cant execute commands on running linux

Harald Seiler hws at
Tue Aug 30 12:46:27 CEST 2022

Hi Maik,

On Tue, 2022-08-30 at 12:12 +0200, Maik Nassauer wrote:
> Hey all :)
> Thank you very much for tbot, its a realy nice tool <3

Glad you like it :)

> I cant figure out how to execute commands on the running linux system. I 
> have to powercycle/reboot the system to get my commands running, because 
> the LinuxBootLogin is checking for a complete bootup?

This is correct, `LinuxBootLogin` waits for the board to boot and then
logs in once the login prompt shows up.  In general, tbot is usually
used in such a setup where the board is freshly booted at the start of a
test-run.  Ideally, your board config (`MyBoard` class) should use the
`board.PowerControl` initializer to automatically control board power.

That said, you can also use tbot in an environment where the board is
always running.  In that case, you should leave the board at the shell
prompt and use a Linux configuration like this:

	class MyBoardLinux(board.Connector, linux.Bash):

With this config, tbot will assume that the board is already running and
waiting at a shell prompt.  Of course this means you have to prepare the
board beforehand if it wasn't already on.

While this is possible, in most cases, I have found it to be better to
stick to the powercycling approach.  The reason is that little
inconsistencies caused by the board staying on will be a pain when
debugging hard problems.  If you automate powercontrol with a switchable
power outlet, the entire test-run is hands-off.  Then you can focus on
doing something else while tbot is running, which makes it much less
annoying to have to wait for the board to boot each time.

But I know this heavily depends on the kind of work you do.  If you are
mostly working on userspace applications, I understand that it might be
much more favorable to keep the board powered on at all times. If that's
your usecase, I can prepare a full config with a testcase to
automatically boot once and then keeping the board powered on for you.
I have some scripts locally which do this but I'll have to clean them
first before I can show them here...


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