The /proc Filesystem

The /proc Filesystem
Certain filesystems, like the one mounted at /proc, are called pseudo-filesystems because they have no actual permanent presence anywhere on the disk.

The /proc filesystem contains virtual files (files that exist only in memory) that permit viewing constantly changing kernel data. /proc contains files and directories that mimic kernel structures and configuration information. It does not contain real files, but runtime system information, e.g. system memory, devices mounted, hardware configuration, etc. Some important entries in /proc are:

/proc/cpuinfo
/proc/interrupts
/proc/meminfo
/proc/mounts
/proc/partitions
/proc/version

/proc has subdirectories as well, including:

/proc/
/proc/sys

The first example shows there is a directory for every process running on the system, which contains vital information about it. The second example shows a virtual directory that contains a lot of information about the entire system, in particular its hardware and configuration. The /proc filesystem is very useful because the information it reports is gathered only as needed and never needs storage on the disk.