Actually I was not going to ask that question because I read in fact the whole UAVCAN v1 crash course entry where this aspect is mentioned 
But yes, I fully admit guilty to the trial-and-error approach when it comes to reading documentation 
Actually I’ve got a couple of suggestions to make the CLI tool easier to use.
- As a user using the
pyuavcan publishfeature I’m interested first and foremost in publishing UAVCAN data on various transport layers. That’s why my focus is on setting up the message and not configuring the transportlayer which additionally is appended at the end of a already very long bash entry (alternatively it’s in front but the manipulation of the message is at the end, also undesirable). This is actually the reason why I was unable to make the connection of the 59 node id with the 59 at the end of the --tr string - it was simply lost to my eye focus because of the awful long bash line. - As a typical user I’m not going to change my transport layer 3 times a day. Probably I’ll change it never. Therefore it might be worth considering to introduce “state” to the pyuavcan CLI tool which allows to permanently configure the desired transport layer. (pyuavcan config --gobal transport=CAN). It’s probably only you as the UAVCAN devs that need to change between various transport layers on a regular basis.
- The transport layer configuration is done via a string. I daresay that’s unusal for the typical bash user. They(we) are used to having identifiers before the parameter which give some hint as what it is that we are configuring. E.g.
--tr=[CAN|Serial|...]
--tr=CAN [can0|vcan0|can1|...] -can-mtu-=[8|64] -can-id=(0-127)