Question

9

How do I make udev rules work?

rated 0 times [ 9] [ 0] / answers: 1 / hits: 30981 / 3 Years ago, fri, october 22, 2021, 7:30:42

I would like to learn udev rules. Here is what I do:

victor@X301A1:~$ ls /etc/udev/rules.d/

70-persistent-cd.rules  70-persistent-net.rules  README

Then:

victor@X301A1:~$ sudo gedit /etc/udev/rules.d/01-my-first-udev.rules

My rule:

ACTION=="add", RUN+="echo HELLO ! > /home/victor/udev_test_log.txt"

After saving the file:

 sudo udevadm control --reload-rules

I expected that connecting an USB device would write in the file but nothing happens.
Where am I wrong?

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doredtness

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4 Years ago

answered 3 Years ago inglehare · Accepted Answer

In RUN you must to put a path to a script. See man udev:

Add a program to the list of programs to be executed for a specific
device. This can only be used for very short running tasks. Running
an event process for a long period of time may block all further
events for this or a dependent device. Long running tasks need to
be immediately detached from the event process itself.

For examle, create a new script, let say hello.sh in /lib/udev with sudo -H gedit /lib/udev/hello.sh and put next lines inside:

#!/bin/bash



echo HELLO ! > /home/<username>/udev_test_log.txt

Change <username> with your user name. Save the file, close it and make it executable with:

chmod +x /lib/udev/hello.sh

Add a new rule in your /etc/udev/rules.d/01-my-first-udev.rules file like this:

ACTION=="add", RUN+="/lib/udev/hello.sh"