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Flash Arduino without a Bootloader from a Raspberry Pi

tl;dr: use the GPIO pins of a Raspberry Pi to flash Arduino boards without a bootloader

To keep things short: I’ve had an Anet A8 3D printer for a while now and wanted to flash an updated version of its Marlin firmware. For some reason however, the bootloader was broken. So I couldn’t flash it with avrdude by simply using a USB cable. For this case you can find lots of tutorials on how to flash Arduino boards with a second Arduino. I didn’t have a second Arduino at the time though … so why not just bit-bang it from a Raspberry Pi instead?

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Managing containers with podman and systemd

tl;dr: Use simple systemd units to supervise your containers.

A while ago I stumbled upon podman, which touts itself as an alternative to Docker. Not only does podman not use any big fat daemons™ but it makes it rather easy to run containers in a user-namespace, i.e. with greatly restricted privileges on your system. The fun thing is: you are still root within the container!

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Commit hash replacement in Git archives

tl;dr: use $Format:%h$ in a file and mark for substitution in downloaded archives with 'file export-subst' in .gitattributes

Trying to implement some sort of automatic versioning based on your git commits or tags is not as easy as it should seem. The idea is to use a feature built into the revision control system to modify your project files and increment version counters automatically or embed commit information into software builds - in my case: the --version output of Go applications built with cobra. Ideally, the solution should not require executing some hacked-together scripts or configuring overly many settings on developer machines, yet still embed version information when a user donwloads a release to build locally. read on »

Speedtest Plotter

tl;dr: running speedtest-cli with a cronjob and plotting the results

I am supposed to have a 500 Mbps internet line at home. Last week it really didn’t feel like that (again). Pages would take ages to load, streams would stutter miserably or simply abort and downloading OS updates simply timed out. So I set out to measure my actual bandwidth over a longer period of time.

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Set up 2FA app for PayPal

tl;dr: the option to add TOTP security keys on PayPal is somewhat hidden, it uses Verisign Identity Protection provisioning

It is becoming common knowledge that you should use two-factor authentication whenever possible. Some services allow the use of TOTP apps on your smartphone, some only want so send you SMS codes .. and others use proprietary tokens.

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