from small one page howto to huge articles all in one place
 

search text in:





Poll
What does your sytem tell when running "ulimit -u"?








poll results

Last additions:
using iotop to find disk usage hogs

using iotop to find disk usage hogs

words:

887

views:

131258

userrating:

average rating: 1.7 (87 votes) (1=very good 6=terrible)


May 25th. 2007:
Words

486

Views

238706

why adblockers are bad


Workaround and fixes for the current Core Dump Handling vulnerability affected kernels

Workaround and fixes for the current Core Dump Handling vulnerability affected kernels

words:

161

views:

119573

userrating:

average rating: 1.3 (28 votes) (1=very good 6=terrible)


April, 26th. 2006:

Druckversion
You are here: manpages





SYSFS

Section: Linux Programmer's Manual (5)
Updated: 2017-09-10
Index Return to Main Contents
 

NAME

sysfs - a filesystem for exporting kernel objects  

DESCRIPTION

The sysfs filesystem is a pseudo-filesystem which provides an interface to kernel data structures. (More precisely, the files and directories in sysfs provide a view of the kobject structures defined internally within the kernel.) The files under sysfs provide information about devices, kernel modules, filesystems, and other kernel components.

The sysfs filesystem is commonly mounted at /sys. Typically, it is mounted automatically by the system, but it can also be mounted manually using a command such as:

mount -t sysfs sysfs /sys

Many of the files in the sysfs filesystem are read-only, but some files are writable, allowing kernel variables to be changed. To avoid redundancy, symbolic links are heavily used to connect entries across the filesystem tree.  

Files and directories

The following list describes some of the files and directories under the /sys hierarchy.
/sys/block
This subdirectory contains one symbolic link for each block device that has been discovered on the system. The symbolic links point to corresponding directories under /sys/devices.
/sys/bus
This directory contains one subdirectory for each of the bus types in the kernel. Inside each of these directories are two subdirectories:
devices
This subdirectory contains symbolic links to entries in /sys/devices that correspond to the devices discovered on this bus.
drivers
This subdirectory contains one subdirectory for each device driver that is loaded on this bus.
/sys/class
This subdirectory contains a single layer of further subdirectories for each of the device classes that have been registered on the system (e.g., terminals, network devices, block devices, graphics devices, sound devices, and so on). Inside each of these subdirectories are symbolic links for each of the devices in this class. These symbolic links refer to entries in the /sys/devices directory.
/sys/dev
This directory contains two subdirectories block/ and char/, corresponding, respectively, to the block and character devices on the system. Inside each of these subdirectories are symbolic links with names of the form major-ID:minor-ID, where the ID values correspond to the major and minor ID of a specific device. Each symbolic link points to the sysfs directory for a device. The symbolic links inside /sys/dev thus provide an easy way to look up the sysfs interface using the device IDs returned by a call to stat(2) (or similar).
The following shell session shows an example from /sys/dev:
$ stat -c "%t %T" /dev/null 1 3 $ readlink /sys/dev/char/1\:3 ../../devices/virtual/mem/null $ ls -Fd /sys/devices/virtual/mem/null /sys/devices/virtual/mem/null/ $ ls -d1 /sys/devices/virtual/mem/null/* /sys/devices/virtual/mem/null/dev /sys/devices/virtual/mem/null/power/ /sys/devices/virtual/mem/null/subsystem@ /sys/devices/virtual/mem/null/uevent
/sys/devices
This is a directory that contains a filesystem representation of the kernel device tree, which is a hierarchy of device structures within the kernel.
/sys/firmware
This subdirectory contains interfaces for viewing and manipulating firmware-specific objects and attributes.
/sys/fs
This directory contains subdirectories for some filesystems. A filesystem will have a subdirectory here only if it chose to explicitly create the subdirectory.
/sys/fs/cgroup
This directory conventionally is used as a mount point for a tmpfs(5) filesystem containing mount points for cgroups(7) filesystems.
/sys/hypervisor
[To be documented]
/sys/kernel
[To be documented]
/sys/module
This subdirectory contains one subdirectory for each module that is loaded into the kernel. The name of each directory is the name of the module. In each of the subdirectories, there may be following files:
coresize
[to be documented]
initsize
[to be documented]
initstate
[to be documented]
refcnt
[to be documented]
srcversion
[to be documented]
taint
[to be documented]
uevent
[to be documented]
version
[to be documented]
In each of the subdirectories, there may be following subdirectories:
drivers
[To be documented]
holders
[To be documented]
notes
[To be documented]
parameters
This directory contains one file for each module parameter, with each file containing the value of the corresponding parameter. Some of these files are writable, allowing the
sections
This subdirectories contains files with information about module sections. This information is mainly used for debugging.
[To be documented]
/sys/power
[To be documented]
 

VERSIONS

The sysfs filesystem first appeared in Linux 2.6.0.  

CONFORMING TO

The sysfs filesystem is Linux-specific.  

NOTES

This manual page is incomplete, possibly inaccurate, and is the kind of thing that needs to be updated very often.  

SEE ALSO

proc(5), udev(7)

P. Mochel. (2005). The sysfs filesystem. Proceedings of the 2005 Ottawa Linux Symposium.

The kernel source file Documentation/filesystems/sysfs.txt and various other files in Documentation/ABI and Documentation/*/sysfs.txt  

COLOPHON

This page is part of release 4.13 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.


 

Index

NAME
DESCRIPTION
Files and directories
VERSIONS
CONFORMING TO
NOTES
SEE ALSO
COLOPHON





Other free services
toURL.org
Shorten long
URLs to short
links like
http://tourl.org/2
tourl.org
.
Reverse DNS lookup
Find out which hostname(s)
resolve to a
given IP or other hostnames for the server
www.reversednslookup.org
rdf newsfeed | rss newsfeed | Atom newsfeed
- Powered by LeopardCMS - Running on Gentoo -
Copyright 2004-2018 Sascha Nitsch Unternehmensberatung UG(haftungsbeschränkt)
Valid XHTML1.1 : Valid CSS : buttonmaker
- Level Triple-A Conformance to Web Content Accessibility Guidelines 1.0 -
- Copyright and legal notices -
Time to create this page: 3.4 ms