Chapter 2. The

proc

File System

37

2.2.28.

/proc/swaps

This file measures swap space and its utilization. For a system with only one swap partition, the output

of

/proc/swap

may look similar to this:

Filename

Type

Size

Used

Priority

/dev/hda6

partition

136512

20024

 1

While some of this information can be found in other files in the

/proc/

directory,

/proc/swap

provides a snapshot of every swap filename, type of swap space, the total size, and the amount of this

space that is in use (in kilobytes). The priority column is useful when multiple swap files are in use.

The lower the priority, the more likely the swap file is to be used.

2.2.29.

/proc/uptime

This file contains information about how long the system has on since its last restart. The output of

/proc/uptime

is quite minimal:

350735.47 234388.90

The first number tells you the total number of seconds the system has been up. The second number

tells you how much of that time the machine has spent idle in seconds.

2.2.30.

/proc/version

This files tells you the versions of the Linux kernel and

gcc

, as well as the version of Red Hat Linux

installed on the system:

Linux version 2.4.18 0.40 (user@foo.redhat.com)(gcc version 2.96 20000731

(Red Hat Linux 7.2 2.96 102)) #1 Tue May 28 04:28:05 EDT 2002

This information is used for a variety of purposes, including the version data presented when a user

logs in.

2.3. Directories in

/proc/

Common groups of information concerning the kernel are grouped into directories and subdirectories

within the

/proc/

directory.

2.3.1. Process Directories

Every

/proc/

directory contains a number of directories numerical names. A listing of them may

start off like this:

dr xr xr x

3 root

root

0 Feb 13 01:28 1

dr xr xr x

3 root

root

0 Feb 13 01:28 1010

dr xr xr x

3 xfs

xfs

0 Feb 13 01:28 1087

dr xr xr x

3 daemon

daemon

0 Feb 13 01:28 1123

dr xr xr x

3 root

root

0 Feb 13 01:28 11307

dr xr xr x

3 apache

apache

0 Feb 13 01:28 13660

dr xr xr x

3 rpc

rpc

0 Feb 13 01:28 637

dr xr xr x

3 rpcuser

rpcuser

0 Feb 13 01:28 666