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required features Java Database Connectivity and one of the followoing features: Java Persistence API, includes Eclipselink as provider, or Java Persistence API Container, for other providers like hibernate plus a JPA provider configuration configuration…

complete TLS setup for Openliberty with keystore creation and setup of Root CA

@FacesConverter does not work with the JSF 2.3 feature of Openliberty with a default config

mounting a ramdisk at boot up and differences between tmpfs and ramfs

installation of the JDK / JSDK – the Debian way

configuring the keyboard with a layout alternating between a primary and a secondary language

controlling cursor position, text attributes and screen display with tput

how to compile and install a new kernel and how to remove unused kernels

using udevil and devmon for automatic mounting of removable media

alternate mounting of several devices under the same mount point

management of keys for partitions encrypted with LUKS

two ways how to prevent kernel modules from being loaded at startup

how to run diagnostics of devices encrypted with LUKS

fix for stalled shutdown process on Debian systems with System-V Init

how to set up encrypted partitions with LUKS after installation of the OS

shellcheck Check shell scripts with ‘shellcheck’ print out executed expression Test shell scripts with the ‘-x’ switch:

Expressions like <expr> are still prevalent in the wild.

locking with homegrown solutions and the command dotlockfile

working with file descriptors and reading files in a shell script with the read command

how to trap signals that are sent to your shell script and how to handle them properly

In Bash shell programming you can use the usual suspects for loop structures: the for loop, which is usually used to

general form of test expressions, i.e. for loops and if statements

how to work with functions – or what is sold to you as functions in shell programming

types of shell commands There are four types of shell commands: shell builtin – commands, that are built into the shell. test and printf are more often than not shell builtins.

A 2nd order reference is a reference that references the variable with the name which is the value

welcome to the world of negative indices and other barnyard oddities.

There are several methods for the parsing options / parameters supplied to the shell script .

how to run the HUGO server in dev mode, for deployment, and within scripts

configuration of the Java Security API’s HttpAuthenticationMechanism on Payara

some recommended basic configuration after the installation of PostgreSQL

some useful psql commands for daily work with PostgreSQL

creating databases and database objects

using script files for automatic creation and preseeding of databases

making databases more manageable and more comprehensible with schemas

I work on Linux and my favourite setup for development is Intellij, Git and the Atlassian tools for collaboration: BitBucket, Bamoo, Jira, Confluence.

Elegance is not a luxury but a prerequisite for stable and equally flexible systems.

In most projects I’m working 20% as an architect and 80% as a developer, building prototypes and POCs, implementing functionalities and reducing complexity.

In the Enerchain project, I supported the B2B service provider Ponton, Hamburg, in setting up a decentralized trading platform for energy suppliers.

I supported the team at Silpion, Hamburg, in developing the internet portal for the PES (Party of European Socialists).

When Volkswagen developed its own car radio system, I joined the development team and was responsible for the AM/FM part of the car radio.

For Ingenico, one of Europe’s largest payment service providers, I developed a catalog of measures for modernizing a helpdesk application for first-level support.

I supported Navteq, a leading provider of geographic data for use in navigation devices, in the further development of a GIS (Geographic Information System).

just a quick example of how to generate a view from three tables

creation and maintenance of users and roles, setting permissions for users and roles