Recent content on jan0sch.de
Waybar has no default support for showing Wireguard VPN connections. There are several ways to work around this issue via the waybar-custom (see man waybar-custom ). So here is mine. ;-) 
 At first we create a helper script to more easily leverage the usage of JSON output which is then consumed by Waybar.
Something that always bothered me on DeviantArt was the missing feature to just download a gallery (for example your favourites folder) to your hard drive. Together with the what seems to be a decline of the platform (being sold, questionable moves with so called A.I.) I found it time to part ways with it. 
 The decision is older but I stayed because I never found the time to store away image…
While ScalaCheck is a powerful library that comes with quite some generators already, you need to write your own for your custom types. However I found it problematic that simply deriving generators for Cats “container” data types from existing ones is not included.
After upgrading some workstations from 14.0 to 14.1 the microphone (audio recording) in Firefox stopped working. This came as a surprise because it worked for years without any issues. So, time to do some debugging! :-)
I even cannot remember why I started using the ssh daemon from ports (openssh-portable) but it might have been some feature I needed at that time. 
 However, ever since then one of my first things done on a fresh install was disabling the base sshd and replacing it with the one from ports. 
 Thinking about it recently I realised that this very likely a pretty dumb idea, so I checked if I…
If you upgrade your FreeBSD installation you should also upgrade your bootloader (bootcode) too. However in many cases you don’t need to, so you might never have done it. ;-) However if you’re booting from a ZFS pool which you upgrade to a newer version than the bootloader can handle then you’re in for trouble. 
 An example is upgrading directly from FreeBSD 13.2 to 14.0…
Recently I got inspired to try out the December Adventure and so here we are. ;-)
It has been nearly two years now since I switched from Sylpheed to aerc as my daily driver for email. 
 While Sylpheed still is an awesome email client my switch was triggered by more heavy usage of a laptop than before and the discovery of usability problems I thought long solved like: 
 
 very high resolution but applications either zoomed / scaled which results in less space than…
The default expectation of the wonderful aerc email client is the usage of abook as address book. Also most people seem to use calcurse for calendars. However what if we want to switch?
Some of us prefer to use console (text terminal) tools for productivity and that is just fine. In this tutorial we’ll explore how to synchronise address books and calendars via the DAV protocols for the khard address book and the khal calendar .
The trouble started when emails were coming in claiming first “Fail” and later “DegradedArray” events of a software raid running on a Debian Linux server. Looking into logs revealed an SSD (NVMe) died but let us look at it step by step.
Because setting an environment variable via a shell init file doesn’t seem to be en vouge in modern linux distributions we need to find other ways. To spare you breaking precious hardware in the process here is the solution: 
 You can define “.conf” files within the directory ~/.config/environment.d/ that may contain one variable definition per line and out of these the…
With the release of version 1.9.0 
sbt is deprecating the IntegrationTest configuration. Read on to learn how
to migrate to tagged tests instead. 
 While the recommended migration path is to create a subproject in which you
pool all your integration tests, I respectfully disagree and suggest to use
tagging to filter tests during test runs.
For quite a long time PostgreSQL supports authentication via SCRAM-SHA-256 now,
so migrating is long overdue. This small guide will show you how to do this. 
 The support for SCRAM-SHA-256 was introduced in version 10 of the PostgreSQL
database and it is the default for freshly installed systems since version 13. 
 Since it is not only used for internal storage of password hashes…
Without further configuration you will not be able to put a widget from TeamCity
onto a dashboard in Hub. Usually you can create a widget but it will not load
any data complaining about “Cannot load project list” or something similar. 
 The reason for it is that some
 CORS 
configuration on the TeamCity side is needed.
VCS usually have hooks into which commands can be “plugged” to be executed automatically upon certain events and the great darcs is no exception. 
 Having your code checked for formatting guidelines before you record (commit) it is quite convenient and so let us implement a prerecord hook for darcs that instruments sbt to check you code style.
There are scenarios when you might want to automatically create snapshots via ZFS to have a backup ready if needed. The features of ZFS make this straightforward and easy.
However this also means that you might run into trouble because of having too many snapshots.
It is nice if your CI/CD pipeline does also check for code format compliance but sometimes you may want to have feedback earlier or even prevent unformatted code to enter the repository. 
 In such a case the git DVCS offers hooks to the rescue. You can either dive into their documentation or simply use the script provided below. ;-)
Sometime you need or want to move a commit or several of them between
different git branches. One possible scenario would involve a created feature
branch which runs a bit longer and multiple important fixes have been made on
it. Some might argue that this shouldn’t happen but guess what: this happens
all the time. ;-)
For some time now the usage of metals for
Scala development is no longer a choice for the brave but could be
considered the “should be default” variant. However the installation for the
neovim plugins has changed from using coursier bootstrap to something
supposed to be easier. But at least under FreeBSD I ran into some issues.
So here is a workaround to get a clean…
Gitea is a nice alternative for a self hosted Git
service. However there is no official support for it in the
 TeamCity build and continuous
integration server.
Some days ago I ran my regular pkg upgrade command under FreeBSD and lost
my input devices under X11 (Xorg). :-( 
 However with help from several people we were able to find a fix for it.
My colleague Maali discovered an issue that raises its ugly head if you’re
using the typesafe config library in
combination with Cats effect and
certain versions of SBT .
Today I finished my book about “Pure functional HTTP APIs in Scala”! 
 This book is intended for the intermediate Scala programmer who is interested in functional programming and works mainly on the web service backend side. Ideally she has experience with libraries like Akka HTTP and Slick which are in heavy use in that area. 
 However maybe you have wondered if we can’t…
Bereits vor einiger Zeit wurde die Gruppe LambdaHRO von mir mitgegründet. Wir versuchen uns jeweils den zweiten Donnerstag im Monat ab 18:00 Uhr zu treffen. 
 Die Gruppe LambdaHRO (λHRO) wurde gegründet mit dem Ziel den Austausch zu den Themen Softwareentwicklung und Informatik mit Fokus auf die funktionale Programmierung zu ermöglichen. 
 Schaut auf der oben verlinkten Webseite vorbei,…
Quite some time ago I started noticing that the mouse in dosbox was starting to “jump” occasionally. But since I don’t get to play games quite often I ignored and filed it under “possibly driver issues”.
This is an updated version of my previous guide and reflects the latests
changes in the scala ecosystem. So if you would like to use
 neovim for your Scala 
development work flow then this guide will get you started. 
 Because ENSIME is dead and gone we will use the
 metals language server for Scala.
Unser Buch “Come out and Play” über Webentwicklung mit Scala, Scala.js,
Akka und dem Play Framework ist fertig. 
 Die finale Version kann bei LeanPub: https://leanpub.com/comeoutandplay erworben werden. Alternativ auch bei Thalia: https://www.thalia.de/shop/home/artikeldetails/ID151410922.html oder Amazon: https://www.amazon.de/dp/B09317XB5J und anderen. 
 Mit diesem Buch…
Was lange währt, wird endlich gut - so sagt man jedenfalls. ;-) 
 Heute haben wir die erste Version unseres Buches “Come out and Play”
veröffentlicht: https://leanpub.com/comeoutandplay . Alternativ via Thalia: https://www.thalia.de/shop/home/artikeldetails/ID151410922.html oder Amazon: https://www.amazon.de/dp/B09317XB5J zu haben.
Es handelt sich um ein Fachbuch über…
Das Thema Datensicherung (Backup) ist ein großes und jeder, der sich
ernsthafter mit Computertechnik beschäftigt, sollte damit Berührung gehabt
haben. Im Guten wie im Schlechten. ;-) 
 In dieser kleinen Anleitung möchte ich kurz beschreiben wie man mit wenig
Aufwand in die Lage versetzt wird die Snapshots von ZFS zu nutzen, um
verschlüsselte Sicherungen auf eine externe…
If you would like to use neovim for their
 Scala development workflow then this guide
may get you started. 
 It is possible to simply edit the source files but some configuration and
plugins will make your workflow way more productive. This includes using
projects like ENSIME ,
 SBT and several plugins for neovim.
Because there are way to many options for git 
to remember it is feasible to have a template file for the .gitconfig 
which is usually located in the home directory.
If you’re upgrading your FreeBSD installation to 11.2-RELEASE please ensure
that you disable custom kernel modules first. The usual suspects are the
nvidia driver and the virtualbox kernel module.
In some cases you may need the sources (kernel source) for your FreeBSD
installation. However if you did not select the source package in the
installer it will not be installed.
Als alter Leseratte begegneten mir viele Bücher, von denen ich einige
empfehlenswerte hier aufführe. Vielleicht findet der eine oder andere
eine Anregung für die eigene Lektüre .
Da ich recht viele Filme sah/sehe, hielt ich eine solche Liste für eine
gute Idee. 
 Zum echten Cineasten fehlt mir allerdings das Sitzfleisch. :-) 

Erstaunlich ist immer wieder was man in Sachen Grafik seit Beginn der
1990’er Jahre so aus dem guten alten C64 rausgeholt hat. Wer Grafiken
konvertieren oder sonstwie einlesen möchte (Scanner, Digitizer), der sollte
sich unbedingt GoDot ansehen!
Dieses Programm ist wirklich eine feine Sache. :-) 
 Auf der GoDot-Seite sind auch Grafiken von mir zu finden. Ansonsten…
Der Film “Rogue One” ist ein Science-Fiction aus dem Jahr 2016 und
erzählt die Vorgeschichte zum Film “Star Wars” (Episode IV). Regie
führte Gareth
Edwards und
in den Hauptrollen spielen Felicity
Jones , Diego
Luna und Ben
Mendelsohn sowie Forest
Whitaker . 
 Auf einem abgelegenen Planeten lebt Galen Erso als Farmer mit seiner
Frau…
If you’re running confluence behind a reverse proxy then you might stumble upon an issue that prevents firefox from working correctly. Strange bugs will hapen like clicking on “add a new page” resulting in endless loading loops.
If you work with sbt (or activator) and want to restrict the resolvers to the ones that you choose then you might get frustrated that overriding the resolvers setting does not suffice.
If you happen to use the fine postgres extension for slick named slick-pg then you might stumble into an issue where the compiler complains about missing implicits for column types that should be provided by slick-pg if you override the api method of the custom postgres driver.
If you ever need to change the author of a commit (or several) within a git repository, you can use the following script:
If you’re using the fabulous wartremover to keep your code cleaner and are using akka too then you might have stumpled upon the following warning from wartremover:
If you upgrade cups on your FreeBSD installation or maybe you install some foomatic packages this may lead to the removal of the cups-filters package. In some cases this package is needed for your printer to work correctly.
Non-Stop ist ein Action-Thriller aus dem Jahr 2014. Regie führte Jaume
Collet-Serra und in den Hauptrollen spielen Liam
Neeson , Julianne
Moore und Michelle
Dockery . 
 Air Marshal Bill Marks (Liam Neeson) wird auf einem Flug von New York
nach London eingesetzt. Als er kurz nach dem Start eine Nachricht
erhält, daß alle 20 Minuten ein Passagier getötet wird, wenn nicht…
The prompt of lftp can be configured in the config file via the
 set prompt directive. A while ago I found a prompt on the internet but
forgot where, here it is:
Das Kartell (Clear and Present Danger) ist eine amerikanischer Spionage-Thriller aus dem Jahr 1994. Regie führte Phillip Noyce und die Hauptrolle spielt Harrison Ford . Es handelt sich um eine weitere Verfilmung der Buchreihe über den CIA-Agenten Jack Ryan von Tom Clancy . Die Rolle von Vizeadmiral James Greer spielt wie in den anderen Filmen auch James Earl Jones . 
 Agent Ryan stellt fest,…
The start menu of Windows 10 displays some stuff from the internet by default. If you find this annoying like me then feel free to follow this guide to fix that.