About a decade ago I was playing a game on Linux and the game crashed and took the entire DE with it. So I went to a different tty and started a fresh x desktop session and started playing again until the game crashed again (I was running a bunch of mods so it would crash every couple of hours or so) and still didn’t feel like rebooting so I went to yet another tty and started yet another x desktop session. I did this about 3 times in total before I finally went “I should probably actually reboot because this has to be making a bigger mess of things”

I got an Orange Pi 5 Plus to play with smallish AIs (because it has an NPU) and I normally access it remotely, so I have to know its IP address to do it.

In order to easilly know the IP address of it, I’ve wired a little 128x64 monochrome OLED screen to it (Orange PIs, like Raspberry PIs have a pin connector giving access to GPIO and interfaces like I2C, Serial and SPI) which talks via I2C.

Turns out those interfactes aren’t active in Linux by default (I.e. no /dev/i2c-x), so I figured out that I had to add a kernel overlay to activate that specific interface (unlike with the Raspberry PI whose Linux version has a neat program for doing it, in the Orange Pi you have to know how the low level details of activating those things), which I did.

To actually render characters on that screen I went with an ARM Linux port of a graphics library for those screens I used before with Arduino, called u8g2)

Then I made a program in C that just scans all network interfaces and prints their names and IP addresses on that screen, and installed it as a Cron job running once a minute.

Now, as it turns out when you shutdown your Linux on that board, if you don’t disconnect it from power there is actually still power flowing through the pin connector to any devices you wire there, so after shutdown my screen would remain ON and showing the last thing I had put there, but because the OS was down it would naturally not get updated.

So the last thing I did was another small C program which just sends to that screen the command for it to go into power saving mode, shutting it down. This program was then installed as a Systemd Service to run when Linux is shutting down.

The result is now that there is a little screen hanging from the box were I put this board with Linux which lists its IP addresses and the info is updated if it connects other interfaces or reconnects and gets a new IP address. Curiously I’ve actually been using that feature because it’s genuinely useful, not just a funny little project.

Side of the case fell off.

My control key was broken, but I found that when I used an app and held down the space bar key, the CPU would get abnormally hot.

So I wrote an Emacs interrupt to interpret a rapid CPU rise as “press the control button”.

Unfortunately the dev pushed an update that broke space bar heating, which broke my workflow. I opened a bug report about it, though…

I have a Logitech mouse with extra buttons, I used Piper to set one of those buttons to be Play/Pause media button. It worked well, however for some reason it only worked when the mouse was connected via the dongle, via Bluetooth the button did nothing. So I configured to a random shortcut (don’t remember what it is now, something like super+p) and configured that to call playctl play/pause.

Not as creative or duct tapey as others but it’s what I remember now, pretty sure there are many others too hahaha

I like to use unclutter to hide my mouse pointer after a few seconds without being moved.

Now, the thing is, it doesn’t just visually hide the cursor, it actually removes it, so UI elements triggered by hovering disappear. Sometimes that’s great, other times it’s infurriating, like when reading a tooltip or menu.

I mostly use a touchpad, and so I developed a habit to wiggle my finger while I’m intentionally hovering something, so that there was enough mouse movement for unclutter to not remove my pointer.

Then I found a setting for the jitter threshold of the touchpad. Basically, with the threshold on, it ignores tiny movements, because the hardware reports finger wiggling, even if you hold your finger perfectly still. Which is perfect for me to turn off.

Now when I have my finger on the touchpad, it automatically wiggles and allows me to read hover elements. If I take my finger off, it stops wiggling and removes the cursor.
It’s almost like someone designed an OS with touchpads in mind, rather than them being an afterthought.

intel won’t allow its linux drivers to work above wifi 4 speeds in ap mode, so i created a kvm virtual windows machine with pci pass through on the wifi nic plus ip masquerade and now i’m getting wifi 6 speeds in ap mode.

I think this one beats them all.

My home server keeps a few services up, including an instance of Jitsi Meet. The server runs nixos and the nixos package for jitsi is incomplete to say the least and doesn’t even support authentication, so I use the docker-compose version and I have a script that runs periodically to keep it updated. So far so good, right? Well, no.

Because the server is at home, I have a dynamic external IP address, so I have to use a DDNS provider, but jitsi doesn’t expect this and uses a stun server at startup to determine the public IP of the server once, so if my connection goes down or is restarted and the IP changes, jitsi needs to be restarted or it won’t work anymore.

The solution?

• My router runs OpenWrt, so I am able to run a script that checks for external IP changes. When a change is detected, it uses SSH to connect to my server to restart jitsi
• Because I don’t want the router to just be able to run any command, I created a jitsi-restart user that has no shell
• When the router tries to log in with its pubkey, sshd creates a file called restartasap in the jitsi folder and closes the connection
• On the server, there’s a systemd unit running a script as the jitsi user that periodically checks for that file, and if it exists it deletes it and restarts jitsi

I’ve been running this setup since mid 2020 and I expect this to continue until IPv6 becomes the norm.

holy shit i was about to post about how i have automatic login and lock to start a program that refuses to work correctly on boot through systemd.

but then you guys are here casually posting some of the worst duct tape shit ive heard of so far. im not sure if i should reprimand or congratulate you for that jankiness.

I duct taped a Raspberry Pi to the back of a television once. Does that count?

I’m using Gentoo with systemd and a customized kernel, and additionally I have the /usr partition LUKS encrypted. Because /usr is absolutely essential for systemd to function, I configured dracut to make a specially crafted initrd which activates the luks lvm and prompts for the password to decrypt and mount /usr on startup before systemd init tries to run.

About a year or two ago, some update to dracut or some other dependency (assumption) caused the dracut generated initrd’s to kernel panic. After multiple days of troubleshooting, I discovered that just copying forward an older initrd in /boot and naming it to match the new kernel, e.g. initramfs-6.6.38-gentoo.img , allows the system to boot normally .

So, my Gentoo is booting a kernel 6.6.something with a ramdisk generated in the 5.9 kernel era. I am dreading the day when this behavior breaks and I can no longer update my kernel 😳

An old (now decommissioned) notebook of mine had a broken headphone jack. I didn’t have BT headphones then. Audio output worked technically but the detection whether headphones were plugged in or not did no longer work.

I wrote a very short amixer script to force unmute the jack, set the volume to 50 or so percent and set the speaker volume to 0% but not “mute” state. I could then use my wired headphones again.

Some years ago, I had a client with a really fucked up set of requirements:

• Must run Gentoo Linux. (No, I don’t know why. But it was written into the project specs and everybody who had to sign off did.)
• Must use LUKS for FDE.
• Login (loosely interpreted as “booting up”) must have MFA.

This was during the days when booting into a LUKS encrypted Gentoo install involved copy-and-pasting a shell script out of the Gentoo wiki and adding it to the initrd. I want to say late 2006 or early 2007.

I remember creating a /boot partition, a tiny little LUKS partition (512 megs, at most) after it, and the rest of the drive was the LUKS encrypted root partition. The encrypted root partition had a randomly generated keyfile as its unlocker; it was symmetrically encrypted using gnupg and a passphrase before being stored in the tiny partition. The tiny partition had a passphrase to unlock it. gnupg was in the initrd. I think the workflow went something like this:

• System boots up.
• Script in the initrd prompted the user for the passphrase for the tiny LUKS partition. (first authentication step)
• User entered passphrase.
• Script in the initrd unlocked the tiny partition and prompted the user for the passphrase to decrypt the root partition’s keyfile stored therein.
• User entered the symmetric passphrase for keyfile. (second authentication step_
• Script used the passphrase to decrypt the keyfile to stdout, piped into an evocation of cryptsetup to unlock the root partition.
• /dev/mapper/root mounted, /boot mounted, boot process continued.
• User logged into the box.

I don’t miss those days.

I had an external hard drive enclosure that I stored my Plex content on before I built a nas, and the enclosure would go to sleep after 15 minutes and take the drives offline. So i had a cron script write a 1 kb file to each drive every 14 minutes. Worked well enough

On my previous laptop, the trackpad had a bug that made it spam interrupts after waking up from sleep. It ruined battery life and basically kept one core at 100% permanently.

So I duct-taped a systemd script that unbound and bound the trackpad after each wake up.

#!/bin/sh
case "$1" in
        post)
                echo -n "i2c_designware.0" > /sys/bus/platform/drivers/i2c_designware/unbind
                echo -n "i2c_designware.0" > /sys/bus/platform/drivers/i2c_designware/bind
        ;;
esac