[LAU] Scripting jackd connections

Len Ovens len at ovenwerks.net
Wed Jun 15 21:18:38 UTC 2016

On Wed, 15 Jun 2016, worik wrote:

> Apologies if this has been asked and answered already but I can find no
> solutns.

It is a missing part of the puzzle for sure.

> My jackd set up is quite idiosyncratic.  When I plug in my external
> sound gear I have to change the connections each time to get sound out.
> I also use a variety of gear from the same computer each with its own
> requirements.
> I would like to be able to write a script that would start up jackd, set
> the default sound IO to use jackd (I am on Ubuntu Studio) start a couple
> of other applications and change the connections.

You probably really want to use jackdbus (what qjackctl on UbuntuSTudio 
uses by default) so that you can change the system device the jack server 
uses on the fly. See:
http://gareus.org/blog/jack2dbus for the best recipe I have seen for 
detecting that a USB audio IF has been plugged in and switching jack over 
to it.

> The man page for jackd is not much help.  I have found some pages that
> have part of the answer (e.., http://www.64studio.com/node/740) but
> surely there is some direct way of manipulating jackd connections
> without a mouse and GUI?

jack_connect and jack_disconnect? They would not be in the jackd manpage 
because they are separate applications. (jack_control which you will 
probably use in your script to change things has no man page :)  just run 
jack_control with no parameters for the help and play with the parameters 
that seem to want to tell you info about how things are now)

Len Ovens

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