Category Archives: software

The terminal multiplexer tmux is a very useful and versatile tool. One thing that it apparently can’t do, however, is to automatically log a session to a log file. Such a feature can be very useful for interactive workloads. Sidenote: tmux also has a plugin manager and there are logging plugins available, but they don’t do exactly what I want. The manual way Logging all inputs/outputs can be done with a simple command: Manually executing this command at the creation of a pane, e.g. the start of a new session is possible but let’s be honest: I will forget it the next day already. So, an automatic method is needed. How it should work but doesn’t Tmux has hooks that trigger actions when certain events happen. The after-new-pane or after-new-session hooks would be ideal to execute the logging command whenever a new session or pane is opened. Adding the hook…

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Working on AWS projects in the terminal can be annoying sometimes, especially when you have a large list of accounts and roles to work with. Typing in the multi-part command and the role ARN is just too much work to do over and over again:aws sts assume-role –role-arn arn:aws:iam::123456789012:role/roletoassumeDefining an alias for each role is impracticable, as well, because it would require to edit the AWS CLI config file (~/.aws/config and ~/.aws/credentials) and update the aliases (~/.bash_aliases or similar depending on your shell). It would be so much easier if the assume-role command would just query the AWS config. Just like this: The solution is the little helper programm assume-role in combination with fzf. Installation and setup The following assumes bash as your shell of choice and aptitude as the package manager. Other shells or package managers work just as well. AWS CLI Download and install AWS CLI: This covers…

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A working approach on how to migrate a network Time Machine backup.

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In 2018, a colleague mentioned to me that he found a nice CO2 monitor with an undocumented but open USB connection. On Github, vfilimonov wrote a nice python package to decode the USB connection and show the measured data on a website. From this starting point on, I experimented with further sensors and a more complex data acquisition, storage and visualisation. The current state is an experimental setup running on a Raspberry Pi 3B+. Several sensors are connected to test and compare them. Connected sensors are: TFA Dostmann AirCO2ntrol Mini CO2 Monitor Two DHT22 temperature and humidity MH-Z19 IR absorption CO2 sensor 0-5000ppm TSL 2561 light intensity sensor BMP280 digital barometer The monitoring system in the configuration as used in the following. Raspbian Buster runs from an old SSD that also stores programs and databases (black cable with two USB port because the Pi cannot supply enough current). The white…

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As mentioned in the introduction to the homeclimate monitoring project, I run a small unRAID homeserver with a couple of disks to provide some services in my local network. Besides monitoring the server itself with the TIG stack (Telegraf, InfluxDB, Grafana), it is also interesting to monitor power consumption to find out what the server costs aside from the initial cost for the hardware. Self-made solutions operating on mains voltages is always tricky and the potential risks are large. Luckily, there are a number of cheap and easy commercial options. I opted for the “TP-Link Kasa smart plug HS110” which is available online for typically less than 20€. The HS110 can monitor voltage, current, power and turn on/off the integrated outlet remotely. It also has smart home feature (e.g. Alexa skills, Google Assistant, IFTTT) but I don’t need nor want those. Still, it is one of the cheapest and also…

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