In terms of content, what is the difference between these 4 folders?
/dev/usb
/proc/bus/usb
/sys/bus/usb
/sys/class/usb_device
I found many symlinks between those folders, many redundant information. More generically what is the idea/purpose in the first place of each of these folders?
Best Answer
Take from the wikipedia:
/dev Essential devices, e.g., /dev/null.
/proc Virtual filesystem documenting kernel and process status as text files, e.g., uptime, network. In Linux, corresponds to a procfs mount.
/sys Modern Linux distributions include a /sys directory as a virtual filesystem (sysfs, comparable to /proc, which is a procfs), which stores and allows modification of the devices connected to the system, whereas many traditional UNIX and Unix-like operating systems use /sys as a symbolic link to the kernel source tree