM.pdf Read my conference reports: Subversion Day at Heise Developer SubGit at Heise Open

I just gave my talk at the LinuxTag 2011 about Self Service Virtualization as private Cloud and my new Open Source project Lab Manager Light . From the audience of about 80-100 people there where quite a few interesting questions and also several "I wish you had done that last year" comments. Download the slides: LinuxTag 2011 - Lab Manager Light - Self Service Virtualization as a Private Cloud.pdf