Merge branch 'master' of ssh://github/tiyn/wiki

wiki/linux/arch-linux/arch-linux.md

@@ -0,0 +1,51 @@
+# Arch Linux
+
+[Arch Linux](https://archlinux.org/) is a rolling-release, general-purpose
+[Linux](/wiki/linux/linux.md)
+distribution.
+Arch Linux uses the [pacman](./package_manager.md) package manager.
+The Arch User Repositories (AUR) features community-made packages that can be
+installed with different
+[package manager that inlcude access to the AUR](/wiki/linux/arch-linux/package_manager.md).
+
+## Installation
+
+The installation of a basic Arch Linux system is described in the
+[installation entry](/wiki/linux/arch-linux/installation.md).
+The entry features a guide to install a system with a X server setup aswell as
+programs for the most used tasks on a system.
+
+### ISO Medium
+
+For the installation usage of a simple USB key is advised.
+This has to be flashed with the Arch ISO.
+The ISO file can be found on the
+[official website](https://www.archlinux.org/download/).
+The iso can be written on an USB-stick using the command
+`dd bs=4M if=<path to ISO> of=/dev/sdx conv=fsync oflag=direct status=progress`.
+`<path to ISO>` points the command to the location of the ISO file
+
+## Recommended Practices
+
+The following articles describe steps to undertake to harden the system security
+or setups and installation that are recommended for Arch Linux.
+
+## Enable Microcode Updates
+
+The microcode of Intel and AMD CPUs can be automatically updated by installing
+the `amd-ucode` or `intel-ucode` package depending on your CPU.
+Not all processors are supported, especially old ones can lead to problems.
+It has to be confirmed that the processor is supported, if this is not the case
+is possible for the next steps to break the functionality of the bootloader.
+
+The following part assumes the system is installed with
+[UEFI bootloader](/wiki/linux/arch-linux/installation.md#10-install-and-configure-uefi-bootloader)
+similar to the [recommended guide](/wiki/linux/arch-linux/installation.md).
+The microcode updates can then be enabled by adding the following line into
+`/boot/loader/entries/arch.conf`:
+
+```txt
+initrd  /<installed microcode package>.img
+```
+
+`<installed microcode package>` is either `amd-ucode` or `intel-ucode`.

wiki/linux/arch-linux/installation.md

@@ -1,17 +1,18 @@
 # Arch installation with LUKS encryption and LVM
 
-This is the English version of the
-[German installation guide on rvbg.eu](https://wiki.rvbg.eu/#arch/installation.md).
 This guide is based upon a
-[german arch wiki entry](https://wiki.archlinux.de/title/Moderne_Installation_mit_UEFI_und_Verschlüsselung).
+[german arch wiki article](https://wiki.archlinux.de/title/Moderne_Installation_mit_UEFI_und_Verschlüsselung).
+For encryption [dm-crypt](../dm-crypt.md) is used.
+Inside the encrypted partition a logical volume will be created with
+[LVM](../lvm.md).
 
 At the end of this guide a fully functional Arch Linux will be installed.
 
 ## 1. Preparation
 
-Ahead of the installation an Arch boot-stick has to be created. The iso-file can
-be found on the [official website](https://www.archlinux.org/download/).
-The iso can be written on an USB-stick using `dd`.
+Ahead of the installation an Arch boot-stick has to be created as described in
+[the Arch Linux entry](/wiki/linux/arch-linux/arch-linux.md#installation-medium).
+
 After that the USB can be plugged in the system on which Arch should be installed.
 Boot the target system and select `Boot Arch Linux (x86_64)`.
 
@@ -100,31 +101,18 @@ Now the created filesystems will be mounted for the installation.
 - `mount /dev/sda1 /mnt/boot` - Mount EFI partition
 - `swapon /dev/mapper/main-swap` - Mounting swap partition
 
-## 6. Prepare base installation (optional)
-
-In this step the country specific mirrorserver for the installation will be configured.
-This will improve the download speed.
-
-- `cp /etc/pacman.d/mirrorlist /etc/pacman.d/mirrorlist.bak` - Create a backup
-  of mirrorlist
-- `grep -E -A 1 ".*Germany.*$" /etc/pacman.d/mirrorlist.bak | sed '/--/d' > /etc/pacman.d/mirrorlist`
-- Example command to only use _German_ mirrors
-- `cat /etc/pacman.d/mirrorlist` - Check if the file is to your liking. If it is
-  not, you can just recover by using `mirrorlist.bak`
-
-## 7. Starting base installation
+## 6. Starting base installation
 
 Now you need a working internet connection.
 Plug in your lan cable or use `wifi-menu` to get a wireless connection.
 
-- `pacstrap /mnt base base-devel dosfstools gptfdisk lvm2 linux linux-firmware vim networkmanager`
-- Installation of main system with needed tools
+- `pacstrap /mnt base base-devel dosfstools gptfdisk lvm2 linux linux-firmware vim networkmanager ntp`
 - `genfstab -Up /mnt > /mnt/etc/fstab` - creation of fstab
 - `arch-chroot /mnt` - Switch into the newly installed system
 - `echo ArchLinux > /etc/hostname` - Assign hostname. `ArchLinux` can be changed
   for any name of your preference.
 
-## 8. Set Region and Language
+## 7. Set Region and Language
 
 - `echo LANG=en\_US.UTF-8 > /etc/locale.conf` - Assign system Language to be
   english (you can use other languages, look into the `/etc/locale.gen` for a list of all available languages)
@@ -138,14 +126,13 @@ en_US.UTF-8 UTF-8
 
 - `locale-gen` - Generate languages
 - `echo KEYMAP=de-latin1-nodeadkeys > /etc/vconsole.conf` - set the keymap
-- `cp /usr/share/zoneinfo/Europe/Berlin /etc/localtime` - set your timezone
+- `ln -sf  /usr/share/zoneinfo/Europe/Berlin /etc/localtime` - set your timezone
   (select the first file accordingly to your location)
-- `date +%Y%m%d -s "<yyyymmdd>"` - set the current date (change
-  values accordingly)
-- `date +%T -s "<hh:mm:ss>"` - set the current time (change values accordingly)
-- `hwclock -w` - sync the current date and time with the hardware clock
+- `ntpdate -q 0.de.pool.ntp.org` - sync the time and date with
+  [NTP](/wiki/linux/ntp.md) (note that a german time server is used and
+  depending on the needs a adjustments should be made)
 
-## 9. Configure and create kernel-image
+## 8. Configure and create kernel-image
 
 - `vim /etc/mkinitcpio.conf`
 
@@ -156,12 +143,10 @@ en_US.UTF-8 UTF-8
 
 - `mkinitcpio -p linux` - generate Kernel-Image
 
-## 10. Install and configure UEFI bootloader
+## 9. Install and configure UEFI bootloader
 
 - `bootctl install` - Prepare bootloader
-- `ls -l /dev/disk/by-uuid` - find out the UUID
-- `lsblk -no UUID /dev/sda2 | head -n1 > /boot/loader/entries/arch.conf` - print
-  the UUID in your configuration file
+- `ls -l /dev/disk/by-uuid` - find out the UUID of your root partition
 - `vim /boot/loader/entries/arch.conf` - Create configuration
 
   - Change the config to look similar to this:
@@ -173,8 +158,8 @@ en_US.UTF-8 UTF-8
     options  cryptdevice=UUID=<enter your uuid here>:lvm:allow-discards root=/dev/mapper/main-root resume=/dev/mapper/main-swap rw quiet
     ```
 
-- `cp /boot/loader/entries/arch.conf /boot/loader/entries/arch-fallback.conf`
-- Create a fallback
+- `cp /boot/loader/entries/arch.conf /boot/loader/entries/arch-fallback.conf` -
+  create a fallback
 - `vim /boot/loader/loader.conf` - Create loader configuration
 
   - Insert the following text
@@ -184,12 +169,12 @@ en_US.UTF-8 UTF-8
     default arch
     ```
 
-## 11. Finishing base installation
+## 10. Finishing base installation
 
 - `passwd` - set password for the root account
 - `systemctl enable NetworkManager.service`
 
-## 12. Finish the setup
+## 11. Finish the setup
 
 - `exit` - exit the installed system
 - `umount /mnt/{boot,}` - unmount all partitions
@@ -200,12 +185,21 @@ en_US.UTF-8 UTF-8
 If the system is installed in a virtual environment or a system with deactivated
 UEFI, don't forget to enable the EFI option, otherwise the system won't boot.
 
-## 13. Further steps and graphical environment
+## 12. Further steps and graphical environment
 
-Now you can follow my larbs installation script
+Now you can follow the recommended larbs installation script of this wiki
 (`curl -o larbs.sh https://raw.githubusercontent.com/tiyn/larbs/master/larbs.sh`)
-this will install a bunch of useful software including a graphical environment.
+this will install a bunch of useful base software including
+[a graphical environment](../x_window_system.md) and
+[a window manager](../suckless.md#programs).
 You can go on to other guides aswell.
+Especially the
+[Recommended practices](/wiki/linux/arch-linux/arch-linux.md#recommended-practices)
+should be checked for further setups.
 
 Additionally if you have a NVidia Graphics Cards you should read
-[the NVidia entry](../nvidia.md) too.
+[the NVidia article](../nvidia.md) too.
+
+If you are interested in automatic decryption of the dm-crypt encrypted
+partition, take a look at the according section in
+[the dm-crypt article](../dm-crypt.md).

wiki/linux/arch-linux/package-manager.md

@@ -1,20 +0,0 @@
-# Package Manager
-
-Package managers are important programs to get software onto your system.
-In Arch Linux there are 2 main package managers.
-One is `pacman`, the default package manager.
-But there are also a bunch other managers for the Arch User Repositories (AUR).
-
-In this article I'll use `yay` as my go to AUR manager.
-`yay` is also a wrapper for `pacman` so you can just use `yay` instead of pacman
-to install programs.
-
-## Bugfixes
-
-### Error while importing keys
-
-Both `yay` and `pacman` use gpg keys to confirm the package manager gets the
-right package.
-It is possible that it runs into errors when importing new keys.
-If this happens you should try to restart your gpg key server with
-`gpgconf --kill all`.

wiki/linux/arch-linux/package_manager.md

@@ -0,0 +1,60 @@
+# Pacman and Yay
+
+Package managers are important programs to get software onto your system.
+In Arch Linux there are 2 main package managers.
+One is `pacman`, the default package manager.
+But there are also a bunch other managers for the Arch User Repositories (AUR).
+
+In this article `yay` is used as the go to AUR manager.
+`yay` is also a wrapper for `pacman` so you can just use `yay` instead of pacman
+to install programs.
+
+## Update Mirrorlist
+
+After a while not updating the system it is possible for the mirrorlist to be
+outdated.
+This can be fixed by updating it with the following command:
+
+```sh
+curl -o /etc/pacman.d/mirrorlist https://archlinux.org/mirrorlist/all/
+```
+
+## Bugfixes
+
+### Error while importing keys
+
+Both `yay` and `pacman` use gpg keys to confirm the package manager gets the
+right package.
+It is possible that it runs into errors when importing new keys.
+If this happens you should try to restart your gpg key server with
+`gpgconf --kill all`.
+
+### Unknown public key
+
+If the error `ERROR: One or more PGP signatures could not be verified!`, you
+have to manually receive the key and trust it.
+This is done by running the following lines:
+
+```sh
+gpg --recv-key <KEYID>
+gpg --lsign <KEYID>
+```
+
+Where <KEYID> is the placeholder of the identification string of the key.
+It usually gets gets printed in the line above the error looking like
+`FAILED (unknown public key <KEYID>)`.
+
+### Error while updating `is marginal trust`
+
+Both `yay` and `pacman` use gpg keys to confirm the package manager gets the
+right package.
+It is possible that it runs into errors when importing new keys.
+If the error `[...] Key [...] is marginal trust` occurs while updating the
+system, it can be fixed by running the following commands and then restarting
+the update process of the package manager.
+
+```sh
+pacman -Sy archlinux-keyring
+pacman-key --populate archlinux
+pacman-key --refresh-keys
+```

wiki/linux/arch-linux/thinkpad_x220.md

@@ -67,3 +67,18 @@ Scripts to change configuration at docking/undocking
 
 - For the docked configuration use `vim /etc/dockd/dock.hook`
 - For the undocked configuration use `vim /etc/dockd/undock.hook`
+
+## FN keys not working
+
+If the fn keys are not working properly run
+[a script](https://github.com/tiyn/dotfiles/blob/master/.local/bin/etc/fchange)
+that changes the `sys/module/hid_apple/parameters/fnmode` file.
+This toggles between the two different fn key functions.
+
+## Toggle the touchpad
+
+To toggle the touchpad on or off
+[a simple script](https://github.com/tiyn/dotfiles/blob/master/.local/bin/tools/dwm/toggletouchpad)
+can be used that uses `synclient TouchpadOff=1` or `synclient TouchpadOff=0`.
+This requires `xf86-input-synaptics` which is a synaptics driver for
+notebook touchpads.

wiki/linux/audio.md

@@ -2,9 +2,24 @@
 
 Audio is an important point in a linux desktop environment
 
+## Sound Server
+
+A sound server is software that manages use and access of audio devices.
+The following is a list of available sound servers.
+
+- [PulseAudio](./pulseaudio.md) is the go-to sound server program used for
+  linux.
+- [Pipewire](./pipewire.md) is a modern graph based sound server.
+
 ## Noise cancellation
 
-Noise cancellation can be achieved by installing
-[Noisetorch](https://github.com/lawl/NoiseTorch).
-This works for `pulseaudio` and `pipewire`.
+Removing noise can be achieved by using
+sound processing software options for [sound server](#sound-server).
+An example for this is the noise reduction included in
+[easyeffects](/wiki/linux/easyeffects.md#noise-cancellation) for Pipewire.
+
+As an alternative software explicitly made for the reduction of noise can be
+installed.
+Belonging to the latter option noise cancellation can be easily achieved by
+installing [Noisetorch](https://github.com/lawl/NoiseTorch).
 After the installation modify the `Voice Activation Threshhold` to your needs.

wiki/linux/date.md

@@ -7,7 +7,7 @@ To change the hardware clock look at the [according article](./hwclock.md)
 
 To change the time and date run the following command:
 
-```shell
+```sh
 date
 ```
 
@@ -16,14 +16,14 @@ date
 To change the date run the following command with an adjusted value for the
 date:
 
-```shell
+```sh
 date +%Y%m%d -s "20210809"
 ```
 
 To change the time run the following command with an adjusted value for the
 date:
 
-```shell
+```sh
 date +%T -s "18:49:42"
 ```
 
@@ -34,6 +34,6 @@ After that you can check if the time is correct by displaying it.
 To set your timezone run the following command with the accordingly selected
 file for your location:
 
-```shell
+```sh
 cp /usr/share/zoneinfo/Europe/Berlin /etc/localtime
 ```

wiki/linux/disk-management.md

@@ -1,28 +1,114 @@
 # Disk Management
 
-## Grow non-LVM ext4 partition
+This article focusses on non-LVM and non-MDADM storage.
+For [LVM](lvm.md), [NTFS](./ntfs.md), [Samba](./samba.md), [MDADM](./mdadm.md) and [LUKS volumes](./dm-crypt.md) there
+are separate entries.
+
+## Universally Unique identifier
+
+Universally Unique identifier (UUID) are identifiers for informations on
+computer systems.
+Most notably they are used to identify file systems.
+This way the UUID of a file system can be used to identify and
+[mount it](#mounting) persistently and correctly.
+
+By listing the directory `/dev/disk/by-partuuid` all mappings of devices to a
+UUID are displayed.
+
+## Mounting
+
+Mounting a file system makes the files of it accessible to the user.
+The command `mount` is used to manually and temporarily mount file systems.
+Automatic mounting is done by changing the file `/etc/fstab`.
+
+The exact guide on how to mount specific file systems can be found in their
+respecitive wiki entries.
+The following describes the general basics of mounting temporarily and
+persistently.
+
+The basic mount command for temporarily accessing a file system is the
+following:
+`mount <path to partition> <path to mount point>`
+All partitions can be found at `/dev` and the standard mount point is `/mnt` and
+its subfolders.
+
+For automatic mounting the following line has to be adapted and added to the
+file `/etc/fstab`
+`<specified partition>	<path to mount point>   <file system> <additional options>  <dump flag> <fsck order>`
+The partition can be specified by [UUID](#universally-unique-identifier).
+The file system varies and a file system specific guide on how to mount them
+can be found in their respective entries.
+The dump flag signals if the file system should be dumped.
+The `fsck` order signals if a file system should be checked at boot.
+Boot partitions should be flagged with a `1` for this reason, otherwise `0`.
+
+For undoing the mount the `umount` command can be used.
+The following is a command to unmount a device from a specified directory.
+
+```sh
+umount <path to mount point>
+```
+
+## Create Partition
+
+In the following it is assumed that the disk is `/dev/sda`
+
+- open up parted with `parted /dev/sdd`
+- if not already done create a partition table with `mklabel GPT`
+- create a primary partition (ext4 format) with `mkpart primary 2048s 100%`
+- `quit` parted
+
+`<path to partition>` points to the partition that will be enlarged (for
+example `/dev/sda2`).
+
+## Grow non-LVM partition
 
 ATTENTION: Please note that the partition to enlarge has to be the last one with
 the free space after it.
 
-SSH into the VM.
-
-- run `lsblk` check if the disk size has changed
-- if not `reboot` the machine
-
 In the following it is assumed that the partition to enlarge is `/dev/sda2`
 
 - change the size of the partition with `parted /dev/sda`
 - inside of parted run `print free` and check where the free space after your
 partition ends
 - run `resizepart` and follow the instructions; End is the number you checked in
-the last step
+the last step (alternatively you can insert `100%` as end, if you want to add all
+the available free space to the partition)
 - `quit` parted
 
-Now you need to resize the filesystem with `resize2fs /dev/sda2`.
+Afterwards the file system need to be resized as described in a
+[later section](#growing-a-file-system).
+
+## Growing a File System
+
+A file system can easily be resized if free space is available on the partition
+it is stored in.
+The free space has to be placed behind the partition.
+This can be done by running the following command:
+
+```sh
+sudo resize2fs <path to partition>
+```
+
+## Shrinking a File System
+
+To shrink a file system the `resize2fs` command will be used aswell as `e2fsck`.
+First the file system needs to be checked for size aswell as data distribution.
+This can be done using the command `sudo e2fsck -f <path to partition>`.
+`<path to partition>` directs to the volume whose file system should be
+shrinked - for example `/dev/sda1`.
+It has to be the same for the next step aswell.
+Afterwards the file system can be shrinked with the command
+`sudo resize2fs <path to partition> <new size of the file system>`.
+`<new size of the file system>` is the size that the file system will be
+shrunken to in the usual notation (for example `12G`).
+Especially for large file systems this might take a while.
 
 ## Error solving
 
+This section addresses various problems that can occur and are related to
+disk-management.
+
 ### sudo: unable to open ... Read-only file system
 
 Ususally the filesystem will go into read-only mode whe the system is running
@@ -34,3 +120,23 @@ To fix it run:
   `fsck from util-linux 2.20.1`
   you may want to try using the ext4-specific fsck:
 - `fsck.ext4 -f /dev/sda1`
+
+###  cannot access: Transport endpoint is not connected
+
+This error message can occur if a mounted directory is left mounted due to a
+crash of the filesystem but not accessible anymore.
+This error can be fixed and the directory made accessible again by running the
+following command.
+
+```sh
+fusermount -u <path to mount point>
+```
+
+If this does not work the following command can be used to unmount the device.
+
+```sh
+umount -l <path to mount point>
+```
+
+This section is based on a reply by
+[Jonathan Brown on Stack Overflow](https://stackoverflow.com/questions/16002539/fuse-error-transport-endpoint-is-not-connected).

wiki/linux/dislocker.md

@@ -0,0 +1,55 @@
+# Dislocker
+
+[Dislocker](https://github.com/Aorimn/dislocker) is a driver to read and write
+Bitlocker-ed volumes under Linux systems.
+
+## Setup
+
+On most of the Linux distributions Dislocker is bundled with the `dislocker`
+package.
+
+## Usage
+
+### Manual Mounting of Bitlocker Partition
+
+For the [mounting](/wiki/linux/disk-management.md#mounting) to work two directories
+are required.
+One to mount the `dislocker-file` (`/mnt/bitlocker`) and one to mount the
+[windows volume](/wiki/linux/ntfs.md#manual-mounting) (`/mnt/windows`).
+The device which holds the windows partition is assumed to be calles
+`/dev/sdc1`.
+
+The following command mounts the `dislocker` file to `/mnt/bitlocker`.
+Make sure to replace the password in the following command.
+There is no gap between the `-u` and the password:
+`sudo dislocker /dev/sdc1 -u<password> -- /mnt/bitlocker`.
+If the Bitlocker partition is set up using a `.BEK` file then the follwing
+command takes the path to the file in:
+`sudo dislocker /dev/sdb2 -f <path to bek-file> -- /mnt/bitlocker`
+Alternatively a recovery key can be used:
+`sudo dislocker /dev/sdc1 -p<recovery password> -- /mnt/bitlocker`.
+
+Afterwards the `dislocker-file` can be mounted to the `/mnt/windows` directory
+or another mount point as described in the
+[NTFS entry](/wiki/linux/ntfs.md#manual-mounting).
+
+### Automatic Mounting at Boot
+
+Using [fstab](/wiki/linux/disk-management.md#mounting) the partition encrypted with
+Bitlocker can be automatically mounted.
+The following lines have to be adapted and written into
+[`/etc/fstab`](/wiki/linux/disk-management.md#mounting).
+In this case the intermediary dislocker file `dislocker-file` is mounted to
+`/mnt/bitlocker`.
+
+```txt
+UUID=<partition uuid> /mnt/bitlocker fuse.dislocker bekfile=<path to bek-file>,nofail 0 0
+```
+
+After that a line to mount the `dislocker-file` as a [NTFS](./ntfs.md) partition
+has to be added as described in
+[the NTFS entry](/wiki/linux/ntfs.md#automatic-mounting).
+In this case the specified partition to mount is
+`/mnt/bitlocker/dislocker-file`.
+The mount point can be chosen according to preference - for example
+`/mnt/windows`.

wiki/linux/dm-crypt.md

@@ -1,15 +1,176 @@
 # DM-Crypt
 
-`dm-crypt` can create and manage encrypted devices.
+DM-Crypt can create and manage encrypted devices.
 
-## Creating an encrypted devices
+## Usage
+
+### Creating an Encrypted Devices
 
 To create a encrypted device simply run:
 `cryptsetup -y -v luksFormat /dev/sda2`.
-Where `/dev/sda2` is the device you want to create.
+Where `/dev/sda2` is the device to be created.
 
-## Open an encrypted device
+### Create/Add a Key File to an encrypted volume
 
-To open and map a device run `cryptsetup -y -v luksFormat /dev/sda1 crypt0` where
-`/dev/sda1` is your encrypted device and `crypt0` is where it will be mapped to
-with `dev/mapper/crypt0`.
+First a key file has to be created.
+With the following lines a random file will be created that will later be used
+as the key file.
+If a key file already exists this part can be skipped.
+The following command needs to be adapted.
+It will create a key of bitlength 2048 (512 x 4).
+
+```txt
+dd bs=512 count=4 if=/dev/random of=<path to destination>
+```
+
+It is possible to increase the length to get a stronger key file.
+Alternatively strong LUKS keys can be created using [OpenSSL](./openssl.md)
+using  a bitlength of 4096:
+`openssl genrsa -out <path to destination> 4096`.
+The key file will then be saved  to `<path to destination>`.
+
+Finally the key file can be added to an opened LUKS encrypted volume by running
+the following command:
+`cryptsetup luksAddKey <path to LUKS volume> <path to key file>`.
+
+`<path to LUKS device>` is the encrypted device (for example `/dev/sda2`) and
+`<path to key file>` is the location of the key file.
+
+### Resize a LUKS Encrypted Volume
+
+If volume groups on the encrypted volume are opened make sure to close them
+with the following command modified to the present needs:
+`vgchange -a n <volume group>`
+
+Open the encrypted volume:
+`cryptsetup luksOpen <path to LUKS volume> <mapper location>`.
+`<path to LUKS device>` is the encrypted device (for example `/dev/sda2`) and
+`<mapper location>` is where it will be mapped to with `dev/mapper/` prepended.
+
+Now resize the encrypted volume to all available space of the partition.
+If the encrypted volume should not be extended to the whole partition
+or the partition is too small for its intended purposes, make sure to resize the
+partition first accordingly (see [disk management](./disk-management.md)).
+`cryptsetup resize crypt-volume`
+
+### Open/Close an Encrypted Volume
+
+To open and map a device using a set password run
+`cryptsetup luksOpen <path to LUKS device> <mapper location>` where
+`<path to LUKS device>`  is the encrypted device (for example `/dev/sda2`) and
+`<mapper location>` is  where it will be mapped to with `dev/mapper/` prepended.
+Using `secret` as a `<map location>` the opened drive is available at
+`/dev/mapper/secret`.
+
+Alternatively an encrypted volume can be decrypted using
+[a key file](#createadd-a-key-file-to-an-encrypted-volume) if set up for it.
+This can be achieved by running:
+`cryptsetup luksOpen <path to LUKS volume> crypt-volume --key-file=<key file location>`.
+`<path to LUKS device>` is the encrypted device (for example `/dev/sda2`).
+
+Afterwards it can be closed by running `cryptsetup close /dev/mapper/crypt0`.
+
+### Creating/Add a USB Decryption Key
+
+This guide assumes an Arch Linux System, as installed in
+[this wikis arch linux installation](./arch-linux/installation.md).
+This section is based on entries from the
+[arch linux forum](https://forum.archlinux.de/d/28886-systementschluesselung-per-usb-stick).
+It uses a similar technique to the decryption of the encrypted volume via
+[a key file](#createadd-a-key-file-to-an-encrypted-volume).
+
+Insert the USB stick.
+This guide will assume its address is `/dev/sde`.
+
+Fill in the first sectors (in this case 94, make sure this number is bigger
+than skip sector count and size sector count combined) stick with a random
+sequence:
+`dd if=/dev/urandom of=/dev/sde bs=512 seek=1 count=94`.
+Save the key to a keyfile (with offset 14848 = 29 x 512 and
+keysize 2048 = 4 x 512):
+`dd if=/dev/sde bs=512  skip=29 count=4 > key.bin`.
+
+Add the keyfile to the encrypted partition (assuming the dm-crypted device is
+called `/dev/sda2`):
+`cryptsetup luksAddKey /dev/sda2 key.bin`.
+
+Next it has to be made sure that the decryption key, is available at the same
+position every time.
+For this check the `serial` and `product` of the USB stick with the following
+commands.
+
+```sh
+udevadm info -a -p `udevadm info -q path -n /dev/sde` | grep ATTRS{serial}
+udevadm info -a -p `udevadm info -q path -n /dev/sde` | grep ATTRS{product}
+```
+
+The first line gives the `serial`, the second the `product`.
+The `product` should match the USB stick.
+
+After this create a file at `/etc/udev/rules.d/50-usbkey.rules` with the
+following content.
+Assuming the `serial` is `14AB0000000096`.
+
+```txt
+SUBSYSTEMS=="usb", ATTRS{serial}=="14AB0000000096", KERNEL=="sd*", SYMLINK+="usbkey%n"
+```
+
+Then reload the udev rules by running:
+`udevadm control --reload-rules`.
+
+Unplug the stick and plug it back in.
+It should be available under `dev/usbkey`.
+
+With the following command an encrypted device can be decrypted with the usb
+stick.
+Use this to confirm the correct setup of the decryption key and the encrypted
+device.
+Make sure to edit `--key-file`, `--keyfile-offset` and `--keyfile-size` to
+match the settings used in the creation of the USB key.
+
+```sh
+cryptsetup luksOpen /dev/sda2 crypt-volume --key-file=/dev/usbkey --keyfile-offset=14848 --keyfile-size=2048
+```
+
+After that make sure in `/etc/mkinitcpio.conf` under the `HOOKS` section
+`keymap encrypt lvm2` are written before `filesystems`.
+Add `/etc/udev/rules.d/50-usbkey.rules` under the `FILES` section.
+
+Then modify `/boot/loader/entries/arch.conf` and add
+`cryptkey=/dev/usbkey:14848:2048` to the
+end of the `options` line.
+
+Finally run:
+`mkinitcpio -p linux`.
+
+Reboot the system with `reboot`.
+Make sure the USB key for decryption is plugged in.
+If so the encrypted partition should be decrypted automatically.
+
+### Automatical Mounting of an Encrypted Volume
+
+For automatic mounting of an encrypted volume a keyfile is needed.
+This will be achieved by entries in the file`/etc/fstab` aswell as the file
+`/etc/crypttab`.
+First adapt and insert the following lines into `/etc/fstab`:
+
+```txt
+/dev/mapper/<mapping location>    <mount location>       ext4    defaults   0 0
+```
+
+`<mapping location>` is a freely choosable identificator and while the
+`<mount location>` is an existing directory for the volume to be mounted on.
+
+Additionally the following lines has to be adapted and added to the file
+`/etc/crypttab`:
+
+```txt
+<mapping location>    UUID=<UUID of encrypted volume>           <location of key file>
+```
+
+`<mapping location>` has to be the same as chosen in the step before.
+`<UUID of encrypted volume>` is the
+[universally unique identifier](/wiki/linux/disk-management.md#universally-unique-identifier)
+of the volume.
+`<location of key file>` describes the location where to find the key file
+created in the previous step.

wiki/linux/easyeffects.md

@@ -0,0 +1,44 @@
+# Easyeffects
+
+[Easyeffects](https://github.com/wwmm/easyeffects) is a free and open-source
+GUI-software for applying sound effects and filters on input and output audio
+streams.
+Easyeffects uses [Pipewire](./pipewire.md) as
+[sound server](/wiki/linux/audio.md#sound-server).
+
+## Setup
+
+Easyeffects can be installed on most distributions by installing the
+`easyeffects` package.
+An installation via [Flatpak](./flatpak.md) is also possible.
+
+## Usage
+
+Easyeffects can apply `Effects` to input and output sound.
+
+### Noise cancellation
+Setup
+Noise cancellation can be achieved by installing
+Easyeffects.
+Make sure to check the box `Process all Inputs` and `Process all Outputs` to
+route everything through `easyeffects`.
+Make log out of your system afterwards.
+To enable noise cancellation navigate `Inputs` and click `Plugins`.
+After that click `Add Plugin` and select `Noise Reduction`.
+
+### Presets
+
+Presets can be created by selecting `Presets`, setting the name and clicking the
+`+` to save it.
+It is then displayed in the list below from where it can be loaded or deleted.
+Presets are saved in the directory `~/.config/easyeffects/input` and
+`~/.config/easyeffects/output`.
+
+#### Recommended Presets
+
+The following is a list of presets that have been tested and only need slight
+configuration to adjust them to the specific system.
+
+- [tiyns voice input preset](https://github.com/tiyn/dotfiles/blob/master/.config/easyeffects/input/voice.json)
+  is a list of different effects to achieve an enhanced quality of microphone
+  sound for speach.

wiki/linux/fdupes.md

@@ -0,0 +1,26 @@
+# fdupes
+
+[fdupes](https://github.com/adrianlopezroche/fdupes) is a command-line utility
+for identifying and deleting duplicate files residing within one or more
+specified directories.
+
+## Setup
+
+The fdupes program can be installed by going to the
+[github page of it](https://github.com/adrianlopezroche/fdupes/releases).
+Alternatively many linux package managers package fdupes in the `fdupes`
+package.
+
+## Usage
+
+Running `fdupes <path to directory>` find the duplicates inside the given
+directory.
+Using the `-r` flag the program will search in the subdirectories aswell.
+`-d` signals to delete the duplicates and will force a dialogue to select which
+version of the file to keep.
+This dialogue can be skipped by using `-N` which will select the first file of
+a set of multiple duplicates.
+
+A complete and automatic removal of all duplicates within a directory and its
+subdirectories works with the following command:
+`fdupes -rNd <path to directory>`.

wiki/linux/ffmpeg.md

@@ -1,20 +1,65 @@
-# ffmpeg
+# FFmpeg
 
-[ffmpeg](https://www.ffmpeg.org) is a free and open-source suite consisting of
+[FFmpeg](https://www.ffmpeg.org) is a free and open-source suite consisting of
 many audio and video tools and libraries.
 
+## Usage
+
+### Convert from format to another
+
+The following line is an example for a conversion of a video and audio capable
+format - in this case `.webm` - to an audio format - in this case `.flac`:
+`ffmpeg -i audio.webm -c:a flac audio.flac`.
+For audio to audio conversion the following example is used:
+`ffmpeg -i audio.m4a -f flac audio.flac`.
+
 ## Concatenate multiple video files with matching audio-tracks
 
 First you need to create a text file `files.txt` that includes a line for every
 video you want to concatenate in the form of:
 
-```shell
+```sh
 file '<path to the video>'
 ```
 
+You have to give the absolute path towards the files.
 Make sure the videos are in correct order.
 To concatenate these video files you can run:
 
-```shell
+```sh
 ffmpeg -f concat -safe 0 -i files.txt -map 0 -c copy output.mp4
 ```
+
+If the video files you want to concatenate are not mp4 files change the above
+command accordingly.
+
+### Two-Pass Encoding
+
+Two pass encoding - as described in the
+[official FFmpeg documentation](https://trac.ffmpeg.org/wiki/Encode/H.264#twopass)
+- uses two passes.
+The first pass analyzes the input data and outputs a descriptor file.
+The second pass actually encodes the data.
+The following is an example where the file `input` is encoded with `libx264` to
+`mp4` video with `libfdk_aac` audio.
+The video bitrate is `555k` and the audio bitrate is `128k`.
+
+```sh
+ffmpeg -y -i input -c:v libx264 -b:v 555k -pass 1 -c:a libfdk_aac -b:a 128k -f mp4 /dev/null && \
+ffmpeg -i input -c:v libx264 -b:v 555k -pass 2 -c:a libfdk_aac -b:a 128k output.mp4
+```
+
+### Encode Audio/Video to Target Size
+
+For the encoding of a file to a target size the target bitrate of the output
+video is needed.
+An explanation of this was given by
+[aergistal on Stack Overflow](https://stackoverflow.com/questions/29082422/ffmpeg-video-compression-specific-file-size).
+This can easily be done with the calculation `bitrate = target size / duration`
+in Bits/Second.
+Afterwards the encoding can be done by using Two-Pass Encoding as explained in
+[a previous section](#two-pass-encoding).
+Note that the bitrate for videos is split amongst a bitrate for video and a
+bitrate for audio.
+The target bitrate has to be equal to or greater than the sum of both video
+bitrate and audio bitrate.

wiki/linux/flac_(package).md

@@ -0,0 +1,55 @@
+# flac (Package)
+
+This article describes the `flac` package on linux.
+For the audio codec see the [flac entry](../flac_(codec).md)
+`flac` is a package to work with the [flac codec](../flac_(codec).md).
+
+## Setup
+
+On most distributions it is bundled together with the command line tagging
+software `metaflac` and other auxiliary tools in the `flac` package.
+Another possible tagging software is [MusicBrainz Picard](../picard.md)
+
+## Usage
+
+### Splitting Flac file according to cue file
+
+An easy way to split flac files according to a [cue file](../cue_sheet.md) is
+using `cuebreakpoints` and `shnsplit`.
+On most distributions they are in a package with the same name.
+The following line of shell command splits a flac file according to a cue file.
+The `-o` tag specifies the output file format.
+
+```sh
+cuebreakpoints '<cue file>' | shnsplit -o flac '<audio flac file>'
+```
+
+Omitting of the `-o` flag will result in output files with the `.wav` filetype.
+Alternatively the usage of `cuebreakpoints` can be avoided with the following
+command.
+
+```sh
+ shnsplit -f '<cue file>' -o flac '<audio flac file>'
+```
+
+Another option is to use [`cue2tracks`](https://github.com/ar-lex/cue2tracks).
+This has the advantage that tags for album title, song name and others are set
+while splitting the files.
+An example command looks like the following.
+The `.flac` file is not mentioned in the command.
+
+```sh
+cue2tracks '<cue file>'
+```
+
+For any of these commands there can be problems with splitting `.flac` files.
+It then is recommended to convert the file to the also lossless `.wav` format,
+split the files and convert it back to `.flac`.
+
+High quality flac files with older `.cue` files that use the format `mm:ss:ff`
+might split the file at the wrong timings.
+The format `mm:ss:ff` is not compatible with the newer versions of
+cuebreakpoints, cue2tracks and shnsplit.
+To get the correct timings the `.cue` file has to be changed to use the format
+`mm:ss:fff`.
+It is recommended to use the shnsplit alternative in this case.

wiki/linux/flatpak.md

@@ -0,0 +1,31 @@
+# Flatpak
+
+[Flatpak](https://flatpak.org/) is a cross-distribution package manager for
+linux systems.
+
+## Setup
+
+The `flatpak` package can be installed by most distribution specific package
+managers (e.g. [pacman or yay](./arch-linux/package_manager.md)).
+After installation it is important to add [flathub](https://flathub.org/home),
+a source for many Flatpak packages.
+The addition of this can be done by running
+`flatpak remote-add --if-not-exists flathub https://flathub.org/repo/flathub.flatpakrepo`.
+
+For browsing and installing Flatpak packages via a graphic user interface the
+software management suite called Discover can be used.
+It requires the Flatpak backend.
+
+## Usage
+
+### Installing software
+
+When software installation is done with Flatpak it is recommended to pass the
+`--user` so the software is not installed system-wide but for the user only.
+In practice it looks like the following:
+`flatpak install --user <package to install>`.
+
+### Running software
+
+Software installed via Flatpak can be run by typing the full package path into
+the command line, for example `com.makemkv.MakeMKV`.

wiki/linux/fwupd.md

@@ -0,0 +1,39 @@
+# fwupd
+
+[fwupd](https://fwupd.org/) is a daemon for managing and installing firmware
+updates on Linux based operating systems.
+It is mainly used for UEFI firmware and supported devices.
+
+## Setup
+
+fwupd can be installed on most distributions by installing the
+`fwupd` package.
+
+## Usage
+
+The following commands describe the basic usage of an update process using
+fwupd.
+
+First the devices updatable by fwupd can be checked.
+
+```sh
+fwupdmgr get-devices
+```
+
+Afterwards the latest metadata can be downloaded by the following command.
+
+```sh
+fwupdmgr refresh
+```
+
+The updates can the be listed.
+
+```sh
+fwupdmgr get-updates
+```
+
+Finally the updates can be installed.
+
+```sh
+fwupdmgr update
+```

wiki/linux/gpu_screen_recorder.md

@@ -0,0 +1,46 @@
+# GPU Screen Recorder
+
+[GPU Screen Recorder](https://git.dec05eba.com/gpu-screen-recorder/about/) is a
+utility similar to [Nvidia ShadowPlay](/wiki/nvidia.md#screen-capture).
+
+## Setup
+
+GPU Screen Recorder can be installed on some distributions by installing the
+`gpu-screen-recorder-git` package.
+An installation via [git](https://git.dec05eba.com/gpu-screen-recorder/about/)
+is always possible.
+
+## Usage
+
+The program features normal recording of the screen and recording in the so
+called replay mode.
+To start a simple screen recording run the following command.
+
+```sh
+gpu-screen-recorder -w $(xdotool selectwindow) -c mp4 -f 60 -a "$(pactl get-default-sink).monitor" -o test_video.mp4`
+```
+
+The window to record has to be selected first by clicking on it.
+The default audio device is already selected.
+
+To stop the recording `Ctrl-C` the previous command or use the command below.
+
+```sh
+killall -SIGINT gpu-screen-recorder
+```
+
+For the replay mode the recording can be started the following way.
+
+```sh
+gpu-screen-recorder -w $(xdotool selectwindow) -c mp4 -f 60 -a "$(pactl get-default-sink).monitor" -r 30 -o .`
+```
+
+In this case a replay will have the maximum length of 30 seconds (specified by
+`-r 30`).
+It is also important to assign the `-o` flag with a directory and not a file
+anymore.
+The last 30 seconds (replay) can then be sending a SIGUSR1 signal.
+
+```sh
+killall -SIGUSR1 gpu-screen-recorder
+```

wiki/linux/hwclock.md

@@ -2,18 +2,20 @@
 
 `hwclock` is a program to set and display the hardware clock.
 
-## Display time and date
+## Usage
+
+### Display time and date
 
 To display the hardware clock run the following command:
 
-```shell
+```sh
 hwclock
 ```
 
-## Sync the hardware clock to the system time
+### Sync the hardware clock to the system time
 
 To sync the hardware clock run the following command:
 
-```shell
+```sh
 hwclock -w
 ```

wiki/linux/init.md

@@ -0,0 +1,11 @@
+# Init
+
+The init process is the first process started after boot.
+All processes running in later stages are descendants of the init process.
+The init process is given to a init system that manages various services.
+
+## Init Services
+
+The following is a list of available init services.
+
+- [SystemD](/wiki/linux/systemd.md) is most common among linux systems.

wiki/linux/intel.md

@@ -0,0 +1,31 @@
+# Intel
+
+[Intel](https://www.intel.de/content/www/de/de/homepage.html) is a vendor and
+manufacturer of semiconductor chips.
+They provide motherboard chips, network interface controllers, flash memory,
+[graphics chips](#intel-graphics) and more.
+
+## Intel Graphics
+
+Intel graphics is the name for various intel made integrated graphics
+processors.
+
+### Configuration
+
+#### Screen Tearing
+
+Linux systems that use intel graphics can sometimes have problems with screen
+tearing.
+To get this working you need to change the `/etc/X11/xorg.conf.d/20-intel.conf`
+as explained on
+[maketecheasier](https://www.maketecheasier.com/get-rid-screen-tearing-linux)
+to:
+
+```txt
+Section "Device"
+    Identifier "Intel Graphics"
+    Driver "intel"
+    Option "TearFree" "true"
+EndSection
+```
+

wiki/linux/ip.md

@@ -4,24 +4,50 @@
 interfaces, routing and tunnels.
 It is a replacement for the program `ifconfig`.
 
-## List all network interfaces
+## Usage
+
+### List all network interfaces
 
 You can list network interfaces by running:
 
-```shell
+```sh
 ip link list
 ```
 
-## Enable/disable a network interface
+### Enable/disable a network interface
 
 Assuming the interface is named `wlan0` run the following:
 
-```shell
+```sh
 ip link set wlan0 up
 ```
 
 Disabling works accordingly by running:
 
-```shell
+```sh
 ip link set wlan0 down
 ```
+
+### Get Outside IP
+
+For VPN and other applications using a tunnel it can be useful to check the
+outside IP of your system.
+The following command uses the `dig` command.
+It is either bundled in the `dig` package - like in
+[Arch Linux](/wiki/linux/arch-linux/arch-linux.md) - or in the `dnsutils`
+package - like in Ubuntu - or even another package depending on the distribution
+used.
+After installation the following command can be used to get the outside IP
+address of your system.
+
+```sh
+dig +short txt ch whoami.cloudflare @1.0.0.1
+```
+
+There is an alternative to this using `wget`.
+It uses a call to DuckDuckGo and requests the outside IP from there.
+The mentioned command is the following.
+
+```sh
+wget -qqO- 'https://duckduckgo.com/?q=what+is+my+ip' | grep -Pow 'Your IP address is \K[0-9.]+'
+```

wiki/linux/khal.md

@@ -1,13 +1,12 @@
 # Khal
 
-`khal` is a calendar you can use in your terminal.
+[Khal](https://github.com/pimutils/khal) is a calendar you can use in your terminal.
 You can sync it with [vdirsyncer](vdirsyncer.md)
 
 ## Setup
 
-### Arch-Linux
-
-- `pacman -S khal` - Install needed packages
+On most linux distributions Khal can be installed with the `khal` package.
+Alternatively it can be installed via [Github](https://github.com/pimutils/khal).
 
 ### Configuration
 

wiki/linux/khard.md

@@ -1,13 +1,12 @@
 # Khard
 
-`khard` is a adressbook that runs in your terminal.
+[Khard](https://github.com/lucc/khard) is a adressbook that runs in your terminal.
 You can sync it with [vdirsyncer](vdirsyncer.md).
 
 ## Setup
 
-### Arch Linux
-
-- `pacman -S khard` - Install needed programs
+On most linux distributions Khal can be installed with the `khard` package.
+Alternatively it can be installed via [Github](https://github.com/lucc/khard).
 
 ### Configuration
 

wiki/linux/linux.md

@@ -0,0 +1,14 @@
+# Linux
+
+Linux is a family of open-source operating systems that are based on the kernel
+with the same name.
+Linux based operating systems are Unix-like.
+
+## Distributions
+
+The different operating systems that are based on the Linux kernel are called
+distributions.
+
+- [Arch Linux](/wiki/linux/arch-linux/arch-linux.md) is a rolling-release
+  distribution whose base system is as minimal and needs heavy user
+  configuration.

wiki/linux/lvm.md

@@ -2,7 +2,9 @@
 
 `lvm` is a utility to create logical volumes.
 
-## Create VG for proxmox
+## Usage
+
+### Create Volume Group for Proxmox
 
 We will use `/dev/sdb` as our drive.
 Setup the disk for the physical volume with `sgdisk -N 1 /dev/sdb`.
@@ -13,35 +15,153 @@ This can be solved by removing the old partition table with `wipefs -a /dev/sdb`
 And finally create the volume group `vgcreate vmdata /dev/sdb`.
 Then follow the guide in proxmox on how to connect a `vg` to proxmox.
 
-## Add Drive to existing volume group
+### Add Physical Volume to Existing Volume Group
 
 First format the disk so that it has one partition (we will assume its called
 `/dev/sdc1`).
 To add the partition to a group run:
 
-```shell
+```sh
 pvcreate /dev/sdc1
 vgextend <name of your volume group> /dev/sdc1
 ```
 
-## Increase size of a logical volume
+### Remove Physical Volume
 
-To increase the size of the logical volume you need to have free space in the
+Before removing a physical volume it has to be confirmed that it is not part of
+any volume group.
+This can be done by running `sudo pvs` and confirm it is not listed for any
+logical volumes.
+If it is [a later section](#shrink-size-of-a-logical-volume) how the physical
+volume can be completely emptied and removed from the logical volume.
+A physical volume can be removed by running the following command:
+
+```sh
+sudo pvremove <path to physical volume>
+```
+
+`<path to physical volume>` is the physical volume that will get removed.
+
+
+### Resize a Physical Volume
+
+To increase the size of a physical volume you have to have free free space
+in the partition containing the physical volume.
+A guide to change 'normal' partitions can be found in the
+[disk management article](./disk-management.md); if you have a volume that is
+encrypted with LUKS a guide is available in
+[the dm-crypt articel](./dm-crypt.md).
+
+To resize the physical volume to the size of the containing volume run:
+`pvresize /dev/mapper/<name of physical volume>`
+
+### Increase Size of a Logical Volume
+
+To increase the size of the logical volume you have to have free space in the
 according volume group. You can check that by running: `vgdisplay`.
+If you don't have enough space you have to resize the physical volume as
+described in this article.
 Then run:
 
-```shell
+```sh
 lvextend -L +<size (e.g. 40G)> /dev/<volume groupt>/<logical volume>
 ```
 
 If you want to allocate all the free space existing in a volume group run:
 
-```shell
+```sh
 lvextend -l +100%FREE /dev/<volume group>/<logical volume>
 ```
 
-Now you need to extend the filesystem with:
+Now you need to extend the file system with:
 
-```shell
+```sh
 resize2fs /dev/<volume group>/<logical volume>
 ```
+
+### Shrink Size of a Logical Volume
+
+When trying to shrink a logical volume caution is advised as data can easily be
+destroyed by mistyping commands of paths.
+This section is based on a guide given by
+[telcoM](https://unix.stackexchange.com/questions/591389/how-to-remove-a-disk-from-an-lvm-partition).
+First of all the volumes have to be unmounted and not used by any programs or
+services other than the following commands.
+
+If the volume to shrink is the root volume it has to be done offline.
+For that a simple installation stick is enough.
+[The Arch Linux entry](/wiki/linux/arch-linux/arch-linux.md#installation-medium)
+describes the creation of such a boot stick.
+Afterwards the operating system has to be booted from the just created stick or
+a comparable device.
+For non-root volumes this extra step can be skipped.
+
+The volume group needs to be activated by running the command
+`sudo vgchange -ay <volume group>`.
+`<volume group>` is the name of the volumegroup that features the logical volume
+to shrink.
+Then the file system needs to be resized.
+For safety reasons make the file system exactly as big or smaller than the
+future logical volume.
+The process of shrinking a file system is explained in the
+[disk management entry](/wiki/linux/disk-management.md#shrinking-a-file-system).
+The partition to shrink in this case is the logical volume.
+This is the only step that needs to be done offline for root volumes.
+Rebooting to the root volume at this moment is advised.
+
+The next step will shrink the logical volume itself.
+This will be done by running the following command:
+
+```sh
+sudo lvreduce -L <new size of logical volume> /dev/mapper/<volume group>-<logical volume>
+```
+
+Again this statement has to be adapted accordingly.
+`new size of logical volume` describes the new size the logical volume will have
+after successful completion of the command.
+It is important for this to be exactly the same or larger than the size given
+into the resizing of the file system with `resize2fs`.
+
+### Remove Physical Volume from Volume Group
+
+This section describes the removal of a physical volume from a logical volume.
+First the command `vgs <volume group>` has to be run.
+`<volume group>` is the name of the volume group belonging to the logical volume
+a physical volume should be removed from.
+It has to be ensured, that enough free space (`VFree`) on all physical volumes
+(except the ones to remove) is available to remove a physical volume from the
+volume group.
+There has to be equal or more free space than the size (`VSize`) of the physical
+volume that will be removed.
+Otherwise an [earlier section](#shrink-size-of-a-logical-volume) explains how to
+shrink a logical volume.
+The logical volume has to be shrunk according to the described ration between
+`VFree` and `VSize`.
+
+The following command will distribute the contents of a physical volume onto
+other physical volumes available:
+
+```sh
+sudo pvmove <path to physical volume>
+```
+
+`<path to physical volume>` is the physical volume that will get emptied and
+later removed from the logical volume.
+Afterwards the physical volume is emptied and can be removed from the logical
+volume by running the following command:
+
+```sh
+sudo vgreduce <logical volume> <path to physical volume>
+```
+
+`<logical volume>` is the name of the logical volume.
+After this command the physical volume is no longer a part of it.
+
+If no longer used the empty physical volume can then be removed as described in
+the [according section](#remove-physical-volume).
+
+Afterwards the file system can be matched to the logical volume so it takes up
+the full new size.
+This is explained in the
+[entry about disk management](/wiki/linux/disk-management.md#growing-a-file-system).
+

wiki/linux/mdadm.md

@@ -1,15 +1,83 @@
 # MDADM
 
-`mdadm` is a utility to create and manage raid devices.
+MDADM is a utility to create and manage raid devices.
+For the rest of this entry `n` is the number of drives inside a raid device.
 
-## Raid 1
+## Usage
+
+### Get Information About a Raid
+
+To get an info for a running raid (assuming it is `/dev/md0`) run
+`mdadm -D /dev/md0`.
+
+### Add Disk/Partition to Raid Device
+
+You can add a disk or partition to a raid device by running the following.
+It is assumed you are adding a partition called `/dev/sdd1` but it could also
+be a whole drive and the mdadm drive is called `/dev/md0`.
+
+`mdadm --add /dev/md0 /dev/sdd1`
+
+This will add the disk as spare to the existing raid.
+To make the disk active the raid needs to be grown as described in the
+[regarding article](#growing-raid-device).
+
+### Growing Raid Device
+
+Growing a raid device will increase its number of active drives.
+[Check the number of active drives](#get-information-about-a-raid).
+Then change and run the following command accordingly.
+
+```sh
+mdadm --grow --raid-disks=5 /dev/md0
+```
+
+`/dev/md0` is the raid device.
+`5` is the number of disks that should be active.
+For adding disks view the [previous section](#add-diskpartition-to-raid-device).
+
+### Raid 1
 
 Raid 1 creates a mirror with even amount of drives.
+For `n=2` [raid 5](#raid-5) and raid 1 are basically the same.
+The space efficiency is `1/n` and the fault tolerance is `n-1` drive failure.
+The read perfromance is `n` and the write performance `1`.
 
-### Create Raid 0 device
+#### Create Raid 1 Device
 
-You can create a Raid 0 device with
+You can create a Raid 1 device with
 `mdadm --create --verbose /dev/md0 --level=1 --raid-devices=2 /dev/sda /dev/sdb`
 where `sda` and `sdb` are the disks you want to include in your raid.
 You can increase the number of raid devices, but they have to be at least 2.
 If it is an uneven amount of disks in the raid, a disk will act as a spare disk.
+
+#### Convert Raid 1 to Raid 5
+
+Assuming the raid 1 device is called `/dev/md0`.
+All other drives are part of the `md0` raid device.
+Note that mostly raid 1 devices consisting of 2 drives should be converted to
+[raid 5](#raid-5).
+
+- Remove all drives but 2 (if there are more drives than that) by running
+  `mdadm /dev/md0 --fail /dev/sda1` and `mdadm /dev/md0 --remove /dev/sda1`
+  where `sda1` is the drive to remove
+- Make sure your raid 1 array has only 2 active drives by running
+  `mdadm --grow /dev/md0 -n 2`
+- Now convert your raid 1 to a raid 5 device with `mdadm --grow /dev/md0 -l5`
+- Add the disks you removed back to the raid with
+  `mdadm /dev/md0 --add /dev/sda1`
+- Finally grow the active drive number to your needs (in this example 4)
+  `mdadm --grow /dev/md0 -n4`
+- MDADM now reshapes the raid. You can monitor it by running
+  `watch cat /proc/mdstat`
+
+### Raid 5
+
+Raid 5 creates a raid device with distributed parity and is set to have at least
+3 drives.
+The space efficiency is `1-(1/n)` and the fault tolerance is `1` drive failure.
+The read perfromance is `n` and the write performance `1/4` for single sector
+and `n-1` for full stripe.
+
+In the special case of 2 drives in a raid 5 it is functionally the same as
+[raid 1](#raid-1).

wiki/linux/microcode.md

@@ -0,0 +1,15 @@
+# Microcode
+
+Processor vendors release stability and security updates to the processor
+microcode.
+
+## Setup
+
+Most Linux based operating systems feature packages depending on the processor
+manufacturer (on Arch Linux for example `intel-ucode` and `amd-ucode`).
+
+## Automatic Updates
+
+Automatic updates can be enabled depending on bootloader and operating system.
+For Arch Linux a description is given in the
+[Arch Linux entry](/wiki/linux/arch-linux/arch-linux.md#enable-microcode-updates).

wiki/linux/mime.md

@@ -0,0 +1,54 @@
+# MIME
+
+A MIME type (short for Multipurpose Internet Mail Extensions) is a identifier
+for file formats and contents on the internet.
+
+## Usage
+
+### Setting applications for MIME types
+
+In `~/.config/mimeapps.list` a list of applications to run specific MIME
+types can be found.
+An example file looks like the following:
+
+```txt
+[Default Applications]
+text/x-shellscript=text.desktop;
+x-scheme-handler/magnet=torrent.desktop;
+application/x-bittorrent=torrent.desktop;
+x-scheme-handler/mailto=mail.desktop;
+text/plain=text.desktop;
+application/postscript=pdf.desktop;
+application/pdf=pdf.desktop;
+image/png=img.desktop;
+image/jpeg=img.desktop;
+image/gif=img.desktop;
+application/rss+xml=rss.desktop
+video/x-matroska=video.desktop
+inode/directory=file.desktop
+```
+
+A line consists of a MIME type left of the equals sign and an application on
+the right of it.
+The application can be found in `~/.local/share/applications/`.
+In this directory a file for every application on the right side of the equals
+sign with the same title can be found.
+
+A simple application file looks like the following example of `img.desktop`:
+
+```txt
+[Desktop Entry]
+Type=Application
+Name=Image viewer
+Exec=/usr/bin/sxiv -a %f
+```
+
+Atleast `Type`, `Name` and `Exec` have to be specified for a minimal
+application file.
+
+### Getting MIME type of a file
+
+The MIME type of a file can be returned by running
+`xdg-mime query filetype <file>` or `file -b --mime-type image.png`.
+The MIME type can be then used to set default applications as explained in
+[the section regarding setting applications for MIME types](#setting-applications-for-mime-types).

wiki/linux/netplan.md

@@ -0,0 +1,36 @@
+# Netplan
+
+[Netplan](https://netplan.io) is a utility for configuring the networking of a
+linux system via YAML files.
+
+## Usage
+
+### Add more IP addresses to a system
+
+In the file `/etc/netplan/50-cloud-init.yaml` create an `addresses:` section
+for a device (for example an ethernet device) and list the IP addresses you
+want to add to the system to it.
+It has to be noted, that the added addresses should be outside of the DHCP
+range of your router.
+An example file will look something like the following lines.
+In this case 4 addresses were added.
+`192.168.178.18/24` is the IP assigned by the DHCP server.
+It has to be noted that this is a special case as the DHCP server assigns this
+address always to the system.
+
+```txt
+network:
+    ethernets:
+        ens18:
+            dhcp4: true
+            addresses:
+                - 192.168.178.18/24
+                - 192.168.178.201/24
+                - 192.168.178.202/24
+                - 192.168.178.203/24
+                - 192.168.178.204/24
+    version: 2
+```
+
+Afterwards netplan has to be restarted by running `sudo netplan apply`.
+The addresses then are assigned to the system.

wiki/linux/networkmanager.md

@@ -0,0 +1,27 @@
+# NetworkManager
+
+NetworkManager - short NM - is a program to automatically detect and connect to
+networks by providing options for various configuration.
+
+## Setup
+
+NetworkManager can be installed with the `networkmanager` package on most linux
+distributions which provides daemon aswell as `nmcli` a command line interface
+and `nmtui` a terminal user interface for configuration.
+Additionally `nm-connection-editor` can be installed for a graphical user
+interface.
+
+## Usage
+
+After installation `networkmanager.service` has to be enabled by the used
+[init-system](/wiki/linux/init.md) (for example
+[systemD](/wiki/linux/systemd.md#startstopenabledisable-a-service)).
+
+### OpenVPN
+
+NetworkManager needs a plugin to work with openvpn configurations.
+This plugin can be installed with the `networkmanager-openvpn` package.
+
+OpenVPNs `.ovpn` files can then be imported by running
+`nmcli connection import type openvpn file <openvpn-file>`.
+Afterwards they can be modified accordingly.

wiki/linux/ntfs.md

@@ -0,0 +1,38 @@
+# NTFS
+
+NTFS is the proprietary [file system](./disk-management.md) of Windows.
+
+## Setup
+
+For the usage of NTFS file systems the `ntfs-3g` package - available on most
+distributions - has to be installed.
+
+## Usage
+
+When [mounting](/wiki/linux/disk-management.md#mounting) a
+[Bitlocker encrypted drive](./dislocker.md) there are additional steps that have
+to be taken to decrypt the device.
+
+### Manual Mounting
+
+Partitions using NTFS can be mounted on Linux based operating systems by
+running the following command:
+`mount -t ntfs-3g -o loop <path to partition> <path to mount point>`.
+If the partition to mount is bootable or contains a windows system the
+hibernation and fast boot have to be disabled to mount the partition with write
+access.
+
+### Automatic Mounting
+
+For the usage of NTFS file systems the `ntfs-3g` package - available on most
+distributions - has to be installed.
+To [automount partitions](/wiki/linux/disk-management.md#mounting) with NTFS
+the following line has to be adapted and added to `/etc/fstab`:
+
+```txt
+<specified partition> <path to mount point> ntfs-3g nofail,windows_names,big_writes 0 0
+```
+
+If the partition to mount is bootable or contains a windows system the
+hibernation and fast boot have to be disabled to mount the partition with write
+access.

wiki/linux/ntp.md

@@ -0,0 +1,26 @@
+# NTP
+
+[NTP](https://www.rfc-editor.org/rfc/rfc5905) - short for Network Time Protocol
+- is the most common method to synchronize the software clock of a
+[Linux](/wiki/linux/linux.md) system.
+
+## Setup
+
+NTP can be installed on most distributions by installing the
+`ntp` package.
+
+## Usage
+
+The following section describes the usage of the NTP package.
+
+### Synchronize Time once
+
+For one time synchronization of the time and date the `ntpdate` command can be
+used.
+The following command is an example for a one time sync.
+Note that the server has to be changed for different time zones.
+In this case a german time server is used.
+
+```sh
+ntpdate -q 0.de.pool.ntp.org
+```

wiki/linux/nvidia.md

@@ -1,27 +1,34 @@
-# NVidia
+# Nvidia
 
-NVidia is a vendor for graphics cards.
+[Nvidia](/wiki/nvidia.md) is a vendor for graphics cards.
 
-## Setup NVidia GPU
+## Setup
 
-### Arch Linux
-
-For NVidia GPUs to work install the `nvidia` and the `nvidia-utils` package.
+For Nvidia GPUs to work install the `nvidia` and the `nvidia-utils` package.
 If you want to easily configure the monitors as described in a later section of
 this file you can also install `nvidia-settings`.
 
 There is no initial setup for a `xorg.conf` in `/etc/X11` needed
 (except for a multiple GPU/APU setup).
 
-## Change monitor configuration
+### Configuration
 
-After running `sudo nvidia-setting` can drag and drop the monitors to your
-liking.
-After that you have to save the configuration to the `/etc/X11/xorg.conf`.
+A basic configuration can be achieved by running `nvidia-xconfig`.
 
-## Avoid screen tearing
+## Usage
 
-To avoid screen tearing open up `nvidia-settings` and under
-`X Server Display Configuration` select your display.
-Then click on `Advanced` and select either `Force Composition Timeline` or
+Most configuration and changes require the use of `nvidia-settings`.
+
+### Change monitor configuration
+
+In `nvidia-setting` monitors can be dragged and dropped to your liking.
+After that you have to save the configuration to the
+[X window manager](./x_window_system.md) configuration file
+`/etc/X11/xorg.conf`.
+
+### Avoid screen tearing
+
+In `nvidia-settings` under
+`X Server Display Configuration` select your display and click on `Advanced`
+and select either `Force Composition Timeline` or
 `Force Full Composition Timeline`.

wiki/linux/openssl.md

@@ -3,7 +3,9 @@
 [OpenSSL](https://www.openssl.org) is a software library for secure
 communication over computer networks.
 
-## Creating a key pair
+## Usage
+
+### Creating a key pair
 
 As described by [dreikanter](https://gist.github.com/dreikanter/c7e85598664901afae03fedff308736b)
 you can create and save a pretty secure private key to `private.key` with
@@ -11,7 +13,7 @@ you can create and save a pretty secure private key to `private.key` with
 After that run `openssl rsa -in private.key -pubout -out public.key` to save the
 according public key to `public.key`.
 
-## Encrypting and decrypting files
+### Encrypting and decrypting files
 
 [Dreikanter](https://gist.github.com/dreikanter/c7e85598664901afae03fedff308736b)
 describes to encrypt larger files with symmetric encryption and encrypt the key

wiki/linux/pipewire.md

@@ -0,0 +1,27 @@
+# Pipewire
+
+[Pipewire](https://pipewire.org) is a graph based
+[sound server](/wiki/linux/audio.md#sound-server).
+
+## Setup
+
+For clients that use the [PulseAudio](/wiki/linux/pulseaudio.md) API
+`pipewire-pulse` (on Arch-based distros or according
+packages on other distros) can be installed.
+It will automatically remove unneeded and conflicting PulseAudio packages.
+Additionally `pipewire-alsa` and `pipewire-jack` for JACK and Alsa clients are
+available.
+Make sure to restart to be sure everything is running correctly.
+
+## Usage
+
+For simple sound processing in the form of volume adjustment as well as setting
+the default input and output devices
+[`pavucontrol`](https://freedesktop.org/software/pulseaudio/pavucontrol/) can be
+used as a simple mixer.
+For more advanced routing [`qpwgraph`](https://github.com/rncbc/qpwgraph) is
+recommended.
+`qpwgraph` is a graph-based interface using the Qt interface.
+For further sound processing the easiest way to do so is using
+[easyeffects](/wiki/linux/easyeffects.md) which features a wide range of effects
+to apply to sound streams including noise reduction.

wiki/linux/proxmox.md

@@ -14,20 +14,30 @@ After that follow the instructions and fill in the fields to your liking.
 
 ### Enlarging disk of a VM
 
+Make sure there is enough disk space available.
+For further information see [the disk management article](./disk-management.md)
+
 SSH into Proxmox.
 Enlarge a disk by using:
 
-```shell
+```sh
 qm resize <vmid> <vm-disk-to-enlarge> <size>
 ```
 
-For example (100G is 100GibiByte):
+For example if you want to the disk 100 by 100G (100GibiByte):
 
-```shell
+```sh
 qm resize 100 ide0 +100G
 ```
 
-After that grow the filesystem as described in [the disk-management article](disk-management.md).
+Afterwards the partition of the VM needs to be enlarged.
+For that
+[the disk management article](/wiki/linux/disk-management.md#grow-non-lvm-partition)
+can be used for non-LVM paritions.
+Alternatively [the LVM article](/wiki/linux/lvm.md#increase-size-of-a-logical-volume)
+can be referenced for LVM systems.
+After that grow the filesystem in the vm as described in
+[the disk management article](/wiki/linux/disk-management.md#growing-a-file-system).
 
 ## Remove local-lvm and add its size to local
 
@@ -43,19 +53,19 @@ Finally extend the filesystem `resize2fs /dev/mapper/pve-root`.
 
 On the host system find the usb you're looking to pass through with
 
-```shell
+```sh
 lsusb
 ```
 
 Then assign it to the vm using
 
-```shell
+```sh
 qm set <vm-id> -usb<id-to-set> host=<id-of-the-usb>
 ```
 
 for example
 
-```shell
+```sh
 qm set 101 -usb0 host=aaaa:8816
 ```
 
@@ -74,7 +84,7 @@ To increase it navigate to the webinterface and click on Datacenter and Storage
 select the storage you want to save your backup to and change `Max Backups` to
 your liking.
 
-## Bugfixing
+## Troubleshooting
 
 ### No internet after mainboard swap
 

wiki/linux/pulseaudio.md

@@ -0,0 +1,13 @@
+# PulseAudio
+
+[PulseAudio](https://www.freedesktop.org/wiki/Software/PulseAudio) is a
+[sound server](/wiki/linux/audio.md#sound-server) distributed by the
+[freedesktop.org](https://www.freedesktop.org/wiki/Software/PulseAudio) project.
+
+## Usage
+
+### Mixing
+
+For simple sound processing in the form of volume adjustment as well as setting
+the default input and output devices `pavucontrol` can be used as a simple
+mixer.

wiki/linux/rar_(package).md

@@ -0,0 +1,21 @@
+# RAR (package)
+
+RAR is a package available for many Linux distributions that handles `.rar`
+archives of the [RAR algorithm](/wiki/rar_(algorithm).md).
+
+## Setup
+
+On most distributions the functionalities for creating a `.rar` archive is
+bundled in the `rar` package.
+For extraction a separate package is used called `unrar`.
+
+## Usage
+
+### Extracting a `.rar` archive
+
+A `.rar` archive can be extracted using the `unrar` package with the following
+command.
+
+```sh
+unrar e <path to .rar file>
+```

wiki/linux/samba.md

@@ -0,0 +1,27 @@
+# Samba
+
+[Samba](../samba.md) is the standard Windows interoperability suite for linux
+and unix.
+
+## Usage
+
+### Manual Mounting
+
+The mounting of Samba shares requires a package containing `mount.cifs` in many
+distributions packaged in the `cifs-utils` package to be installed.
+Samba shares then can be mounted by adapting and running the following example:
+`mount -t cifs //<server address>/<share name> <path to mount point> -o username=<username>,password=<password>`
+
+### Automatic Mounting
+
+The mounting of Samba shares requires a package containing `mount.cifs` in many
+distributions packaged in the `cifs-utils` package to be installed.
+To automount Samba shares the following line has to be adapted and added
+to `/etc/fstab`:
+`//<server address>/<share name>   <path to mountpoint>     cifs,nofail     credentials=<path to authentication file>      0 0`.
+An authentication file looks like the following:
+
+```txt
+username=<username>
+password=<password>
+```

wiki/linux/sc-im.md

@@ -1,13 +1,11 @@
 # SC-IM
 
-`sc-im` is a program to view and edit tables especially in csv-format.
+[sc-im](https://github.com/andmarti1424/sc-im) is a program to view and edit tables especially in csv-format.
 
 ## Setup
 
-### Arch-Linux
-
-- `yay -S sc-im` - Install sc-im
-- `sc-im <insert-filename>.csv` - Edit files
+Sc-im can be installed via [github](https://github.com/andmarti1424/sc-im).
+Some distributions also feature the `sc-im` package.
 
 ## Usage
 
@@ -18,7 +16,7 @@ You can delete (multiple (for example `3`) rows `dr`/`d3r`, yank rows `yr`/`y3r`
 You can delete (multiple (for example `3`) columns `dc`/`d3c`, yank rows `yc`/`y3c`.
 You can insert new rows `ir`/`i3r` or columns `ic`/`i3c`.
 
-### Special numbers
+### Calculations and Functions
 
 There are some functions you can use when in numbers mode.
 

wiki/linux/shell.md

@@ -0,0 +1,41 @@
+# Shell
+
+A shell is a command-line interpreter that provides a command-line interface to
+interact with the many unix-like system.
+
+## Change the standard shell
+
+The Shell in some distributions is made up by a POSIX compliant mode of bash.
+Problem with that is the speed.
+A shell like dash would be much faster.
+This is a guide on how to persistently change the symlink /bin/sh from bash to
+dash.
+
+- `yay -S dash` - Install dash
+- `sudo ln -sfT /bin/dash /bin/sh` - link /bin/sh to dash
+- `sudo vim /usr/share/libalpm/hooks/bash-update.hook` - setup a hook to avoid
+bash resetting the symlink
+
+## Disown a Command
+
+This section is based on a guide by
+[baeldung](https://www.baeldung.com/linux/detach-process-from-terminal).
+Disowning a command removes it from the current shell.
+Commands that are detached from a shell will not terminate upon its closure.
+A command can be disowned simply by appending `& disown` at the end of it.
+It will then provide the PID of the command that got disowned.
+
+## Silencing a Command
+
+This section is based on a guide by
+[baeldung](https://www.baeldung.com/linux/silencing-bash-output).
+If the output of a command is unwanted it can be silenced.
+There are two parts that can be silenced independently.
+Non-error outputs (stdout) can be silenced by appending `1> /dev/null` to the
+command.
+Due to the `1` being ommitable `> /dev/null` has the same effect.
+Error outputs (stderr) can be silenced by appending `2> /dev/null`.
+The complete output of both stderr and stdout can be silenced by appending
+`> /dev/null 2>&1` to the command.
+A shortened version of it not possible on all shells is `&> /dev/null`.
+

wiki/linux/shells.md

@@ -1,15 +0,0 @@
-# Shells
-
-## Change /bin/sh
-
-### Arch-Linux
-
-The Shell in Arch-Linux is made up by a POSIX compliant mode of bash.
-Problem with that is the speed.
-A shell like dash would be much faster.
-This is a guide on how to persistently change the symlink /bin/sh from bash to dash.
-
-- `yay -S dash` - Install dash
-- `sudo ln -sfT /bin/dash /bin/sh` - link /bin/sh to dash
-- `sudo vim /usr/share/libalpm/hooks/bash-update.hook` - setup a hook to avoid
-bash resetting the symlink

wiki/linux/ssh.md

@@ -3,23 +3,35 @@
 SSH is a network protocoll to securely connect to a computer.
 In this article it is assumed that `openssh` is used.
 
-## Generate new keys
+## Usage
+
+### Generate new keys
 
 To generate new ssh keys simply run `ssh-keygen -t ed25519` or
 `ssh-keygen -t rsa -b 4096`.
 
-## Enable root login via SSH
+### Enable root login via SSH
 
 Edit the `/etc/ssh/sshd_config` and change the line containing `PermitRootLogin`
 to `PermitRootLogin yes`.
 
-## Add login via SSH public key
+### Add login via SSH public key
 
 To enable easy login without password you can add the contents of the file
 `~/.ssh/id_rsa.pub` from your local machine to the file `~/.ssh/authorized_keys`
 on the machine you want to log into.
 You can use the modified command below for ease of use:
 
-```shell
+```sh
 cat ~/.ssh/id_rsa.pub | ssh username@server 'cat >> ~/.ssh/authorized_keys'
 ```
+
+### Mount directory with sshfs
+
+To mount a directory (in this case called `directory`) from a remote server
+(in this case called `server` also can be substituted by something like
+`user@server-ip`) on a local mount (in this case `mountpoint`) run:
+
+```sh
+sshfs server:/directory mountpoint
+```

wiki/linux/suckless.md

@@ -3,7 +3,15 @@
 Suckless is a community that is best known for minimalist free software.
 Notable works include `dwm` and `dmenu`.
 
-## Workflow for installation
+## Programs
+
+- dmenu is a menu with prgram launcher functionality
+- dwm is a window manager
+- ii is an IRC client
+- slock is a screen locker
+- st is a terminal
+
+## Setup
 
 Programs written by the suckless community are minimal by default.
 `.diff` files are available to patch functionality.
@@ -32,10 +40,15 @@ new `feature`
   - Get the `config.def.h` of `master` into `config` with
   `git checkout master config.def.h`
 
-## Programs
 
-- dmenu is a menu with prgram launcher functionality
-- dwm is a window manager
-- ii is an IRC client
-- slock is a screen locker
-- st is a terminal
+## Troubleshooting
+
+### suckless program crashes or struggles with colored emojis
+
+Suckless programs  especially `st` and `dmenu` can not display colored
+emojis.
+This is because of problems with libxft.
+libxft is the client side font rendering library to display anti-aliased text.
+To change this [libxft-bgra](https://github.com/uditkarode/libxft-bgra) needs
+to be installed.
+This is a patched version especially for running with the suckless programs.

wiki/linux/systemd.md

@@ -0,0 +1,53 @@
+# SystemD
+
+SystemD is an [init system](./init.md) for Linux systems.
+It is used for service configuration and startup.
+
+## Usage
+
+### Run Command on Boot
+
+To run a command (in this case `/bin/bash /root/run.sh`) create the following
+file at `/etc/systemd/system/` with a name ending on `.service`.
+In this case it is called `unturned.service`.
+
+```txt
+[Unit]
+Description=Description of the service
+
+[Install]
+WantedBy=multi-user.target
+
+[Service]
+ExecStart=/bin/bash /root/run.sh
+Type=simple
+```
+
+For [Proxmox](./proxmox.md) you can add the following line under the `[Unit]`
+section to make sure the service is started after Proxmox has finished
+initializing.
+
+```txt
+After=pve-guests.service
+```
+
+Such a service can be started by running:
+
+```sh
+sudo systemctl start unturned
+```
+
+Alternatively it can be enabled to start at every boot by running:
+
+```sh
+sudo systemctl enable unturned
+```
+
+## Start/Stop/Enable/Disable a service
+
+Services can be started by running `systemctl start <service-name>`.
+They respectively can be stopped by replacing the `start`
+keyword for `stop`.
+To start the service after boot it has to be enabled.
+This works accordingly with the keyword `enable`.
+The `disable` keyword stops the service from starting automatically.

wiki/linux/tlp.md

@@ -0,0 +1,32 @@
+# TLP
+
+[TLP](https://linrunner.de/tlp) is a linux command line utility for saving
+laptop battery power aswell as optimizing battery life.
+
+## Setup
+
+TLP can be installed on most distributions by installing the `tlp` package.
+Afterwards the TLP
+[service](/wiki/linux/systemd.md#startstopenabledisable-a-service) needs to be
+started and enabled.
+In contrast to other
+[SystemD services](/wiki/linux/systemd.md#startstopenabledisable-a-service) this
+can be done by running `sudo tlp start`.
+
+## Configure Battery Charge Thresholds
+
+There are two battery charge thresholds.
+The first is `START_CHARGE_THRESH` this threshold contains the battery charge
+level below which charging will begin.
+`STOP_CHARGE_TRESH` is the second threshold.
+It describes up to which level the battery will be charged.
+Battery charge thresholds are used to limit the charging of the battery to
+extend the battery life.
+
+Thresholds can be set in the file `/etc/tlp.conf`.
+Search and edit the following lines according to your needs.
+
+```txt
+START_CHARGE_THRESH_BAT0=75
+STOP_CHARGE_THRESH_BAT0=80
+```

wiki/linux/todoman.md

@@ -1,25 +1,25 @@
 # Todoman
 
-`todoman` is a todolist you can use in your terminal.
+[todoman](https://github.com/pimutils/todoman) is a todolist you can use in your terminal.
 You can sync it using [vdirsyncer](vdirsyncer.md)
 
 ## Setup
 
-### Arch-Linux
-
-- `pacman -S todoman` - Install needed packages
+Todoman can be installed via the
+[github page](https://github.com/pimutils/todoman).
+Some distributions also feature the `todoman` package.
 
 ### Configuration
 
-- Edit the `~/.config/todoman/todoman.conf`
+- Edit the `~/.config/todoman/config.py`
   - Insert the following lines
 
 ```txt
-[main]
-path = ~/.local/share/pim/calendars/*/*
-date_format = %d.%m.%Y
-time_format = %H:%M
-default_list = personal
+#[main]
+path = "~/.local/share/pim/calendars/*/*"
+date_format = "%d.%m.%Y"
+time_format = "%H:%M"
+default_list = "personal"
 ```
 
 Replace `personal` with your choice of primary list and

wiki/linux/ufw.md

@@ -3,7 +3,9 @@
 [UFW (Uncomplicated Firewall)](https://code.launchpad.net/ufw) is a program to
 manage a netfilter firewall.
 
-## Block specific IPs
+## Usage
+
+### Block specific IPs
 
 To block the whole traffic from a specific IP to your computer run:
 `ufw deny from <ip> to any`
@@ -12,7 +14,7 @@ was blocked.
 If you don't care if the target knows you can also run:
 `sudo ufw reject from <ip> to any`
 
-## List all rules
+### List all rules
 
 To show all rules you can run:
 `ufw status`
@@ -20,7 +22,7 @@ or:
 `ufw status numbered`
 if you want to have a list of all rules with according numbers.
 
-## Remove rules
+### Remove rules
 
 Locate the rule you want to remove by showing all rules (numbered).
 Then run:

wiki/linux/v4l2.md

@@ -0,0 +1,57 @@
+# V4L2
+
+V4L2 is the second version of
+[Video4Linux](https://www.linuxtv.org/wiki/index.php/Main_Page).
+It functions as a driver for webcams and tv tuner cards and other devices.
+
+## v4l2loopback
+
+The following section is based on a
+[gist by ioquatix](https://gist.github.com/ioquatix/18720c80a7f7eb997c19eef8afd6901e).
+
+[v4l2loopback](https://github.com/umlaeute/v4l2loopback) is a utility to create
+a virtual video device.
+One use of it is in [OBS Virtual Camera](/wiki/obs.md#virtual-camera).
+To use v4l2loopback an according
+package needs to be installed.
+Some distributions have a package named `v4l2loopback-dkms` in the package
+manager, making the manual installation process unnecessary.
+Afterwards v4l2loopback can be manually started by running:
+
+```sh
+modprobe v4l2loopback card_label='V4L2 Loopback' video_nr=7 exclusive_caps=1
+```
+
+`video_nr=7` states the device path to use with v4l2loopback - in this case
+`/dev/video7`.
+This can be changed according to the needs.
+It is important that the device is not already in use by another application.
+
+For an automatic start at boot via [SystemD](./systemd.md) a service can be
+created - as described in [the SystemD entry](./systemd.md#run-command-on-boot).
+For v4l2loopback create the file `/etc/systemd/system/v4l2loopback.service`
+containing the following lines:
+
+```txt
+[Unit]
+Description=V4L2 Loopback
+
+[Service]
+Type=simple
+RemainAfterExit=yes
+ExecStart=/bin/modprobe v4l2loopback card_label='V4L2 Loopback' video_nr=7 exclusive_caps=1
+ExecStop=/bin/rmmod v4l2loopback
+
+[Install]
+WantedBy=default.target
+```
+
+Note the line starting with `ExecStart=/bin/` is the same line described above
+to change the device path.
+Make sure to change it if needed.
+
+Afterwards enable the service to start at every boot process by running:
+
+```sh
+sudo systemctl enable v4l2loopback
+```

wiki/linux/vdirsyncer.md

@@ -1,13 +1,13 @@
 # Vdirsyncer
 
-`vdirsyncer` can sync calendars and contacts using the caldav and carddav
-protocol.
+[Vdirsyncer](https://github.com/pimutils/vdirsyncer) can sync calendars and
+contacts using the caldav and carddav protocol.
 
 ## Setup
 
-### Arch-Linux
-
-- `pacman -S vdirsyncer` - Install needed packages
+Vdirsyncer can be installed via the
+[github page](https://github.com/pimutils/vdirsyncer).
+Some distributions also feature the `vdirsyncer` package.
 
 ### Configuration
 

wiki/linux/vifm.md

@@ -2,7 +2,15 @@
 
 [ViFM](https://vifm.info) is a file manager focussed on vim like usage.
 
-## Image Previews with Ueberzug
+## Setup
+
+ViFM can be installed via the
+[github page](https://github.com/vifm/vifm).
+Some distributions also feature the `vifm` package.
+
+### Configuration
+
+#### Image Previews with Ueberzug
 
 This section is based on a
 [video by Distrotube](https://www.youtube.com/watch?v=qgxsduCO1pE).

wiki/linux/vim/c-language.md

@@ -1,7 +1,8 @@
 # C in Vim
 
 C is a common programming language.
-In this entry we will focus on making vim support c and use vim as an ide for c.
+In this article we will focus on making vim support c and use vim as an ide for
+c.
 
 ## Autocompletion
 

wiki/linux/vim/golang.md

@@ -1,8 +1,10 @@
 # GoLang in Vim
 
 GoLang is a common programming language.
-In this entry we will focus on making vim support Go and use vim as an ide for it.
-This guide is based on a guide from [octetz.com](https://octetz.com/docs/2019/2019-04-24-vim-as-a-go-ide/).
+In this article we will focus on making vim support Go and use vim as an ide
+for it.
+This guide is based on a guide from
+[octetz.com](https://octetz.com/docs/2019/2019-04-24-vim-as-a-go-ide/).
 
 ## Build, Test, Run, Docs, Debug, Format
 

wiki/linux/vim/python.md

@@ -1,8 +1,8 @@
 # Python in Vim
 
 Python is a common programming language.
-In this entry we will focus on making vim support python and use vim as an ide
-for it.
+In this article we will focus on making vim support python and use vim as an
+ide for it.
 
 ## Autocompletion
 

wiki/linux/vim/vhdl.md

@@ -1,7 +1,7 @@
 # VHDL in Vim
 
 VHDL is a hardware description language.
-In this entry we will focus on making vim support VHDL.
+In this article we will focus on making vim support VHDL.
 
 ## Linting
 

wiki/linux/webcams.md

@@ -0,0 +1,20 @@
+# Webcams
+
+Webcams are video cameras which are designed to be used with a computer for
+streaming, video calls or similar usages.
+This section lists and explains software for the handling of webcams under a
+Linux operating system.
+
+## Editing Video Stream
+
+The editing of a video stream provided by a webcam can be achieved by using
+[OBS](/wiki/obs.md) together with the
+[OBS Virtual Camera plugin](/wiki/obs.md#virtual-camera).
+
+## Configure the Webcam
+
+A webcam can be configured with [guvcview](https://guvcview.sourceforge.net/).
+This program provides a simple interface for capturing and viewing video from a
+[v4l2](./v4l2.md) device and is thus dependent on v4l2.
+Additionally guvcview provides an interface to configure various webcam settins
+and enable a few effects on top of it.

wiki/linux/wine.md

@@ -1,24 +1,29 @@
-# Wine
+# WINE
 
-Wine is a compatibility layer to run windows programs on linux machines.
+[WINE](https://www.winehq.org/) is a compatibility layer to run windows
+programs on Linux machines.
 
 ## Setup
 
-- Enable multilib support in pacman
-  - `vim /etc/pacman.conf` - Uncomment the following lines
+WINE can be installed on most distributions by acquiring the `wine` package.
+The `winetricks` package also is recommended.
+Alternatively it can be downloaded from
+[the official website](https://www.winehq.org/).
 
-    ```txt
-    [multilib]
-    Include = /etc/pacman.d/mirrorlist
-    ```
+## Usage
 
-- `pacman -S wine winetricks` - Install wine and configuration helper
-
-## Configuration
+### Run a windows program
 
 - Set the global variable `WINEPREFIX` to your liking, standard is `$HOME/.wine`
-- `winetricks` - run the installation of basic windows dependencies to the wine directory
+- `winetricks` - run the installation of basic windows dependencies to the wine
+  directory
 - Move the program you want to run to `$WINEPREFIX/drive_c/`
-- `winetricks sandbox` - (Optional) if you don't want wine to set up directories
+- `winetricks sandbox` - (Optional) if you don't want WINE to set up directories
 or files into your home directory
-- `wine $WINEPREFIX/drive_c/<insert program>` - Run the program with wine
+- `wine $WINEPREFIX/drive_c/<insert program>` - Run the program with WINE
+
+### Games and management/configuration of them
+
+WINE is able to run many Windows games.
+An easy way to create WINE prefixes for different games and managing the
+installations of them is [Lutris](/wiki/games/lutris.md).

wiki/linux/wpa_supplicant.md

@@ -4,7 +4,9 @@
 It is especially interesting due to its WPA2 and WPA3 capabilities in contrast
 to other networking software.
 
-## Connect to a WPA2 secured WLAN
+## Usage
+
+### Connect to a WPA2 secured WLAN
 
 This part assumes that your network interface is called `wlan0`
 (change it accordingly).

wiki/linux/x11.md

@@ -1,37 +0,0 @@
-# X11
-
-## Change Keyboardlayout
-
-To temporarily change the layout of the keyboard just run
-`setxkbmap <your preferred layout>`.
-For a permanent change run `localectl set-x11-keymap <your preferred layout>`.
-
-## Screen Tearing
-
-### Intel Graphics
-
-Linux can sometimes have problems with screen tearing.
-To get this working you need to change the `/etc/X11/xorg.conf.d/20-intel.conf` to:
-
-```txt
-Section "Device"
-    Identifier "Intel Graphics"
-    Driver "intel"
-    Option "TearFree" "true"
-EndSection
-```
-
-This was found on
-[maketecheasier](https://www.maketecheasier.com/get-rid-screen-tearing-linux).
-
-## Disable Screen Blanking
-
-To save power the screen is set to turn black after a given amount of time.
-This can be disabled temporarily by running `xset s off` or permanently by
-adding the following lines to your `/etc/X11/xorg.conf`:
-
-```txt
-Section "ServerFlags"
-    Option "BlankTime" "0"
-EndSection
-```

wiki/linux/x_window_system.md

@@ -0,0 +1,86 @@
+# X Window System
+
+X Window System - also called X and X11 according to the current version - is a
+protocoll for handling the display of the most unix-like operating systems.
+[Xorg](https://www.x.org/wiki/) is the most used implementation of the X
+protocoll.
+It is maintained by the [X.Org Foundation](https://x.org/wiki/).
+
+## Peripheral Devices
+
+X also handles various options of peripheral devices.
+In the files of the directory `/etc/X11/xorg.conf.d` and the file
+`/etc/X11/xorg.conf` these settings can be found.
+
+The handling of input devices is achieved by xinput.
+For this the identifier of the device to show the options of is needed.
+By running `xinput list` a list of all devices with identifiers handled by
+xinput is printed.
+Properties and options of a peripheral device can then be shown by running
+`xinput list-props <id>` where `<id>` is the identifier of the
+device.
+
+### Keyboard
+
+This section describes the handling of keyboards by X.
+
+#### Change Keyboardlayout
+
+To temporarily change the layout of the keyboard just run
+`setxkbmap <your preferred layout>`.
+For a permanent change run `localectl set-x11-keymap <your preferred layout>`.
+
+### Display
+
+This section describes the handling of displays by X.
+Additionally to the guides in this section that are independent of the used
+graphics unit special configuration for [Nvidia](/wiki/linux/nvidia.md)
+and [Intel](./intel.md) can be found in their respective entries in this wiki.
+
+#### Screen Blanking
+
+To save power the screen is set to turn black after a given amount of time.
+This can be disabled temporarily by running `xset s off` or permanently by
+adding the following lines to your `/etc/X11/xorg.conf`:
+
+```txt
+Section "ServerFlags"
+    Option "BlankTime" "0"
+EndSection
+```
+
+### Mouse
+
+This section describes the handling of mouse by X.
+
+#### Emulation of the Middle Mouse Button
+
+If middle mouse button emulation is enabled the system will emulate a middle
+mouse button click when clicking both left and right mouse button
+simultaneously.
+The middle mouse button emulation can be activated or deactivated.
+First the current options have to be confirmed as explained in
+[the peripheral section](#peripheral-devices).
+Important is the property named `libinput Middle Emulation Enabled`.
+To enable the usage of the middle mouse button it should be set to `1`.
+As written by
+[opinion_no9](https://askubuntu.com/questions/160164/how-do-i-enable-middle-mouse-button-emulation-in-12-04-lts/902976#902976)
+there are two ways to change this property.
+If the change is only needed temporarily
+`xinput set-prop <id> "libinput Middle Emulation Enabled" <flag>` can be run.
+`<id>` is the identifier of the mouse and <flag> is `0` for disabling and `1`
+for enabling the middle mouse button.
+For permanent change of the property a change or addition to
+`/etc/X11/xorg.conf.d/40-libinput.conf` can be made.
+If a section for the device is already present the line
+`Option "MiddleEmulation" "true"` should be added to it.
+Otherwise a catchall section for all types of mouses can be created like the
+following:
+
+```txt
+Section "InputClass"
+    Identifier "middle button emulation class"
+    MatchIsPointer "on"
+    Option "MiddleEmulation" "true"
+EndSection
+```