whatis udev
udev
Also known as: udev rules, systemd-udevd
The device manager that reacts to hardware events, creates /dev nodes, loads drivers, and applies custom rules for naming and permissions.
What Is udev in Linux?
When you plug in a device, the kernel emits an event and udev matches it against rules in /usr/lib/udev/rules.d/ and /etc/udev/rules.d/. Rules can set permissions, create stable symlinks, rename network interfaces, or run a command.
udevadm monitor shows events live and udevadm info prints the attributes you can match on.
Example
udevadm info --query=all --name=/dev/sdbLearn more about udev
- udev Rules Explained: Making Devices Behave the Way You Want Device names are not stable, permissions default to root, and nothing happens automatically when you plug something in unless you tell it to. udev rules fix all three.