### Setup Distrobox for KDE development

Source: https://linux.kde.org/docs/kde-dev

Creates and configures a containerized environment for building KDE software.

```bash
# As per https://develop.kde.org/docs/getting-started/building/containers-distrobox
distrobox create --image docker.io/archlinux --name kdebuildercontainer --home ~/kdebuildercontainer_home
distrobox enter kdebuildercontainer
run0 pacman -Syu
run0 pacman -S nano
echo 'export PATH="$HOME/.local/bin:$PATH"' | tee --append ~/.{bash,zsh}rc
exit
distrobox enter kdebuildercontainer

# Install kde-builder as usual. https://develop.kde.org/docs/getting-started/building/kde-builder-setup
```

--------------------------------

### Initialize Systemd Extension

Source: https://linux.kde.org/docs/override-usr

Executes the setup script required to prepare the systemd extension environment.

```bash
set-up-systemd-extension
```

--------------------------------

### Install Virtual Machine Manager via Flatpak

Source: https://linux.kde.org/docs/vm

Installs the Virtual Machine Manager application and the necessary QEMU extension.

```bash
flatpak install org.virt_manager.virt-manager org.virt_manager.virt_manager.Extension.Qemu
```

--------------------------------

### Setup systemd-sysext development environment

Source: https://linux.kde.org/docs/kde-dev

Initializes the system development environment for base image modifications.

```bash
set-up-system-development
```

--------------------------------

### Install Nix for current user

Source: https://linux.kde.org/docs/nix

Executes the Nix installation script for a single-user system without requiring daemon privileges.

```bash
sh <(curl --proto '=https' --tlsv1.2 -L https://nixos.org/nix/install) --no-daemon
```

--------------------------------

### Install package with nix-env

Source: https://linux.kde.org/docs/nix

Installs a package persistently to the user's environment using the legacy nix-env command.

```bash
$ nix-env -f '' -iA mc
⋮
building '/nix/store/1q2sh2f178jx9fl37gd9ks85ysfvpwd9-user-environment.drv'...
```

--------------------------------

### Install Flatpak debug packages

Source: https://linux.kde.org/docs/flatpak-crashes

Installs the SDK and debug symbols for a specific Flatpak application ID.

```bash
flatpak install --include-sdk --include-debug [app id]
```

--------------------------------

### Configure QEMU for UEFI Boot

Source: https://linux.kde.org/docs/install-vm

Set up a QEMU virtual machine with OVMF firmware and a virtual disk for installation.

```bash
cp /usr/share/edk2/x64/OVMF_VARS.4m.fd ./OVMF_VARS.4m.fd
qemu-img create -f qcow2 kde-linux.qcow2 20G

qemu-system-x86_64 -enable-kvm -m 4G -smp 4 \
  -drive if=pflash,format=raw,readonly=on,file=/usr/share/edk2/x64/OVMF_CODE.4m.fd \
  -drive if=pflash,format=raw,file=./OVMF_VARS.4m.fd \
  -drive file=kde-linux.qcow2,if=virtio \
  -cdrom kde-linux.iso
```

--------------------------------

### Create and manage a Distrobox container

Source: https://linux.kde.org/docs/more-software

Commands to initialize, enter, and install software within a Distrobox container.

```bash
# Try to run a command, for example "mc"
mc

# It does not work because is not installed on the system
# KDE Linux does not include the “mc” command.

# Download the image "quay.io/toolbx/arch-toolbox".
distrobox create -n default

# Enter it
distrobox enter default

# Do whatever you want in it. Here, we install `mc`
run0 pacman -Syu
run0 pacman -S mc

# Run `mc`. Your home directory from KDE Linux is exposed as your home directory inside the Linux container. Press F10 to close mc.
mc

# Exit the distrobox container
```

```bash
# To find the container image:
podman image list

# To see the distrobox podman container still running:
podman ps
distrobox list
distrobox stop default

# To delete the container:
distrobox rm name
podman image list # Says "IMAGE ID" is 664c1f5776fa.
podman image rm 664c1f5776fa
podman image list
```

--------------------------------

### Verify package installation

Source: https://linux.kde.org/docs/nix

Checks the location of an installed binary to confirm it is in the user's search path.

```bash
$ which mc
/home/username/.nix-profile/bin/mc
```

--------------------------------

### Install DaVinci Resolve on Non-NVIDIA GPU

Source: https://linux.kde.org/docs/more-software

Downloads and executes the setup script for DaVinci Resolve on systems without NVIDIA hardware.

```bash
wget https://raw.githubusercontent.com/zelikos/davincibox/refs/heads/main/setup.sh --directory-prefix=/tmp/
chmod +x /tmp/setup.sh
/tmp/setup.sh [drag the .run file into the terminal window, or paste its path here]

```

--------------------------------

### Install kernel modules and image into sysext

Source: https://linux.kde.org/docs/kernel-dev

Installs compiled modules and the kernel image into the systemd system extension overlay.

```bash
make INSTALL_MOD_PATH="$HOME/kde/usr" modules_install
```

```bash
version=$(make -s kernelrelease)
install -Dm644 "$(make -s image_name)" \
  "$HOME/kde/usr/lib/modules/$version/vmlinuz"
```

```bash
run0 systemd-sysext refresh --always-refresh=yes
```

--------------------------------

### Configure and use nix profile

Source: https://linux.kde.org/docs/nix

Enables experimental features and installs a package using the modern nix profile interface.

```bash
$ mkdir -p ~/.config/nix
$ cat >> ~/.config/nix/nix.conf <<EOF
experimental-features = nix-command flakes
EOF

$ nix search nixpkgs silver searcher
⋮
* legacyPackages.x86_64-linux.silver-searcher (2.2.0)
  Code-searching tool similar to ack, but faster

$ nix profile add nixpkgs#silver-searcher
$ which ag
/home/username/.nix-profile/bin/ag
```

--------------------------------

### Install the Unified Kernel Image

Source: https://linux.kde.org/docs/kernel-dev

Copies the generated UKI to the EFI System Partition for bootloader recognition.

```bash
run0 cp kde-linux.efi /boot/EFI/Linux/
```

--------------------------------

### Update system from 2024-12-01 image or earlier

Source: https://linux.kde.org/docs/migrate-older

Use these commands to update systems installed from the 2024-12-01 image or older.

```bash
git clone https://invent.kde.org/kde-linux/kde-linux
cd kde-linux
run0 ./update.sh update
```

--------------------------------

### Manage packages with nix profile

Source: https://linux.kde.org/docs/nix

Lists installed packages or removes them using the nix profile command.

```bash
$ nix profile list
⋮
Name:               silver-searcher
Flake attribute:    legacyPackages.x86_64-linux.silver-searcher
Original flake URL: flake:nixpkgs
Locked flake URL:   github:NixOS/nixpkgs/f08e6b11a5ed43637a8ac444dd44118bc7d273b9?narHash=sha256-7vUo0qWCl/rip%2Bfzr6lcMlz9I0tN/8m7d5Bla/rS2kk%3D
Store paths:        /nix/store/l120si3zsshmf3jr7dkn5dvcj0n586xb-silver-searcher-2.2.0

$ nix profile remove silver-searcher
```

--------------------------------

### Uninstall package with nix-env

Source: https://linux.kde.org/docs/nix

Removes a previously installed package from the user's environment.

```bash
$ nix-env -e mc
uninstalling 'mc-4.8.33'
building '/nix/store/rqbghiyds6f7a49qiwi9gmq7bnkgn9qi-user-environment.drv'...
```

--------------------------------

### Install DaVinci Resolve on NVIDIA GPU

Source: https://linux.kde.org/docs/more-software

Uses Distrobox to create a containerized environment for DaVinci Resolve on systems with NVIDIA hardware.

```bash
distrobox create -i ghcr.io/zelikos/davincibox:latest --nvidia -n davincibox
[drag the .run file into the terminal window, or paste its path here] --appimage-extract
distrobox enter davincibox -- run0 dnf update

```

--------------------------------

### Identify Nix profile incompatibility error

Source: https://linux.kde.org/docs/nix

Example of the error message encountered when experimental profile features conflict with nix-env.

```text
error: profile '/home/username/.local/state/nix/profiles/profile' is incompatible with 'nix-env'; please use 'nix profile' instead
```

--------------------------------

### Clean up built files

Source: https://linux.kde.org/docs/kde-dev

Removes files installed by the build process. Answer 'n' when prompted for the extension-release.kde file.

```bash
rm -r ~/kde/usr/*
# When you’re prompted to delete the read-only extension-release.kde file, answer 'n'
```

--------------------------------

### Create the boot loader addons directory

Source: https://linux.kde.org/docs/kernel-cmdline

Initializes the directory required for storing kernel add-on files.

```bash
run0 mkdir -p /boot/loader/addons/
```

--------------------------------

### Configure the kernel

Source: https://linux.kde.org/docs/kernel-dev

Sets up the build configuration using default settings or interactive configuration tools.

```bash
make defconfig
```

```bash
make menuconfig
make nconfig
make xconfig
```

--------------------------------

### Build KDE app with Flatpak

Source: https://linux.kde.org/docs/kde-dev

Clones source code and builds an application using flatpak-builder.

```bash
# Create folder to hold KDE source code. Skippable if it already exists
mkdir -p ~/kde/src/

# Go into that folder
cd ~/kde/src/

# Download source code for Filelight
git clone git@invent.kde.org:utilities/filelight.git

# Go into Filelight’s source code folder
cd ~/kde/src/filelight

# Build Filelight as a flatpak
flatpak-builder build --user --install-deps-from=flathub-apps-built-locally --force-clean --ccache --install .flatpak-manifest.json
```

--------------------------------

### Compile and apply system changes

Source: https://linux.kde.org/docs/kde-dev

Builds a specific component, refreshes the system extension, and restarts the relevant user service.

```bash
kde-builder plasma-pa
run0 systemd-sysext refresh --always-refresh=yes
systemctl restart --user plasma-plasmashell.service
```

--------------------------------

### Create Btrfs volume for Docker

Source: https://linux.kde.org/docs/kde-linux-dev

Commands to set up a Btrfs volume backed by a file if the host filesystem is not Btrfs.

```bash
systemctl stop docker.socket docker.service || true
fallocate -l 64G /store/docker.btrfs
mkfs.btrfs /store/docker.btrfs
[ -d /var/lib/docker ] || mkdir /var/lib/docker
mount /store/docker.btrfs /var/lib/docker
systemctl restart docker.socket docker.service
```

--------------------------------

### Configure local build speed with mkosi

Source: https://linux.kde.org/docs/kde-linux-dev

Create a mkosi.local.conf file in the repository root to optimize build performance.

```ini
[Content]
Environment=LOCALE_GEN="en_US.UTF-8 UTF-8" # replace with your locale`
Environment=MIRRORS_COUNTRY=us # replace with your country code`
Environment=PARALLEL_DOWNLOADS=50 # if your internet connection is fast
```

--------------------------------

### Run standard Docker build

Source: https://linux.kde.org/docs/kde-linux-dev

Execute the build script to generate a custom system image.

```bash
./build_docker.sh
```

--------------------------------

### Verify and Test Systemd Extension

Source: https://linux.kde.org/docs/override-usr

Commands to confirm the extension is active, create a test file, refresh the system state, and verify the override.

```bash
# Verify that it got enabled
systemd-sysext

# Create a dummy file in the sysext
echo "It worked" > ~/kde/usr/foo

# Refresh the sysext so the system sees the change
run0 systemd-sysext refresh --always-refresh=yes

# Make sure it appeared in /usr as expected
cat /usr/foo
```

--------------------------------

### Build the kernel

Source: https://linux.kde.org/docs/kernel-dev

Compiles the kernel image and modules using the standard build system.

```bash
make -j$(nproc)
```

--------------------------------

### Run built Flatpak application

Source: https://linux.kde.org/docs/kde-dev

Executes the locally built Flatpak application.

```bash
org.kde.filelight
```

--------------------------------

### Configure Steam Games for Dedicated GPU

Source: https://linux.kde.org/docs/multi-gpu

Set these launch options in Steam properties to force games to use a dedicated graphics card.

```bash
DRI_PRIME=1 %command%
```

```bash
__NV_PRIME_RENDER_OFFLOAD=1 __VK_LAYER_NV_optimus=NVIDIA_only __GLX_VENDOR_LIBRARY_NAME=nvidia %command%
```

--------------------------------

### Launch temporary Nix shell

Source: https://linux.kde.org/docs/nix

Opens a shell session with specified packages available in the search path temporarily.

```bash
nix-shell -p mc emacs-nox  # you are now inside a shell with mc and emacs
```

--------------------------------

### Apply system update for erofs migration

Source: https://linux.kde.org/docs/migrate-older

Run this command after creating the enable.conf file to finalize the migration to an erofs volume.

```bash
run0 /usr/lib/systemd/systemd-sysupdate update
```

--------------------------------

### Manage Python virtual environments

Source: https://linux.kde.org/docs/python-dev

Commands to create, activate, populate, and remove a virtual environment for local Python development.

```bash
# Create a new virtual environment in the current directory named “venv”
python -m venv venv

# Activate the “venv” virtual environment
source venv/bin/activate

# Install what you need
python -m ensurepip --default-pip
pip install [whatever Python modules you need]

# run or develop the tool

# Exit the virtual environment
deactivate

# Optional: delete the “venv” virtual environment if you don’t need it anymore
rm -r venv
```

--------------------------------

### Report boot failure logs

Source: https://linux.kde.org/docs/boot-failure-recovery

Command to retrieve logs from the previous boot for troubleshooting purposes.

```bash
journalctl --boot -1 --no-pager
```

--------------------------------

### Enter emergency root shell

Source: https://linux.kde.org/docs/boot-failure-recovery

Add these parameters to the kernel command line to enable the emergency root shell.

```text
systemd.debug_shell=on SYSTEMD_SULOGIN_FORCE=1
```

--------------------------------

### Build a kernel add-on

Source: https://linux.kde.org/docs/kernel-cmdline

Generates an EFI add-on file containing the specified kernel command-line arguments.

```bash
run0 ukify build --cmdline '[arguments go here]' --output /boot/loader/addons/extra_args.addon.efi
```

--------------------------------

### Connect via SSH

Source: https://linux.kde.org/docs/remote-login

Command syntax for initiating an SSH connection to a remote system.

```bash
ssh [username of a user on the other system]@[IP address of the other system]
```

```bash
ssh alex@192.168.1.1
```

--------------------------------

### List Compose Key Sequences

Source: https://linux.kde.org/docs/char-input

Displays the available Compose key sequences by filtering the system locale configuration file.

```bash
rg Multi_key /usr/share/X11/locale/en_US.UTF-8/Compose | cut -d "\"" -f 1,2
```

--------------------------------

### Enable EFI in VirtualBox via CLI

Source: https://linux.kde.org/docs/install-vm

Use this command to enable EFI firmware for an existing VirtualBox VM from the terminal.

```bash
VBoxManage modifyvm "<vm-name>" --firmware efi
```

--------------------------------

### Launch Applications with Dedicated GPU via Terminal

Source: https://linux.kde.org/docs/multi-gpu

Run these commands in a terminal to temporarily launch an application using the dedicated GPU.

```bash
DRI_PRIME=1 [the executable name/path of the app]
```

```bash
prime-run [the executable name/path of the app]
```

--------------------------------

### Enable erofs-based /usr feature

Source: https://linux.kde.org/docs/migrate-older

Create this configuration file after updating to the 2025-08-05 image or later to enable the erofs-based /usr feature.

```ini
[Feature]
Enabled=true
```

--------------------------------

### Run incremental Docker build

Source: https://linux.kde.org/docs/kde-linux-dev

Execute the build script with the incremental flag.

```bash
./build_docker.sh --incremental
```

--------------------------------

### Configure Docker storage driver

Source: https://linux.kde.org/docs/kde-linux-dev

Set the storage driver to Btrfs in the Docker daemon configuration.

```json
{
  "storage-driver": "btrfs"
}
```

--------------------------------

### Blacklist NVIDIA drivers

Source: https://linux.kde.org/docs/pre-turing-nvidia

Create this configuration file to ensure the system uses the Nouveau driver instead of proprietary NVIDIA drivers.

```bash
install nouveau
blacklist nvidia
```

--------------------------------

### Enable and Verify SSH Service

Source: https://linux.kde.org/docs/remote-login

Commands to enable the SSH daemon and check its current status.

```bash
systemctl enable --now sshd
```

```bash
systemctl status sshd
```

--------------------------------

### Add Flathub remote for Flatpak builds

Source: https://linux.kde.org/docs/kde-dev

Configures the local Flatpak environment to pull dependencies from the official Flathub store.

```bash
flatpak remote-add --user --if-not-exists flathub-apps-built-locally https://flathub.org/repo/flathub.flatpakrepo
```

--------------------------------

### Clone the Linux kernel repository

Source: https://linux.kde.org/docs/kernel-dev

Initializes the local kernel source tree using the upstream Git repository.

```bash
git clone https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
cd linux
```

--------------------------------

### Garbage collect Nix store

Source: https://linux.kde.org/docs/nix

Commands to remove unreachable packages and reclaim disk space from the Nix store.

```bash
nix-store --gc           # routine garbage collection
nix-collect-garbage -d   # remove "unreachable" packages from the store
```

--------------------------------

### Restore /etc directory

Source: https://linux.kde.org/docs/boot-failure-recovery

Commands to rename a broken /etc directory and restore a previous snapshot.

```bash
run0 mv /etc /etc.broken
run0 btrfs subvolume snapshot $(ls -d -1 /.etc.* | tail -2 | head -1) /etc
systemctl reboot
```

--------------------------------

### Retrieve System IP Address

Source: https://linux.kde.org/docs/remote-login

Command to list network interfaces and identify the system's IP address.

```bash
ip address
```

--------------------------------

### Bypass login screen or Plasma

Source: https://linux.kde.org/docs/boot-failure-recovery

Add this parameter to the kernel command line to boot into a multi-user target, bypassing graphical environments.

```text
systemd.unit=multi-user.target
```

--------------------------------

### Disable system extension

Source: https://linux.kde.org/docs/kde-dev

Unmerges the current system extension to revert changes.

```bash
run0 systemd-sysext unmerge
```

--------------------------------

### Disable experimental features and clear profile state

Source: https://linux.kde.org/docs/nix

Commands to comment out experimental features in the configuration and remove the profile state directory.

```bash
$ sed -i'' 's/^experimental-features = nix-command flakes$/#&/' ~/.config/nix/nix.conf
$ rm -rf ~/.local/state/nix/profiles/profile
```

--------------------------------

### Rebuild EFI images

Source: https://linux.kde.org/docs/kernel-dev

Generates a new Unified Kernel Image (UKI) after updating the sysext contents.

```bash
run0 /usr/lib/rebuild-efi
```

--------------------------------

### Generate a Flatpak crash backtrace

Source: https://linux.kde.org/docs/flatpak-crashes

Uses the flatpak-coredumpctl utility to retrieve crash information for a specific application.

```bash
flatpak-coredumpctl [app id]
```

--------------------------------

### Grant global low-latency privileges to a user

Source: https://linux.kde.org/docs/low-latency

Adds the current user to the realtime group to enable low-latency privileges for all processes. Use with caution as this is a significant system change.

```bash
run0 useradd -G realtime -m $(whoami)
```

--------------------------------

### Remove Nix package manager

Source: https://linux.kde.org/docs/nix

Commands to stop the daemon, delete system files, and remove build users and groups.

```bash
run0 systemctl disable --now nix-daemon.service nix-daemon.socket

run0 rm -rf /nix /etc/nix /etc/profile.d/nix.sh /etc/tmpfiles.d/nix-daemon.conf /nix /root/.nix-channels /root/.nix-defexpr /root/.nix-profile /root/.cache/nix ~/.nix-channels ~/.nix-defexpr ~/.nix-profile ~/.cache/nix

for i in $(seq 1 32); do run0 userdel nixbld$i; done

run0 groupdel nixbld
```

--------------------------------

### Disable systemd extensions via kernel command line

Source: https://linux.kde.org/docs/boot-failure-recovery

Add this parameter to the kernel command line to temporarily disable systemd extensions.

```text
systemd.mask=systemd-sysext.service
```

--------------------------------

### Add ssh-add to shell configuration

Source: https://linux.kde.org/docs/ssh-keys

Include this command in your ~/.zshrc or ~/.bashrc file to automatically unlock SSH keys in new terminal sessions.

```bash
ssh-add
```

--------------------------------

### Remove a kernel add-on

Source: https://linux.kde.org/docs/kernel-cmdline

Deletes the add-on file to stop applying the custom kernel arguments.

```bash
run0 rm /boot/loader/addons/extra_args.addon.efi
```

--------------------------------

### Disable systemd SSH agent service

Source: https://linux.kde.org/docs/ssh-keys

Use this command to mask the systemd SSH agent service if you prefer to manage SSH keys manually.

```bash
systemctl mask --now --user ssh-agent.service
```

=== COMPLETE CONTENT === This response contains all available snippets from this library. No additional content exists. Do not make further requests.