How to terminate screen terminal sessions cleanly on macOS
So how do you communicate with a serial device that is connected to your Mac?
In this situation, you can use the screen command on your Mac to do so.
After you terminate the serial session with Ctrl+A+D, you may find that the serial device is still being hogged by the screen command.
When you try to access the device again, you may encounter a Resource busy error message.
For example, after I detached my screen terminal from /dev/cu.SLAB_USBtoUART, I will get the following message if I try to connect to the same device again:
Cannot open line '/dev/cu.SLAB_USBtoUART' for R/W: Resource busy
Given these points, this post shows how we can terminate screen terminal sessions cleanly on macOS.
Steps to terminate screen terminal sessions cleanly on macOS
In order to create the situation of resource hogging, let's connect your serial device with the screen command. For example, I may connect to my ESPx device with the following command:
screen -port /dev/cu.SLAB_USBtoUART 115200
After doing so, detach the session by pressing Ctrl+A+D.
When you do so, the serial device is still being locked by the screen command.
Given that, let's list the screens that are being locked with the following command:
After the command completes, you should see something like this the following as an output:
There is a screen on: 10184.ttys001.ZZZM56582454A (Detached) 1 Socket in /var/folders/vs/lx78cw0x7m921p6qdmw9h4xm0000gr/T/.screen.
In order to terminate the screen terminal cleanly, run the following command:
screen -X -S 10184 quit
After the command completes, you can run the screen command to verify if the session had been terminated:
When the previous terminal session had been terminated successfully, you should see the following output:
No Sockets found in /var/folders/vs/lx78cw0x7m921p6qdmw9h4xm0000gr/T/.screen.