What is Sysfs (/sys)?

Sysfs (/sys) provides a structured view of the device model and kernel objects. Unlike /proc which evolved organically, /sys was designed with a clean hierarchy: /sys/class/ groups devices by type (network, block, input), /sys/bus/ organizes by bus type (PCI, USB, SCSI), /sys/devices/ shows the physical device tree, and /sys/module/ lists loaded kernel modules with their parameters. Sysfs enables device management from userspace — for example, changing LED brightness by writing to /sys/class/leds/*/brightness. The udev device manager uses sysfs information to create device nodes in /dev dynamically.