4. sysfs

Sysfs was created long ago to better manage devices on our system that the /dev directory failed to do. Sysfs is a virtual filesystem, most often mounted to the /sys directory. It gives us more detailed information than what we would be able to see in the /dev directory. Both directories /sys and /dev seem to be very similar and they are in some regards, but they do have major differences. Basically, the /dev directory is simple, it allows other programs to access devices themselves, while the /sys filesystem is used to view information and manage the device.

The /sys filesystem basically contains all the information for all devices on your system, such as the manufacturer and model, where the device is plugged in, the state of the device, the hierarchy of devices and more. The files you see here aren't device nodes, so you don't really interact with devices from the /sys directory, rather you are managing devices.

Take a look at the contents of the /sys directory:

pete@icebox:~$ ls /sys/block/sda
alignment_offset discard_alignment holders removable sda6 trace
bdi events inflight ro size uevent
capability events_async power sda1 slaves
dev events_poll_msecs queue sda2 stat
device ext_range range sda5 subsystem


Check out the contents of the /sys directory and see what files are located in there.


What directory is used to view detailed information on devices?