The /proc/ directory is a virtual filesystem that provides a view of the kernel’s data structures and parameters. It contains information about processes, hardware, memory, modules, and other aspects of the system. The files in /proc/ are not stored on disk, but are generated on the fly by the kernel when they are accessed. Therefore, any changes to files in /proc/ are immediately recognized by the kernel and affect its behavior. For example, writing a value to /proc/sys/kernel/hostname will change the system’s hostname without rebooting. The files in /proc/ are not all read-only; some of them can be modified by the root user or by processes with the appropriate permissions. The files in /proc/ are readable by any user, unless restricted by the kernel or by the mount options. References: LPI Linux Essentials - 1.101.2, LPI Linux Administrator - 102.3