I am trying to execute commands using the -X switch on the Spike Prime Hub but all I get is either nothing, or unknown command errors. Here is what I tried so far:

screen /dev/ttyACM0 -X 'print("test")' screen /dev/ttyACM0 -X $'print("test")/n' screen /dev/ttyACM0 | 'print("test")' screen /dev/ttyACM0 | $'print("test")/n'

The piped commands gave me unknown command errors. When I change the main.py and add some prints, they are shown even if printed before I login. So stream wise that is working no matter when I login.

Another issue occures with the rshell rsync. I had to add a switch to stop the sound files from syncing since they crash rshell. Also rshell stops the code execution on the hub. I tried the above commands before and after rshell rsync call. When I login the hub after rshell I can enter python commands without hitting ctrl+c. Before rsync I have to stop execution with ctrl+c before I am able to type.

But the screen command does not execute python in all cases. Any ideas ?

The main task I want to achieve is that the hub continues execution after rsync. I wanted that with a screen command. But the whole Spike Prime software seems buggy and sluggish from the open source point of view.

1 Answer 1


With the prime hub you need to exit the hub default process before you can send commands using ctrl-c.

Ctrl-c is the character 0x03.

This is my python script that I use to send micropython scripts over to my hub: https://github.com/gpdaniels/spike-prime/blob/master/simulator/run.py

It has lots of nastyness in it like this:


To try and get the hub to stop the running script and behave.

Also there's functions to read the serial input from the hub until it sees the >>> characters which indicate the REPL is ready to receive python commands.

  • 1
    Wouldn't it be easier to send the script file in a whole with rsync and force the hub to execute it by calling execfile() ? That might be faster because you call sleep(0.1) between every command. Anyway your script is a big help, thanks man.
    – areop-enap
    Commented Jan 1, 2021 at 22:06
  • The sleeps in my script are just to get the REPL into a good state. I send the whole script using the paste mode of the REPL. After which it is executed in one go.
    – gpdaniels
    Commented Jan 8, 2021 at 10:51
  • Well, sounds good, but isn't the readline of python reading a file line by line ? Later you pass the file line by line to write_command(...) which then waits for every line 0.2 seconds. Not sure if that might be slow thou, I have to get into the code for a bit longer to clearly understand...
    – areop-enap
    Commented Jan 9, 2021 at 16:31
  • Yeah there is a lot of delays, rather than spending time on my dodgy code, I'd recommend rshell [ github.com/dhylands/rshell ] which is great!
    – gpdaniels
    Commented Jan 11, 2021 at 12:03
  • I found that repository already but I didn't know it can execute code on the hub. It's in the pyboard.py file. I still have to figure out how it works but accordingly to the header it shouldn't be that hard. Thanks for your help. Btw I tried to use your run.py to paste a larger code file in one big chunk but it fails after some lines. Seemingly the REPL paste mode cant handle big chunks. I used rsync to copy files to the board already before but wanted copy and execute at once.
    – areop-enap
    Commented Jan 11, 2021 at 21:39

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