#!/usr/bin/env bash

if [[ "" == "$@" ]]; then
    echo "usage: $0 <file(s) to convert>"
    exit 1
fi

for i in "$@"; do
    directory=$(realpath $(dirname "$i"))
    file=$(basename "$i")
    name=${file%.*}
    extension=$(echo ${file##*.} | tr '[:upper:]' '[:lower:]')

    if [[ "$extension" == "psd" ]]; then
        target="$directory/$name.png"
        if [[ -e "$target" ]]; then
            echo "file already exists: '$target'"
        else
            echo "converting '$i'"
            convert "$i" -background none -flatten "$target" || exit 1
        fi
    fi
done

This takes the file(s) to convert as argument(s). You can also just go with wildcards like *.psd to convert all psd files in a folder. Already converted files will be skipped.

You need ImageMagic installed on your machine to have access to the convert command.

Tested with ImageMagic 7.1.1-27 on MacOS Sonoma 14.3.1.

sudo dpkg-divert --divert /etc/apt/apt.conf.d/20apt-esm-hook.conf.bak --rename --local /etc/apt/apt.conf.d/20apt-esm-hook.conf

This will add .bak to the end of the file and should survive updates.

This example would create an amd64 and a aarch64 (arm64/v8) image:

# ARM
docker build --platform=linux/aarch64 -t <dockerhub-username>/<image-name>:<version>-aarch64 .
docker push -t <dockerhub-username>/<image-name>:<version>-aarch64

# AMD
docker build --platform=linux/amd64 -t <dockerhub-username>/<image-name>:<version>-amd64 .
docker push -t <dockerhub-username>/<image-name>:<version>-amd64

Based on these you can create a manifest and upload it:

docker manifest create <dockerhub-username>/<image-name>:<version> \
  --amend <dockerhub-username>/<image-name>:<version>-aarch64 \
  --amend <dockerhub-username>/<image-name>:<version>-amd64
docker manifest push <dockerhub-username>/<image-name>:<version>

This would already provide an image <dockerhub-username>/<image-name>:<version> available for amd64 and aarch64 platform on docker hub. But for convenience we also want a latest tag for that manifest:

docker manifest create <dockerhub-username>/<image-name>:latest \
  --amend <dockerhub-username>/<image-name>:<version>-aarch64 \
  --amend <dockerhub-username>/<image-name>:<version>-amd64
docker manifest push <dockerhub-username>/<image-name>:latest

This uses the same hashes as the version uploaded before.

I am not sure if this is the correct or best way, but at least it works. On my M1 mac buildx didn’t work so I fell back to manifests that aren’t that complicated anyway.

Here an example image that was created and uploaded like this: https://registry.hub.docker.com/r/mbopm/cyberchef.

This approach is a very cheap way to get proper time code into cameras. If your device – like my notebook – has a built in microphone you could for example do the same as tentacle sync e and record time code on one and micro input on the other stereo channel of your for example digital camera. Of course syncing devices via ntp isn’t as accurate as syncing explicitly and having extra hardware for time code generation but this way I can use existing hardware instead of buying devices for hundreds of euros that aren’t shippable for weeks or months, cost a fortune and I don’t use very often.

In the following my notes about how to use ltc-tools and jack for time code generation.

First you need to install the dependencies:

brew install jack
brew install ltc-tools

With these in place you first have to start the jack daemon:

jackd --realtime -dcoreaudio

Then connect the time code generator with your desired frame rate

jltcgen -f 25

This now sends time code to jack input. On my system this input is named genltc:ltc. You can display all ports usable in jack via

jack_lsp

On my machine this gives the following output:

system:capture_1
system:playback_1
system:playback_2
genltc:ltc

capture_1 is my mic, playback_1 the left and playback_2 the right speaker.

To connect the time code generator with my left speaker (and immediately disconnect it again because of the annoying sound) the commands are:

# output time code on left and mic on right channel
jack_connect genltc:ltc system:playback_1
jack_connect system:capture_1 system:playback_2

# disconnect it again
jack_disconnect genltc:ltc system:playback_1
jack_disconnect system:capture_1 system:playback_2

If you don’t disconnect it your device should make some weird sound which is the time code. In case you connect the mic like in my sample make sure to use headphones otherwise you will create a feedback loop.

sed -i -z 's/^\n*\|\n*$//g' file.txt

Here a summary of commands if you have everything installed and want to bring up minikube with openfaas:

minikube start
arkade install openfaas

# wait until the following command shows all services as ready:
kubectl -n openfaas get deployments -l "release=openfaas, app=openfaas"

kubectl rollout status -n openfaas deploy/gateway
kubectl port-forward -n openfaas svc/gateway 8080:8080 &

PASSWORD=$(kubectl get secret -n openfaas basic-auth -o jsonpath="{.data.basic-auth-password}" | base64 --decode; echo)
echo -n $PASSWORD | faas-cli login --username admin --password-stdin

# check if the service answers:
faas-cli list

# print password
echo $PASSWORD

After this you can open http://localhost:8080 with admin user and above printed password.

brew install gnu-sed

This installs the program as gsed which is also not handy if you don’t want to write different scripts for Linux and macOS. If you want to get rid of macOS’s sed then you need to add the following line to your .zshrc file and restart your terminal or source the config:

PATH="$(brew --prefix)/opt/gnu-sed/libexec/gnubin:$PATH"

This adds gnu programs in front of macOS’s programs and whatever gnu tools you’re installing via brew are then replacing the existing versions.

I installed virtualbox and set up a vm with shared host adapter for being able to easily access it via ip. On that ubuntu vm which I access from outside via SSH I installed docker as documented on the official docker documentation and gave my user proper rights to use docker. The vm has proper internet access and can run docker containers with ports mapped to the shared host adapter.

From my mac I installed docker via brew (not desktop) and added a context for the vm:

docker context create vm --description "local ubuntu vm" --docker "host=ssh://manuel@ubuntu"

The “ubuntu” hostname was added to my /etc/hosts with the configured ip of the vm and manuel is my ssh user on the vm.

With the new context created the context list looks like this:

➜  ~ docker context ls
NAME                TYPE                DESCRIPTION                               DOCKER ENDPOINT                                KUBERNETES ENDPOINT   ORCHESTRATOR
default *           moby                Current DOCKER_HOST based configuration   unix:///var/run/docker.sock                                          swarm
desktop-linux       moby                                                          unix:///Users/manuel/.docker/run/docker.sock                         
vm                  moby                local ubuntu vm                           ssh://manuel@ubuntu

After switching the context to `vm` I can easily work with docker running on the vm.

docker context use vm

With the use of context I was able to come around docker-desktop completely. So the argument that docker isn’t usable anymore on a non linux machine is busted.

First take down all services that depend on the database by using systemctl and also bring down the two pg instances:

user@~$ sudo systemctl stop postgresql@13-main
user@~$ sudo systemctl stop postgresql@14-main

Then check the clusters you have:

user@~$ sudo su - postgres
postgres@~$ pg_lsclusters
Ver Cluster Port Status Owner    Data directory              Log file
13  main    5432 online postgres /var/lib/postgresql/13/main /var/log/postgresql/postgresql-13-main.log

If you see a new cluster for 14 already check that it’s empty and remove it if so by

postgres@~$ pg_dropcluster --stop 14 main

Then upgrade your existing cluster and bring the new server up again

postgres@~$ pg_upgradecluster 13 main
postgres@~$ exit
user@~$ sudo systemctl stop postgresql@14-main

After this bring your dependent services up and test them. After verifying you can drop the old cluster:

user@~$ sudo su - postgres
postgres@~$ pg_dropcluster --stop 13 main

This should be it. To get rid of the old version you can also run

user@~$ sudo apt purge postgresql-13 postgresql-client-13

The described process worked well for me but be warned that this has potential to delete all your databases. So be careful. Just to be sure I want to state here that I don’t take any responsibility for your data loss or the resulting problems of it ;-) Having backups before starting this process would be a good idea!

# overwrite partition tables
dd if=/dev/zero of=/dev/sdc bs=512 count=1024
dd if=/dev/zero of=/dev/sdd bs=512 count=1024
# create btrfs with single drive first
mkfs.btrfs -m single /dev/sdc

# get uuid and add it to fstab for automount
blkid | grep sdc
# => /dev/sdc: UUID="cc3a8b12-5b75-4c71-b5a7-ad151b69eb22" ...
echo "UUID=cc3a8b12-5b75-4c71-b5a7-ad151b69eb22 /data btrfs defaults,autodefrag 0	0" >> /etc/fstab
mount -a

# add second disk
btrfs device add /dev/sdd /data
# and change the fs to raid1
btrfs balance start -dconvert=raid1 -mconvert=raid1 /data

This was already working properly and I was able to copy my data on the newly created raid. I added the following to my /etc/hdparm.conf to turn off the disks when not needed:

# see hdparm -S
# 120 * 5sec = 600sec
# 600sec / 60sec = 10min
# frequent spin downs will damage a disk so i chose 20min!!

/dev/sdc {
	spindown_time = 240
}

/dev/sdd {
        spindown_time = 240
}

Haven’t tested everything yet, but works as expected until now =)