In which log should I check for udev errors?

Question

I've written a udev rule which is run each time my device is mounted/dismounted.

However, in which Linux (Debian) error log should I check when debugging such rules?

Answer 1

You can change logging priority to "info" level or even "debug" by:

udevadm control --log-priority=info

Then you will see all logs in your system log.

When you are done, bring it to default "err". See in /etc/udev/udev.conf what is your default logging level.

Answer 2

unbuffer udevadm monitor --environment The use of unbuffer is optional, but when piping output to grep saves you a headache. By default output is buffered in 4k blocks, nothing will be printed until that buffer is full.

You didn't forget to reload the rules? sudo udevadm control --reload