audio: added and linked playerctl and sxhkd

wiki/audio.md

@@ -8,6 +8,8 @@ Music and Audiobooks can be obtained by buying the digital files or by
 [extracting them off of a CD](#extract-audio-files-from-cds).
 Podcasts need a so called Podcatcher.
 A Podcatcher is used to subscribe to podcasts and download them automatically.
+For Linux specific music software navigate to the corresponding
+[wiki entry](/wiki/linux/audio.md).
 
 ## Media Software
 
@@ -17,6 +19,9 @@ There are differences depending on your preffered software interface.
 
 ### Software for Music/Podcasts/Audiobooks
 
+The following is a list of server software, that is featured in this wiki.
+The corresponding client software is handled in the server softwares wiki entry.
+
 - [Subsonic](./subsonic.md) is a media streamer for music, podcasts and
   audiobooks.
   Subsonic is self-hostable.

wiki/linux/audio.md

@@ -1,6 +1,8 @@
 # Audio
 
 Audio is an important point in a linux desktop environment
+For non-Linux specific audio software navigate to the corresponding
+[wiki article](/wiki/audio.md).
 
 ## Sound Server
 
@@ -23,3 +25,12 @@ 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.
+
+## Control Audio from Command Line/by Hotkey
+
+Audio from many different clients can be controlled (started, stopped, skipped)
+using the command line with [PlayerCTL](/wiki/linux/playerctl.md).
+With additional software it can also be used to control audio/music by pressing
+hotkeys.
+This is explained in the
+[PlayerCTL entry](/wiki/linux/playerctl.md#using-hotkeys).

wiki/linux/playerctl.md

@@ -0,0 +1,37 @@
+# PlayerCTL
+
+[PlayerCTL](https://github.com/altdesktop/playerctl) is a MPRIS (Media Player
+Remote Interfacing Specification) [media player](/wiki/audio.md#media-software)
+command-line controller for Spotify, [Sonixd](/wiki/subsonic.md#client), MPV and
+many other different media clients aswell as [browser](/wiki/browser.md).
+
+## Setup
+
+On most linux distributions PlayerCTL can be installed with the `playerctl`
+package.
+Alternatively it can be installed via
+[Github](https://github.com/altdesktop/playerctl).
+
+## Usage
+
+## Basic Commands
+
+For starting, stopping the music the commans are simple and very intuitive.
+The following commands show how to control music.
+The commands are quite self-explaining.
+
+```sh
+playerctl play
+playerctl pause
+playerctl play-pause
+playerctl stop
+playerctl next
+playerctl previous
+```
+
+## Using Hotkeys
+
+Hotkeys can be more accessible than typing the commands to start or stop music
+in the terminal.
+With [SXHKD](/wiki/linux/sxhkd.md#setting-a-hotkey) commands from the CLI can
+be set to a hotkey.

wiki/linux/sxhkd.md

@@ -0,0 +1,43 @@
+# SXHKD
+
+[SXHKD](https://github.com/baskerville/sxhkd) - short for Simple
+[X](/wiki/linux/x_window_system.md) hotkey daemon - is a program to set hotkeys.
+
+## Setup
+
+On most linux distributions SXHKD can be installed with the `sxhkd`
+package.
+Alternatively it can be installed via
+[Github](https://github.com/baskerville/sxhkd).
+
+## Usage
+
+### Setting a Hotkey
+
+Configuration for setting hotkeys is done in the file `~/.config/sxhkd/sxhkdrc`.
+A hotkey corresponds to typically two, sometimes more lines within this
+configuration file.
+The first line describes the keys that act as hotkeys and the second line
+describes the commands that are run on pressing the hotkey.
+
+There are simple hotkeys using only one key (in this case the Launch Button).
+
+```txt
+XF86LaunchB
+	xdotool selectwindow | xsel -bi
+```
+
+And some commands use modifier keys or multiple keys.
+
+```txt
+super + shift + equal
+	sxiv -rt "$HOME/image"
+```
+
+When using similar commands it can be useful to map multiple hotkeys in one
+entry.
+
+```txt
+super + {_,shift + }{h,j,k,l}
+	bspc node -{f,s} {west,south,north,east}
+```