The /proc filesystem

The /proc  filesystem contains a illusionary filesystem. It does not exist on a disk. Instead, the kernel creates it in memory. It is used to provide information about the system (originally about processes, hence the name). Some of the more important files and directories are explained below. The /proc  filesystem is described in more detail in the proc  manual page.

/proc/1 

A directory with information about process number 1. Each process has a directory below /proc  with the name being its process identification number.

/proc/cpuinfo 

Information about the processor, such as its type, make, model, and perfomance.

/proc/devices 

List of device drivers configured into the currently running kernel.

/proc/dma 

Shows which DMA channels are being used at the moment.

/proc/filesystems 

Filesystems configured into the kernel.

/proc/interrupts 

Shows which interrupts are in use, and how many of each there have been.

/proc/ioports 

Which I/O ports are in use at the moment.

/proc/kcore 

An image of the physical memory of the system. This is exactly the same size as your physical memory, but does not really take up that much memory; it is generated on the fly as programs access it. (Remember: unless you copy it elsewhere, nothing under /proc  takes up any disk space at all.)

/proc/kmsg 

Messages output by the kernel. These are also routed to syslog .

/proc/ksyms 

Symbol table for the kernel.

/proc/loadavg 

The `load average' of the system; three meaningless indicators of how much work the system has to do at the moment.

/proc/meminfo 

Information about memory usage, both physical and swap.

/proc/modules 

Which kernel modules are loaded at the moment.

/proc/net 

Status information about network protocols.

/proc/self 

A symbolic link to the process directory of the program that is looking at /proc . When two processes look at /proc , they get different links. This is mainly a convenience to make it easier for programs to get at their process directory.

/proc/stat 

Various statistics about the system, such as the number of page faults since the system was booted.

/proc/uptime 

The time the system has been up.

/proc/version 

The kernel version.