I already have a Windows app that allows the user to browse a directory full of voice recordings (wav, mp3).
The user can set filters in order to display, let’s say, just yesterday recordings of agent John.
If the user clicks on one line of that listing I want to play the file.
and I presume that you want to use Audacity as the “playback engine”.
To launch Audacity and load the audio file:
“fully-qualified-file-name” means, the file name including the full file path.
There is no built-in command-line option to start playback, but you could perhaps programmatically generate a spacebar keyboard event (after allowing a suitable pause to allow Audacity to launch and load the file).