joerg-krause writes
Add an onvolumechange config option. This option can be set in the configuration file to run a command or script when the volume is changed. The command or script will be called with the volume as the first argument.
A use case for this might be to display the new volume level on a LCD display connected to the media renderer.
Note that the full path for the command or script has to be specified, e.g. /usr/bin/logger. Executable shell scripts must begin with a shebang, e.g. #!/bin/sh.