The /proc directory contains special "files" that
either extract information from or send information to the
kernel.
However, the /proc directory is much more powerful
than you might initially think. Through the various "files" in this directory
(which are really not files at all but interfaces into the kernel), a
system administrator can use /proc as an easy method of
accessing information about the state of the kernel, the attributes of
the machine, the states of individual processes, and more. By using
cat in combination with the interfaces within
/proc, you can immediately access an enormous
amount of information about any system. As an example, if you want
to see how the memory registers are currently assigned on your computer:
[truk@tictactoe /proc]$ cat iomem
00000000-0009fbff : System RAM
0009fc00-0009ffff : reserved
000a0000-000bffff : Video RAM area
000c0000-000c7fff : Video ROM
000f0000-000fffff : System ROM
00100000-07ffffff : System RAM
00100000-002553d7 : Kernel code
002553d8-0026d91b : Kernel data
e0000000-e3ffffff : VIA Technologies, Inc. VT82C597 [Apollo VP3]
e4000000-e7ffffff : PCI Bus #01
e4000000-e4003fff : Matrox Graphics, Inc. MGA G200 AGP
e5000000-e57fffff : Matrox Graphics, Inc. MGA G200 AGP
e8000000-e8ffffff : PCI Bus #01
e8000000-e8ffffff : Matrox Graphics, Inc. MGA G200 AGP
ea000000-ea00007f : Digital Equipment Corporation DECchip 21140
ea000000-ea00007f : eth0
ffff0000-ffffffff : reserved
[truk@tictactoe /proc]$ |
Or (and more usefully), if were connecting to an unknown machine and
wanted to know its CPU type and speed, you can use the following
command:
Other valuable bits of system information can be gathered from
cmdline, meminfo,
partitions, and version, among
others.
The directories in /proc symbolize a
collection of information about a particular application or process. For
example, the /proc/sys/kernel directory is full of
information about the kernel, such as the maximum number of threads
(threads-max) and the maximum number of messages (msgmax).
