Edition 20.0.1
Abstract
Mono-spaced Bold
To see the contents of the filemy_next_bestselling_novel
in your current working directory, enter thecat my_next_bestselling_novel
command at the shell prompt and press Enter to execute the command.
Press Enter to execute the command.Press Ctrl+Alt+F2 to switch to a virtual terminal.
mono-spaced bold
. For example:
File-related classes includefilesystem
for file systems,file
for files, anddir
for directories. Each class has its own associated set of permissions.
Choose Mouse Preferences. In the Buttons tab, select the Left-handed mouse check box and click to switch the primary mouse button from the left to the right (making the mouse suitable for use in the left hand).→ → from the main menu bar to launchTo insert a special character into a gedit file, choose → → from the main menu bar. Next, choose → from the Character Map menu bar, type the name of the character in the Search field and click . The character you sought will be highlighted in the Character Table. Double-click this highlighted character to place it in the Text to copy field and then click the button. Now switch back to your document and choose → from the gedit menu bar.
Mono-spaced Bold Italic
or Proportional Bold Italic
To connect to a remote machine using ssh, typessh username@domain.name
at a shell prompt. If the remote machine isexample.com
and your username on that machine is john, typessh john@example.com
.Themount -o remount file-system
command remounts the named file system. For example, to remount the/home
file system, the command ismount -o remount /home
.To see the version of a currently installed package, use therpm -q package
command. It will return a result as follows:package-version-release
.
Publican is a DocBook publishing system.
mono-spaced roman
and presented thus:
books Desktop documentation drafts mss photos stuff svn books_tests Desktop1 downloads images notes scripts svgs
mono-spaced roman
but add syntax highlighting as follows:
package org.jboss.book.jca.ex1;
import javax.naming.InitialContext;
public class ExClient
{
public static void main(String args[])
throws Exception
{
InitialContext iniCtx = new InitialContext();
Object ref = iniCtx.lookup("EchoBean");
EchoHome home = (EchoHome) ref;
Echo echo = home.create();
System.out.println("Created Echo");
System.out.println("Echo.echo('Hello') = " + echo.echo("Hello"));
}
}
Note
Important
Warning
Fedora Documentation
and the component system-administrator's-reference-guide
. The following link automatically loads this information for you: http://bugzilla.redhat.com/.
Summary
field.
Description
field and give us the details of the error or suggestion as specifically as you can. If possible, include some surrounding text so we know where the error occurs or the suggestion fits.
Document URL: Section number and name: Error or suggestion: Additional information:
/etc/sysconfig/network-scripts/
directory. The scripts used to activate and deactivate these network interfaces are also located here. Although the number and type of interface files can differ from system to system, there are three categories of files that exist in this directory:
/etc/hosts
DNS
server. Regardless of the type of network the computer is on, this file should contain a line specifying the IP
address of the loopback device (127.0.0.1
) as localhost.localdomain
. For more information, see the hosts(5)
man page.
/etc/hostname
hostname(5)
and man hostnamectl(1)
.
/etc/resolv.conf
IP
addresses of DNS
servers and the search domain. Unless configured to do otherwise, the network initialization scripts populate this file. For more information about this file, refer to the resolv.conf(5)
man page.
/etc/sysconfig/network
/etc/sysconfig/network-scripts/ifcfg-interface-name
Network interface names
ifcfg-name
, where name refers to the name of the device that the configuration file controls.
/etc/sysconfig/network-scripts/ifcfg-eth0
, which controls the first Ethernet network interface card or NIC in the system. In a system with multiple NICs, there are multiple ifcfg-ethX
files (where X is a unique number corresponding to a specific interface). Because each device has its own configuration file, an administrator can control how each interface functions individually.
ifcfg-eth0
file for a system using a fixed IP
address:
DEVICE=eth0 BOOTPROTO=none ONBOOT=yes NETMASK=255.255.255.0 IPADDR=10.0.1.27 USERCTL=no
ifcfg-eth0
file for an interface using DHCP
looks different because IP
information is provided by the DHCP
server:
DEVICE=eth0 BOOTPROTO=dhcp ONBOOT=yes
BONDING_OPTS
=parameters /etc/sysconfig/network-scripts/ifcfg-bondN
. These parameters are identical to those used for bonding devices in /sys/class/net/bonding_device/bonding
, and the module parameters for the bonding driver as described in bonding
Module Directives.
BONDING_OPTS
directive in ifcfg-name
. Do not specify options for the bonding device in /etc/modprobe.d/bonding.conf
, or in the deprecated /etc/modprobe.conf
file.
BOOTPROTO
=protocol none
— No boot-time protocol should be used.
bootp
— The BOOTP
protocol should be used.
dhcp
— The DHCP
protocol should be used.
BROADCAST
=addressipcalc
.
DEVICE
=name PPP
devices where it is the logical name).
DHCP_HOSTNAME
=nameDHCP
server. Use this option only if the DHCP
server requires the client to specify a host name before receiving an IP
address.
DHCPV6C
=answeryes
— Use DHCP
to obtain an IPv6
address for this interface.
no
— Do not use DHCP
to obtain an IPv6
address for this interface. This is the default value.
IPv6
link-local address will still be assigned by default. The link-local address is based on the MAC address of the interface as per RFC 4862.
DHCPV6C_OPTIONS
=answer-P
— Enable IPv6
prefix delegation.
-S
— Use DHCP
to obtain stateless configuration only, not addresses, for this interface.
-N
— Restore normal operation after using the -T
or -P
options.
-T
— Use DHCP
to obtain a temporary IPv6
address for this interface.
-D
— Override the default when selecting the type of DHCP Unique Identifier (DUID) to use.
DHCPv6
client (dhclient) creates a DHCP Unique Identifier (DUID) based on the link-layer address (DUID-LL) if it is running in stateless mode (with the -S
option, to not request an address), or it creates an identifier based on the link-layer address plus a timestamp (DUID-LLT) if it is running in stateful mode (without -S
, requesting an address). The -D
option overrides this default, with a value of either LL
or LLT
.
DNS{1,2}
=address/etc/resolv.conf
if the PEERDNS
directive is set to yes
.
ETHTOOL_OPTS
=options ethtool
. For example, if you wanted to force 100Mb, full duplex:
ETHTOOL_OPTS="autoneg off speed 100 duplex full"
ETHTOOL_OPTS
to set the interface speed and duplex settings. Custom initscripts run outside of the network init script lead to unpredictable results during a post-boot network service restart.
Set “autoneg off” before changing speed or duplex settings
autoneg off
option. This option needs to be stated first, as the option entries are order-dependent.
GATEWAY
=addressIP
address of the network router or gateway device (if any). Note that if this option is present in an interface configuration file it will take precedence over the GATEWAY
option in the /etc/sysconfig/network
file. It is therefore recommended that you chose between setting this option for global effect in /etc/sysconfig/network
or per-interface.
HOTPLUG
=answeryes
— This device should be activated when it is hot-plugged (this is the default option).
no
— This device should not be activated when it is hot-plugged.
HOTPLUG=no
option can be used to prevent a channel bonding interface from being activated when a bonding kernel module is loaded.
HWADDR
=MAC-address MACADDR
. See the Fedora Networking Guide for more information on device naming.
IPADDR
=address IPv4
address.
IPV6ADDR
=address IPv6
address on an interface.
/64
is assumed. Note that this setting depends on IPV6INIT
being enabled.
IPV6ADDR_SECONDARIES
=address IPv6
addresses.
/64
is assumed. Note that this setting depends on IPV6INIT
being enabled.
IPV6INIT
=answer yes
— Initialize this interface for IPv6
addressing.
no
— Do not initialize this interface for IPv6
addressing. This is the default value.
IPv6
static and DHCP
assignment of IPv6
addresses. It does not affect IPv6 Stateless Address Autoconfiguration (SLAAC) as per RFC 4862.
IPv6
.
IPV6_AUTOCONF
=answer yes
— Enable IPv6
autoconf configuration for this interface.
no
— Disable IPv6
autoconf configuration for this interface.
IPv6
address will be requested using Neighbor Discovery (ND) from a router running the radvd
daemon.
IPV6_AUTOCONF
depends on IPV6FORWARDING
as follows:
IPV6FORWARDING
=yes
, then IPV6_AUTOCONF
will default to no
.
IPV6FORWARDING
=no
, then IPV6_AUTOCONF
will default to yes
and IPV6_ROUTER
has no effect.
IPV6_MTU
=value IPV6_PRIVACY
=rfc3041 IPV6INIT
option being enabled.
EUI-64
method. The address is appended to a prefix but as the address is normally derived from the MAC address it is globally unique even when the prefix changes. In the case of a link-local address the prefix is fe80::/64
as per RFC 2462 IPv6 Stateless Address Autoconfiguration.
LINKDELAY
=time MACADDR
=MAC-address HWADDR
directive.
MASTER
=bond-interface SLAVE
directive.
NETMASK
=mask NETWORK
=address ipcalc
.
NM_CONTROLLED
=answer yes
— NetworkManager is permitted to configure this device. This is the default behavior and can be omitted.
no
— NetworkManager is not permitted to configure this device.
Note
NM_CONTROLLED
directive is dependent on the NM_BOND_VLAN_ENABLED
directive in /etc/sysconfig/network
. If and only if that directive is present and is one of yes
, y
, or true
, will NetworkManager detect and manage bonding and VLAN interfaces.
NOZEROCONF
=answeryes
— Do not set a route for dynamic IPv6
link-local addresses.
no
— Allow setting a route for dynamic IPv6
link-local addresses.
ONBOOT
=answeryes
— This device should be activated at boot-time.
no
— This device should not be activated at boot-time.
PEERDNS
=answeryes
— Modify /etc/resolv.conf
if the DNS
directive is set. If using DHCP
, then yes
is the default.
no
— Do not modify /etc/resolv.conf
.
SLAVE
=answeryes
— This device is controlled by the channel bonding interface specified in the MASTER
directive.
no
— This device is not controlled by the channel bonding interface specified in the MASTER
directive.
MASTER
directive.
SRCADDR
=address IP
address for outgoing packets.
USERCTL
=answer yes
— Non-root
users are allowed to control this device.
no
— Non-root
users are not allowed to control this device.
SUBCHANNELS=<read_device_bus_id>, <write_device_bus_id>, <data_device_bus_id>
PORTNAME=myname;
CTCPROT
=answer 0
— Compatibility mode, TCP/IP for Virtual Machines (used with non-Linux peers other than IBM S/390 and IBM System z operating systems). This is the default mode.
1
— Extended mode, used for Linux-to-Linux Peers.
3
— Compatibility mode for S/390 and IBM System z operating systems.
OPTION
='answer'OPTIONS='layer2=1 portno=0'
NETTYPE
=answerctc
— Channel-to-Channel communication. For point-to-point TCP/IP or TTY.
lcs
— LAN Channel Station (LCS).
qeth
— QETH (QDIO Ethernet). This is the default network interface. It is the preferred installation method for supporting real or virtual OSA cards and HiperSockets devices.
ip
command of the iproute package now supports assigning multiple address to the same interface it is no longer necessary to use this method of binding multiple addresses to the same interface.
Note
IP
aliases in ifcfg
files. For example, if ifcfg-eth0
and ifcfg-eth0:1
files are present, NetworkManager creates two connections, which will cause confusion.
IPv4
or IPv6
tab in NetworkManager to assign multiple IP
address to the same interface. For more information on using this tool, see the Fedora Networking Guide.
ifcfg-if-name:alias-value
naming scheme. Do not confuse alias ifcfg
file and interface names with VLAN ifcfg
file and interface names which take the form: ifcfg-if-name.vlan-id
and ethX.
vlan-id respectively.
ifcfg-eth0:0
file could be configured to specify DEVICE=eth0:0
and a static IP
address of 10.0.0.2
, serving as an alias of an Ethernet interface already configured to receive its IP
information via DHCP
in ifcfg-eth0
. Under this configuration, eth0
is bound to a dynamic IP
address, but the same physical network card can receive requests via the fixed, 10.0.0.2
IP
address.
Warning
DHCP
.
ifcfg-if-name-clone-name
. While an alias file allows multiple addresses for an existing interface, a clone file is used to specify additional options for an interface. For example, a standard DHCP
Ethernet interface called eth0
, may look similar to this:
DEVICE=eth0 ONBOOT=yes BOOTPROTO=dhcp
USERCTL
directive is no
if it is not specified, users cannot bring this interface up and down. To give users the ability to control the interface, create a clone by copying ifcfg-eth0
to ifcfg-eth0-user
and add the following line to ifcfg-eth0-user
:
USERCTL=yes
eth0
interface using the /sbin/ifup eth0-user
command because the configuration options from ifcfg-eth0
and ifcfg-eth0-user
are combined. While this is a very basic example, this method can be used with a variety of options and interfaces.
IP
address to the same interface. For new installations, users should select the Manual method on the IPv4
or IPv6
tab in NetworkManager to assign multiple IP
address to the same interface. For more information on using this tool, see the Fedora Networking Guide.
PPP
interface files are named using the following format:
ifcfg-pppX
PPP
interface configuration file is created automatically when wvdial
, or Kppp is used to create a dialup account. It is also possible to create and edit this file manually.
/etc/sysconfig/network-scripts/ifcfg-ppp0
file:
DEVICE=ppp0 NAME=test WVDIALSECT=test MODEMPORT=/dev/modem LINESPEED=115200 PAPNAME=test USERCTL=true ONBOOT=no PERSIST=no DEFROUTE=yes PEERDNS=yes DEMAND=no IDLETIMEOUT=600
SLIP
files have interface configuration file names such as ifcfg-sl0
.
DEFROUTE
=answer yes
— Set this interface as the default route.
no
— Do not set this interface as the default route.
DEMAND
=answeryes
— This interface allows pppd
to initiate a connection when someone attempts to use it.
no
— A connection must be manually established for this interface.
IDLETIMEOUT
=valueINITSTRING
=stringSLIP
interfaces.
LINESPEED
=value57600
, 38400
, 19200
, and 9600
.
MODEMPORT
=deviceMTU
=value576
results in fewer packets dropped and a slight improvement to the throughput for a connection.
NAME
=namePAPNAME
=namePERSIST
=answeryes
— This interface should be kept active at all times, even if deactivated after a modem hang up.
no
— This interface should not be kept active at all times.
REMIP
=addressIP
address of the remote system. This is usually left unspecified.
WVDIALSECT
=name /etc/wvdial.conf
. This file contains the phone number to be dialed and other important information for the interface.
ifcfg-lo
IP
address pointing back to the same system. Any data sent to the loopback device is immediately returned to the host's network layer.
Do not manually edit the ifcfg-lo script
/etc/sysconfig/network-scripts/ifcfg-lo
, should never be edited manually. Doing so can prevent the system from operating correctly.
ifcfg-irlan0
ifcfg-plip0
ifcfg-hsiN
/etc/sysconfig/network-scripts/
directory: /sbin/ifdown
and /sbin/ifup
.
ifup
and ifdown
interface scripts are symbolic links to scripts in the /sbin/
directory. When either of these scripts are called, they require the value of the interface to be specified, such as:
ifup eth0
Use the ifup and ifdown interface scripts
ifup
and ifdown
interface scripts are the only scripts that the user should use to bring up and take down network interfaces.
/etc/rc.d/init.d/functions
and /etc/sysconfig/network-scripts/network-functions
. Refer to Section 1.4, “Network Function Files” for more information.
/etc/sysconfig/network-scripts/
directory:
ifup-aliases
IP
aliases from interface configuration files when more than one IP
address is associated with an interface.
ifup-ippp
and ifdown-ippp
ifup-ipv6
and ifdown-ipv6
IPv6
interfaces up and down.
ifup-plip
PLIP
interface.
ifup-plusb
ifup-post
and ifdown-post
ifup-ppp
and ifdown-ppp
PPP
interface up or down.
ifup-routes
ifdown-sit
and ifup-sit
IPv6
tunnel within an IPv4
connection.
ifup-wireless
Be careful when removing or modifying network scripts!
/etc/sysconfig/network-scripts/
directory can cause interface connections to act irregularly or fail. Only advanced users should modify scripts related to a network interface.
/sbin/service
command on the network service (/etc/rc.d/init.d/network
), as illustrated by the following command:
/sbin/service network action
start
, stop
, or restart
.
/sbin/service network status
/etc/sysconfig/network-scripts/network-functions
file contains the most commonly used IPv4
functions, which are useful to many interface control scripts. These functions include contacting running programs that have requested information about changes in the status of an interface, setting host names, finding a gateway device, verifying whether or not a particular device is down, and adding a default route.
IPv6
interfaces are different from IPv4
interfaces, a /etc/sysconfig/network-scripts/network-functions-ipv6
file exists specifically to hold this information. The functions in this file configure and delete static IPv6
routes, create and remove tunnels, add and remove IPv6
addresses to an interface, and test for the existence of an IPv6
address on an interface.
ethtool -h
or refer to the man page, ethtool(8)
, for a more comprehensive list and explanation. The first two examples are information queries and show the use of the different formats of the command.
ethtool
[option...] devname
root
. Here is an example of the output when the command is run as root
:
~]# ethtool em1
Settings for em1:
Supported ports: [ TP ]
Supported link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
1000baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Speed: 1000Mb/s
Duplex: Full
Port: Twisted Pair
PHYAD: 2
Transceiver: internal
Auto-negotiation: on
MDI-X: on
Supports Wake-on: pumbg
Wake-on: g
Current message level: 0x00000007 (7)
drv probe link
Link detected: yes
ethtool
-i, --driver
devname
~]$ ethtool -i em1
driver: e1000e
version: 2.0.0-k
firmware-version: 0.13-3
bus-info: 0000:00:19.0
supports-statistics: yes
supports-test: yes
supports-eeprom-access: yes
supports-register-dump: yes
-short
and --long
form:
--statistics
--statistics
or -S
queries the specified network device for NIC and driver statistics. It takes the following form:
-S
,--statistics
devname
--identify
--identify
or -p
option initiates adapter-specific action intended to enable an operator to easily identify the adapter by sight. Typically this involves blinking one or more LEDs on the specified network port. It takes the following form:
-p, --identify
devname integer
--show-time-stamping
--show-time-stamping
or -T
option queries the specified network device for time stamping parameters. It takes the following form:
-T, --show-time-stamping
devname
--show-offload
--show-features
, or --show-offload
, or -k
option queries the specified network device for the state of protocol offload and other features. It takes the following form:
-k, --show-features, --show-offload
devname
--test
--test
or -t
option is used to perform tests on a Network Interface Card. It takes the following form:
-t, --test
devname word
offline
— Perform a comprehensive set of tests. Service will be interrupted.
online
— Perform a reduced set of tests. Service should not be interrupted.
external_lb
— Perform full set of tests including loopback tests while fitted with a loopback cable.
-s
or --change
option. All the following options are only applied if the -s
or --change
option is also specified. For the sake of clarity we will omit it here.
ETHTOOL_OPTS
directive. It can be used in interface configuration files to set the desired options when the network interface is brought up. Refer to Section 1.2.1, “Ethernet Interfaces” for more details on how to use this directive.
--offload
--features
, or --offload
, or -K
option changes the offload parameters and other features of the specified network device. It takes the following form:
-K, --features, --offload
devname feature boolean
ON
or OFF
,
ethtool(8)
man page lists most features. As the feature set is dependent on the NIC driver, you should consult the driver documentation for features not listed in the man page.
--speed
--speed
option is used to set the speed in megabits per second (Mb/s). Omitting the speed value will show the supported device speeds. It takes the following form:
--speed
number devname
--duplex
--duplex
option is used to set the transmit and receive mode of operation. It takes the following form:
--duplex
word devname
half
— Sets half-duplex mode. Usually used when connected to a hub.
full
— Sets full-duplex mode. Usually used when connected to a switch or another host.
--port
--port
option is used to select the device port . It takes the following form:
--port
value devname
tp
— An Ethernet interface using Twisted-Pair cable as the medium.
aui
— Attachment Unit Interface (AUI). Normally used with hubs.
bnc
— An Ethernet interface using BNC connectors and co-axial cable.
mii
— An Ethernet interface using a Media Independent Interface (MII).
fibre
— An Ethernet interface using Optical Fibre as the medium.
--autoneg
--autoneg
option is used to control auto-negotiation of network speed and mode of operation (full-duplex or half-duplex mode). If auto-negotiation is enabled you can initiate re-negotiation of network speeds and mode of operation by using the -r, --negotiate
option. You can display the auto-negotiation state using the --a, --show-pause
option.
--autoneg
value devname
yes
— Allow auto-negotiating of network speed and mode of operation.
no
— Do not allow auto-negotiating of network speed and mode of operation.
--advertise
--advertise
option is used to set what speeds and modes of operation (duplex mode) are advertised for auto-negotiation. The argument is one or more hexadecimal values from Table 1.1, “Ethtool advertise options: speed and mode of operation”.
--advertise
option devname
Table 1.1. Ethtool advertise options: speed and mode of operation
Hex Value | Speed | Duplex Mode | IEEE standard? |
---|---|---|---|
0x001 | 10 | Half | Yes |
0x002 | 10 | Full | Yes |
0x004 | 100 | Half | Yes |
0x008 | 100 | Full | Yes |
0x010 | 1000 | Half | No |
0x020 | 1000 | Full | Yes |
0x8000 | 2500 | Full | Yes |
0x1000 | 10000 | Full | Yes |
0x20000 | 20000MLD2 | Full | No |
0x20000 | 20000MLD2 | Full | No |
0x40000 | 20000KR2 | Full | No |
--phyad
--phyad
option is used to change the physical address. Often referred to as the MAC or hardware address but in this context referred to as the physical address.
--phyad
physical_address devname
--xcvr
--xcvr
option is used to select the transceiver type. Currently only “internal” and “external” can be specified. In the future other types might be added.
--xcvr
word devname
internal
— Use internal transceiver.
external
— Use external transceiver.
--wol
--wol
option is used to set “Wake-on-LAN” options. Not all devices support this. The argument to this option is a string of characters specifying which options to enable.
--wol
value devname
p
— Wake on PHY activity.
u
— Wake on unicast messages.
m
— Wake on multicast messages.
b
— Wake on broadcast messages.
g
— Wake-on-Lan; wake on receipt of a "magic packet".
s
— Enable security function using password for Wake-on-Lan.
d
— Disable Wake-on-Lan and clear all settings.
--sopass
--sopass
option is used to set the “SecureOn” password. The argument to this option must be 6 bytes in Ethernet MAC hexadecimal format (xx:yy:zz:aa:bb:cc).
--sopass
xx:yy:zz:aa:bb:cc devname
--msglvl
--msglvl
option is used to set the driver message-type flags by name or number. The precise meanings of these type flags differ between drivers.
--msglvl
message_type devname
Table 1.2. Driver message type
Message Type | Hex Value | Description |
---|---|---|
drv | 0x0001 |
General driver status
|
probe | 0x0002 |
Hardware probing
|
link | 0x0004 |
Link state
|
timer | 0x0008 |
Periodic status check
|
ifdown | 0x0010 | Interface being brought down |
ifup | 0x0020 |
Interface being brought up
|
rx_err | 0x0040 | Receive error |
tx_err | 0x0080 | Transmit error |
intr | 0x0200 | Interrupt handling |
tx_done | 0x0400 | Transmit completion |
rx_status | 0x0800 | Receive completion |
pktdata | 0x1000 | Packet contents |
hw | 0x2000 | Hardware status |
wol | 0x4000 | Wake-on-LAN status |
/usr/share/doc/initscripts/sysconfig.txt
IPv6
options not covered in this chapter.
ip
command, which can be used to manipulate routing tables, among other things. The information can also be found in the ip-cref.ps
file by installing the iproute-doc sub-package from the optional content channel.
/proc
directory (also called the proc
file system) contains a hierarchy of special files which represent the current state of the kernel, allowing applications and users to peer into the kernel's view of the system.
/proc
directory contains a wealth of information detailing system hardware and any running processes. In addition, some of the files within /proc
can be manipulated by users and applications to communicate configuration changes to the kernel.
Note
/proc/ide/
and /proc/pci/
directories obsolete. The /proc/ide/
file system is now superseded by files in sysfs
; to retrieve information on PCI devices, use lspci
instead. For more information on sysfs
or lspci
, refer to their respective man
pages.
/proc
directory contains another type of file called a virtual file. As such, /proc
is often referred to as a virtual file system.
/proc/interrupts
, /proc/meminfo
, /proc/mounts
, and /proc/partitions
provide an up-to-the-moment glimpse of the system's hardware. Others, like the /proc/filesystems
file and the /proc/sys/
directory provide system configuration information and interfaces.
/proc
files operate similarly to text files, storing useful system and hardware data in human-readable text format. As such, you can use cat
, more
, or less
to view them. For example, to display information about the system's CPU, run cat /proc/cpuinfo
. This will return output similar to the following:
processor : 0 vendor_id : AuthenticAMD cpu family : 5 model : 9 model name : AMD-K6(tm) 3D+ Processor stepping : 1 cpu MHz : 400.919 cache size : 256 KB fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 1 wp : yes flags : fpu vme de pse tsc msr mce cx8 pge mmx syscall 3dnow k6_mtrr bogomips : 799.53
/proc
contain information that is not human-readable. To retrieve information from such files, use tools such as lspci
, apm
, free
, and top
.
Note
/proc
directory are readable only by the root user.
/proc
directory are read-only. However, some can be used to adjust settings in the kernel. This is especially true for files in the /proc/sys/
subdirectory.
echo value > /proc/file_name
echo www.example.com > /proc/sys/kernel/hostname
cat /proc/sys/net/ipv4/ip_forward
returns either a 0
(off or false) or a 1
(on or true). A 0
indicates that the kernel is not forwarding network packets. To turn packet forwarding on, run:
echo 1 > /proc/sys/net/ipv4/ip_forward
Note
/proc/sys/
subdirectory is /sbin/sysctl
. For more information on this command, refer to Section 2.4, “Using the sysctl Command”
/proc/sys/
subdirectory, refer to Section 2.3.9, “/proc/sys/”.
/proc
directory.
Note
DMA
row references the first 16 MB on a system, the HighMem
row references all memory greater than 4 GB on a system, and the Normal
row references all memory in between.
/proc/buddyinfo
:
Node 0, zone DMA 90 6 2 1 1 ... Node 0, zone Normal 1650 310 5 0 0 ... Node 0, zone HighMem 2 0 0 1 1 ...
/proc/cmdline
file looks like the following:
ro root=/dev/VolGroup00/LogVol00 rhgb quiet 3
(ro)
), located on the first logical volume (LogVol00
) of the first volume group (/dev/VolGroup00
). LogVol00
is the equivalent of a disk partition in a non-LVM system (Logical Volume Management), just as /dev/VolGroup00
is similar in concept to /dev/hda1
, but much more extensible.
rhgb
signals that the rhgb
package has been installed, and graphical booting is supported, assuming /etc/inittab
shows a default runlevel set to id:5:initdefault:
.
quiet
indicates all verbose kernel messages are suppressed at boot time.
/proc/cpuinfo
:
processor : 0 vendor_id : GenuineIntel cpu family : 15 model : 2 model name : Intel(R) Xeon(TM) CPU 2.40GHz stepping : 7 cpu MHz : 2392.371 cache size : 512 KB physical id : 0 siblings : 2 runqueue : 0 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 2 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm bogomips : 4771.02
processor
— Provides each processor with an identifying number. On systems that have one processor, only a 0
is present.
cpu family
— Authoritatively identifies the type of processor in the system. For an Intel-based system, place the number in front of "86" to determine the value. This is particularly helpful for those attempting to identify the architecture of an older system such as a 586, 486, or 386. Because some RPM packages are compiled for each of these particular architectures, this value also helps users determine which packages to install.
model name
— Displays the common name of the processor, including its project name.
cpu MHz
— Shows the precise speed in megahertz for the processor to the thousandths decimal place.
cache size
— Displays the amount of level 2 memory cache available to the processor.
siblings
— Displays the number of sibling CPUs on the same physical CPU for architectures which use hyper-threading.
flags
— Defines a number of different qualities about the processor, such as the presence of a floating point unit (FPU) and the ability to process MMX instructions.
/proc/crypto
file looks like the following:
name : sha1 module : kernel type : digest blocksize : 64 digestsize : 20 name : md5 module : md5 type : digest blocksize : 64 digestsize : 16
Character devices: 1 mem 4 /dev/vc/0 4 tty 4 ttyS 5 /dev/tty 5 /dev/console 5 /dev/ptmx 7 vcs 10 misc 13 input 29 fb 36 netlink 128 ptm 136 pts 180 usb Block devices: 1 ramdisk 3 ide0 9 md 22 ide1 253 device-mapper 254 mdp
/proc/devices
includes the major number and name of the device, and is broken into two major sections: Character devices
and Block devices
.
/usr/share/doc/kernel-doc-kernel_version/Documentation/devices.txt
file.
/proc/dma
files looks like the following:
4: cascade
0-0 Linux [kernel]
PER_LINUX
execution domain, different personalities can be implemented as dynamically loadable modules.
/proc/fb
for systems which contain frame buffer devices looks similar to the following:
0 VESA VGA
/proc/filesystems
file looks similar to the following:
nodev sysfs nodev rootfs nodev bdev nodev proc nodev sockfs nodev binfmt_misc nodev usbfs nodev usbdevfs nodev futexfs nodev tmpfs nodev pipefs nodev eventpollfs nodev devpts ext2 nodev ramfs nodev hugetlbfs iso9660 nodev mqueue ext3 nodev rpc_pipefs nodev autofs
nodev
are not mounted on a device. The second column lists the names of the file systems supported.
mount
command cycles through the file systems listed here when one is not specified as an argument.
/proc/interrupts
looks similar to the following:
CPU0 0: 80448940 XT-PIC timer 1: 174412 XT-PIC keyboard 2: 0 XT-PIC cascade 8: 1 XT-PIC rtc 10: 410964 XT-PIC eth0 12: 60330 XT-PIC PS/2 Mouse 14: 1314121 XT-PIC ide0 15: 5195422 XT-PIC ide1 NMI: 0 ERR: 0
CPU0 CPU1 0: 1366814704 0 XT-PIC timer 1: 128 340 IO-APIC-edge keyboard 2: 0 0 XT-PIC cascade 8: 0 1 IO-APIC-edge rtc 12: 5323 5793 IO-APIC-edge PS/2 Mouse 13: 1 0 XT-PIC fpu 16: 11184294 15940594 IO-APIC-level Intel EtherExpress Pro 10/100 Ethernet 20: 8450043 11120093 IO-APIC-level megaraid 30: 10432 10722 IO-APIC-level aic7xxx 31: 23 22 IO-APIC-level aic7xxx NMI: 0 ERR: 0
XT-PIC
— This is the old AT computer interrupts.
IO-APIC-edge
— The voltage signal on this interrupt transitions from low to high, creating an edge, where the interrupt occurs and is only signaled once. This kind of interrupt, as well as the IO-APIC-level
interrupt, are only seen on systems with processors from the 586 family and higher.
IO-APIC-level
— Generates interrupts when its voltage signal is high until the signal is low again.
00000000-0009fbff : System RAM 0009fc00-0009ffff : reserved 000a0000-000bffff : Video RAM area 000c0000-000c7fff : Video ROM 000f0000-000fffff : System ROM 00100000-07ffffff : System RAM 00100000-00291ba8 : Kernel code 00291ba9-002e09cb : 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 [FasterNet] ea000000-ea00007f : tulip ffff0000-ffffffff : reserved
/proc/ioports
provides a list of currently registered port regions used for input or output communication with a device. This file can be quite long. The following is a partial listing:
0000-001f : dma1 0020-003f : pic1 0040-005f : timer 0060-006f : keyboard 0070-007f : rtc 0080-008f : dma page reg 00a0-00bf : pic2 00c0-00df : dma2 00f0-00ff : fpu 0170-0177 : ide1 01f0-01f7 : ide0 02f8-02ff : serial(auto) 0376-0376 : ide1 03c0-03df : vga+ 03f6-03f6 : ide0 03f8-03ff : serial(auto) 0cf8-0cff : PCI conf1 d000-dfff : PCI Bus #01 e000-e00f : VIA Technologies, Inc. Bus Master IDE e000-e007 : ide0 e008-e00f : ide1 e800-e87f : Digital Equipment Corporation DECchip 21140 [FasterNet] e800-e87f : tulip
/proc
files, kcore
displays a size. This value is given in bytes and is equal to the size of the physical memory (RAM) used plus 4 KB.
gdb
, and is not human readable.
Warning
/proc/kcore
virtual file. The contents of the file scramble text output on the terminal. If this file is accidentally viewed, press Ctrl+C to stop the process and then type reset
to bring back the command line prompt.
/sbin/klogd
or /bin/dmesg
.
uptime
and other commands. A sample /proc/loadavg
file looks similar to the following:
0.20 0.18 0.12 1/80 11206
/proc/locks
file for a lightly loaded system looks similar to the following:
1: POSIX ADVISORY WRITE 3568 fd:00:2531452 0 EOF 2: FLOCK ADVISORY WRITE 3517 fd:00:2531448 0 EOF 3: POSIX ADVISORY WRITE 3452 fd:00:2531442 0 EOF 4: POSIX ADVISORY WRITE 3443 fd:00:2531440 0 EOF 5: POSIX ADVISORY WRITE 3326 fd:00:2531430 0 EOF 6: POSIX ADVISORY WRITE 3175 fd:00:2531425 0 EOF 7: POSIX ADVISORY WRITE 3056 fd:00:2548663 0 EOF
FLOCK
signifying the older-style UNIX file locks from a flock
system call and POSIX
representing the newer POSIX locks from the lockf
system call.
ADVISORY
or MANDATORY
. ADVISORY
means that the lock does not prevent other people from accessing the data; it only prevents other attempts to lock it. MANDATORY
means that no other access to the data is permitted while the lock is held. The fourth column reveals whether the lock is allowing the holder READ
or WRITE
access to the file. The fifth column shows the ID of the process holding the lock. The sixth column shows the ID of the file being locked, in the format of MAJOR-DEVICE:MINOR-DEVICE:INODE-NUMBER
. The seventh and eighth column shows the start and end of the file's locked region.
/proc/mdstat
looks similar to the following:
Personalities : read_ahead not set unused devices: <none>
md
device is present. In that case, view /proc/mdstat
to find the current status of mdX
RAID devices.
/proc/mdstat
file below shows a system with its md0
configured as a RAID 1 device, while it is currently re-syncing the disks:
Personalities : [linear] [raid1] read_ahead 1024 sectors md0: active raid1 sda2[1] sdb2[0] 9940 blocks [2/2] [UU] resync=1% finish=12.3min algorithm 2 [3/3] [UUU] unused devices: <none>
/proc
directory, as it reports a large amount of valuable information about the systems RAM usage.
/proc/meminfo
virtual file is from a system with 256 MB of RAM and 512 MB of swap space:
MemTotal: 255908 kB MemFree: 69936 kB Buffers: 15812 kB Cached: 115124 kB SwapCached: 0 kB Active: 92700 kB Inactive: 63792 kB HighTotal: 0 kB HighFree: 0 kB LowTotal: 255908 kB LowFree: 69936 kB SwapTotal: 524280 kB SwapFree: 524280 kB Dirty: 4 kB Writeback: 0 kB Mapped: 42236 kB Slab: 25912 kB Committed_AS: 118680 kB PageTables: 1236 kB VmallocTotal: 3874808 kB VmallocUsed: 1416 kB VmallocChunk: 3872908 kB HugePages_Total: 0 HugePages_Free: 0 Hugepagesize: 4096 kB
free
, top
, and ps
commands. In fact, the output of the free
command is similar in appearance to the contents and structure of /proc/meminfo
. But by looking directly at /proc/meminfo
, more details are revealed:
MemTotal
— Total amount of physical RAM, in kilobytes.
MemFree
— The amount of physical RAM, in kilobytes, left unused by the system.
Buffers
— The amount of physical RAM, in kilobytes, used for file buffers.
Cached
— The amount of physical RAM, in kilobytes, used as cache memory.
SwapCached
— The amount of swap, in kilobytes, used as cache memory.
Active
— The total amount of buffer or page cache memory, in kilobytes, that is in active use. This is memory that has been recently used and is usually not reclaimed for other purposes.
Inactive
— The total amount of buffer or page cache memory, in kilobytes, that are free and available. This is memory that has not been recently used and can be reclaimed for other purposes.
HighTotal
and HighFree
— The total and free amount of memory, in kilobytes, that is not directly mapped into kernel space. The HighTotal
value can vary based on the type of kernel used.
LowTotal
and LowFree
— The total and free amount of memory, in kilobytes, that is directly mapped into kernel space. The LowTotal
value can vary based on the type of kernel used.
SwapTotal
— The total amount of swap available, in kilobytes.
SwapFree
— The total amount of swap free, in kilobytes.
Dirty
— The total amount of memory, in kilobytes, waiting to be written back to the disk.
Writeback
— The total amount of memory, in kilobytes, actively being written back to the disk.
Mapped
— The total amount of memory, in kilobytes, which have been used to map devices, files, or libraries using the mmap
command.
Slab
— The total amount of memory, in kilobytes, used by the kernel to cache data structures for its own use.
Committed_AS
— The total amount of memory, in kilobytes, estimated to complete the workload. This value represents the worst case scenario value, and also includes swap memory.
PageTables
— The total amount of memory, in kilobytes, dedicated to the lowest page table level.
VMallocTotal
— The total amount of memory, in kilobytes, of total allocated virtual address space.
VMallocUsed
— The total amount of memory, in kilobytes, of used virtual address space.
VMallocChunk
— The largest contiguous block of memory, in kilobytes, of available virtual address space.
HugePages_Total
— The total number of hugepages for the system. The number is derived by dividing Hugepagesize
by the megabytes set aside for hugepages specified in /proc/sys/vm/hugetlb_pool
. This statistic only appears on the x86, Itanium, and AMD64 architectures.
HugePages_Free
— The total number of hugepages available for the system. This statistic only appears on the x86, Itanium, and AMD64 architectures.
Hugepagesize
— The size for each hugepages unit in kilobytes. By default, the value is 4096 KB on uniprocessor kernels for 32 bit architectures. For SMP, hugemem kernels, and AMD64, the default is 2048 KB. For Itanium architectures, the default is 262144 KB. This statistic only appears on the x86, Itanium, and AMD64 architectures.
63 device-mapper 175 agpgart 135 rtc 134 apm_bios
/proc/modules
file output:
Note
/sbin/lsmod
command.
nfs 170109 0 - Live 0x129b0000 lockd 51593 1 nfs, Live 0x128b0000 nls_utf8 1729 0 - Live 0x12830000 vfat 12097 0 - Live 0x12823000 fat 38881 1 vfat, Live 0x1287b000 autofs4 20293 2 - Live 0x1284f000 sunrpc 140453 3 nfs,lockd, Live 0x12954000 3c59x 33257 0 - Live 0x12871000 uhci_hcd 28377 0 - Live 0x12869000 md5 3777 1 - Live 0x1282c000 ipv6 211845 16 - Live 0x128de000 ext3 92585 2 - Live 0x12886000 jbd 65625 1 ext3, Live 0x12857000 dm_mod 46677 3 - Live 0x12833000
Live
, Loading
, or Unloading
are the only possible values.
oprofile
.
rootfs / rootfs rw 0 0 /proc /proc proc rw,nodiratime 0 0 none /dev ramfs rw 0 0 /dev/mapper/VolGroup00-LogVol00 / ext3 rw 0 0 none /dev ramfs rw 0 0 /proc /proc proc rw,nodiratime 0 0 /sys /sys sysfs rw 0 0 none /dev/pts devpts rw 0 0 usbdevfs /proc/bus/usb usbdevfs rw 0 0 /dev/hda1 /boot ext3 rw 0 0 none /dev/shm tmpfs rw 0 0 none /proc/sys/fs/binfmt_misc binfmt_misc rw 0 0 sunrpc /var/lib/nfs/rpc_pipefs rpc_pipefs rw 0 0
/etc/mtab
, except that /proc/mounts
is more up-to-date.
ro
) or read-write (rw
). The fifth and sixth columns are dummy values designed to match the format used in /etc/mtab
.
/proc/mtrr
file may look similar to the following:
reg00: base=0x00000000 ( 0MB), size= 256MB: write-back, count=1 reg01: base=0xe8000000 (3712MB), size= 32MB: write-combining, count=1
/proc/mtrr
file can increase performance more than 150%.
/usr/share/doc/kernel-doc-<kernel_version>/Documentation/<arch>/mtrr.txt
file.
major minor #blocks name 3 0 19531250 hda 3 1 104391 hda1 3 2 19422585 hda2 253 0 22708224 dm-0 253 1 524288 dm-1
major
— The major number of the device with this partition. The major number in the /proc/partitions
, (3
), corresponds with the block device ide0
, in /proc/devices
.
minor
— The minor number of the device with this partition. This serves to separate the partitions into different physical devices and relates to the number at the end of the name of the partition.
#blocks
— Lists the number of physical disk blocks contained in a particular partition.
name
— The name of the partition.
/proc/slabinfo
file manually, the /usr/bin/slabtop
program displays kernel slab cache information in real time. This program allows for custom configurations, including column sorting and screen refreshing.
/usr/bin/slabtop
usually looks like the following example:
Active / Total Objects (% used) : 133629 / 147300 (90.7%) Active / Total Slabs (% used) : 11492 / 11493 (100.0%) Active / Total Caches (% used) : 77 / 121 (63.6%) Active / Total Size (% used) : 41739.83K / 44081.89K (94.7%) Minimum / Average / Maximum Object : 0.01K / 0.30K / 128.00K OBJS ACTIVE USE OBJ SIZE SLABS OBJ/SLAB CACHE SIZE NAME 44814 43159 96% 0.62K 7469 6 29876K ext3_inode_cache 36900 34614 93% 0.05K 492 75 1968K buffer_head 35213 33124 94% 0.16K 1531 23 6124K dentry_cache 7364 6463 87% 0.27K 526 14 2104K radix_tree_node 2585 1781 68% 0.08K 55 47 220K vm_area_struct 2263 2116 93% 0.12K 73 31 292K size-128 1904 1125 59% 0.03K 16 119 64K size-32 1666 768 46% 0.03K 14 119 56K anon_vma 1512 1482 98% 0.44K 168 9 672K inode_cache 1464 1040 71% 0.06K 24 61 96K size-64 1320 820 62% 0.19K 66 20 264K filp 678 587 86% 0.02K 3 226 12K dm_io 678 587 86% 0.02K 3 226 12K dm_tio 576 574 99% 0.47K 72 8 288K proc_inode_cache 528 514 97% 0.50K 66 8 264K size-512 492 372 75% 0.09K 12 41 48K bio 465 314 67% 0.25K 31 15 124K size-256 452 331 73% 0.02K 2 226 8K biovec-1 420 420 100% 0.19K 21 20 84K skbuff_head_cache 305 256 83% 0.06K 5 61 20K biovec-4 290 4 1% 0.01K 1 290 4K revoke_table 264 264 100% 4.00K 264 1 1056K size-4096 260 256 98% 0.19K 13 20 52K biovec-16 260 256 98% 0.75K 52 5 208K biovec-64
/proc/slabinfo
that are included into /usr/bin/slabtop
include:
OBJS
— The total number of objects (memory blocks), including those in use (allocated), and some spares not in use.
ACTIVE
— The number of objects (memory blocks) that are in use (allocated).
USE
— Percentage of total objects that are active. ((ACTIVE/OBJS)(100))
OBJ SIZE
— The size of the objects.
SLABS
— The total number of slabs.
OBJ/SLAB
— The number of objects that fit into a slab.
CACHE SIZE
— The cache size of the slab.
NAME
— The name of the slab.
/usr/bin/slabtop
program, refer to the slabtop
man page.
/proc/stat
, which can be quite long, usually begins like the following example:
cpu 259246 7001 60190 34250993 137517 772 0 cpu0 259246 7001 60190 34250993 137517 772 0 intr 354133732 347209999 2272 0 4 4 0 0 3 1 1249247 0 0 80143 0 422626 5169433 ctxt 12547729 btime 1093631447 processes 130523 procs_running 1 procs_blocked 0 preempt 5651840 cpu 209841 1554 21720 118519346 72939 154 27168 cpu0 42536 798 4841 14790880 14778 124 3117 cpu1 24184 569 3875 14794524 30209 29 3130 cpu2 28616 11 2182 14818198 4020 1 3493 cpu3 35350 6 2942 14811519 3045 0 3659 cpu4 18209 135 2263 14820076 12465 0 3373 cpu5 20795 35 1866 14825701 4508 0 3615 cpu6 21607 0 2201 14827053 2325 0 3334 cpu7 18544 0 1550 14831395 1589 0 3447 intr 15239682 14857833 6 0 6 6 0 5 0 1 0 0 0 29 0 2 0 0 0 0 0 0 0 94982 0 286812 ctxt 4209609 btime 1078711415 processes 21905 procs_running 1 procs_blocked 0
cpu
— Measures the number of jiffies (1/100 of a second for x86 systems) that the system has been in user mode, user mode with low priority (nice), system mode, idle task, I/O wait, IRQ (hardirq), and softirq respectively. The IRQ (hardirq) is the direct response to a hardware event. The IRQ takes minimal work for queuing the "heavy" work up for the softirq to execute. The softirq runs at a lower priority than the IRQ and therefore may be interrupted more frequently. The total for all CPUs is given at the top, while each individual CPU is listed below with its own statistics. The following example is a 4-way Intel Pentium Xeon configuration with multi-threading enabled, therefore showing four physical processors and four virtual processors totaling eight processors.
page
— The number of memory pages the system has written in and out to disk.
swap
— The number of swap pages the system has brought in and out.
intr
— The number of interrupts the system has experienced.
btime
— The boot time, measured in the number of seconds since January 1, 1970, otherwise known as the epoch.
/proc/swaps
may look similar to the following:
Filename Type Size Used Priority /dev/mapper/VolGroup00-LogVol01 partition 524280 0 -1
/proc
directory, /proc/swap
provides a snapshot of every swap file name, the type of swap space, the total size, and the amount of space 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.
echo
command to write to this file, a remote root user can execute most System Request Key commands remotely as if at the local terminal. To echo
values to this file, the /proc/sys/kernel/sysrq
must be set to a value other than 0
. For more information about the System Request Key, refer to Section 2.3.9.3, “/proc/sys/kernel/”.
/proc/uptime
is quite minimal:
350735.47 234388.90
gcc
used to compile the kernel, and the time of kernel compilation. It also contains the kernel compiler's user name (in parentheses).
Linux version 2.6.8-1.523 (user@foo.redhat.com) (gcc version 3.4.1 20040714 \ (Red Hat Enterprise Linux 3.4.1-7)) #1 Mon Aug 16 13:27:03 EDT 2004
/proc
directory.
/proc
directory contains a number of directories with numerical names. A listing of them may be similar to the following:
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
/proc
process directory vanishes.
cmdline
— Contains the command issued when starting the process.
cwd
— A symbolic link to the current working directory for the process.
environ
— A list of the environment variables for the process. The environment variable is given in all upper-case characters, and the value is in lower-case characters.
exe
— A symbolic link to the executable of this process.
fd
— A directory containing all of the file descriptors for a particular process. These are given in numbered links:
total 0 lrwx------ 1 root root 64 May 8 11:31 0 -> /dev/null lrwx------ 1 root root 64 May 8 11:31 1 -> /dev/null lrwx------ 1 root root 64 May 8 11:31 2 -> /dev/null lrwx------ 1 root root 64 May 8 11:31 3 -> /dev/ptmx lrwx------ 1 root root 64 May 8 11:31 4 -> socket:[7774817] lrwx------ 1 root root 64 May 8 11:31 5 -> /dev/ptmx lrwx------ 1 root root 64 May 8 11:31 6 -> socket:[7774829] lrwx------ 1 root root 64 May 8 11:31 7 -> /dev/ptmx
maps
— A list of memory maps to the various executables and library files associated with this process. This file can be rather long, depending upon the complexity of the process, but sample output from the sshd
process begins like the following:
08048000-08086000 r-xp 00000000 03:03 391479 /usr/sbin/sshd 08086000-08088000 rw-p 0003e000 03:03 391479 /usr/sbin/sshd 08088000-08095000 rwxp 00000000 00:00 0 40000000-40013000 r-xp 0000000 03:03 293205 /lib/ld-2.2.5.so 40013000-40014000 rw-p 00013000 03:03 293205 /lib/ld-2.2.5.so 40031000-40038000 r-xp 00000000 03:03 293282 /lib/libpam.so.0.75 40038000-40039000 rw-p 00006000 03:03 293282 /lib/libpam.so.0.75 40039000-4003a000 rw-p 00000000 00:00 0 4003a000-4003c000 r-xp 00000000 03:03 293218 /lib/libdl-2.2.5.so 4003c000-4003d000 rw-p 00001000 03:03 293218 /lib/libdl-2.2.5.so
mem
— The memory held by the process. This file cannot be read by the user.
root
— A link to the root directory of the process.
stat
— The status of the process.
statm
— The status of the memory in use by the process. Below is a sample /proc/statm
file:
263 210 210 5 0 205 0
status
— The status of the process in a more readable form than stat
or statm
. Sample output for sshd
looks similar to the following:
Name: sshd State: S (sleeping) Tgid: 797 Pid: 797 PPid: 1 TracerPid: 0 Uid: 0 0 0 0 Gid: 0 0 0 0 FDSize: 32 Groups: VmSize: 3072 kB VmLck: 0 kB VmRSS: 840 kB VmData: 104 kB VmStk: 12 kB VmExe: 300 kB VmLib: 2528 kB SigPnd: 0000000000000000 SigBlk: 0000000000000000 SigIgn: 8000000000001000 SigCgt: 0000000000014005 CapInh: 0000000000000000 CapPrm: 00000000fffffeff CapEff: 00000000fffffeff
S (sleeping)
or R (running)
), user/group ID running the process, and detailed data regarding memory usage.
/proc/self/
directory is a link to the currently running process. This allows a process to look at itself without having to know its process ID.
/proc/self/
directory produces the same contents as listing the process directory for that process.
/proc/bus/
by the same name, such as /proc/bus/pci/
.
/proc/bus/
vary depending on the devices connected to the system. However, each bus type has at least one directory. Within these bus directories are normally at least one subdirectory with a numerical name, such as 001
, which contain binary files.
/proc/bus/usb/
subdirectory contains files that track the various devices on any USB buses, as well as the drivers required for them. The following is a sample listing of a /proc/bus/usb/
directory:
total 0 dr-xr-xr-x 1 root root 0 May 3 16:25 001 -r--r--r-- 1 root root 0 May 3 16:25 devices -r--r--r-- 1 root root 0 May 3 16:25 drivers
/proc/bus/usb/001/
directory contains all devices on the first USB bus and the devices
file identifies the USB root hub on the motherboard.
/proc/bus/usb/devices
file:
T: Bus=01 Lev=00 Prnt=00 Port=00 Cnt=00 Dev#= 1 Spd=12 MxCh= 2 B: Alloc= 0/900 us ( 0%), #Int= 0, #Iso= 0 D: Ver= 1.00 Cls=09(hub ) Sub=00 Prot=00 MxPS= 8 #Cfgs= 1 P: Vendor=0000 ProdID=0000 Rev= 0.00 S: Product=USB UHCI Root Hub S: SerialNumber=d400 C:* #Ifs= 1 Cfg#= 1 Atr=40 MxPwr= 0mA I: If#= 0 Alt= 0 #EPs= 1 Cls=09(hub ) Sub=00 Prot=00 Driver=hub E: Ad=81(I) Atr=03(Int.) MxPS= 8 Ivl=255ms
/proc/pci
directory in favor of the /proc/bus/pci
directory. Although you can get a list of all PCI devices present on the system using the command cat /proc/bus/pci/devices
, the output is difficult to read and interpret.
~]# /sbin/lspci -vb
00:00.0 Host bridge: Intel Corporation 82X38/X48 Express DRAM Controller
Subsystem: Hewlett-Packard Company Device 1308
Flags: bus master, fast devsel, latency 0
Capabilities: [e0] Vendor Specific Information <?>
Kernel driver in use: x38_edac
Kernel modules: x38_edac
00:01.0 PCI bridge: Intel Corporation 82X38/X48 Express Host-Primary PCI Express Bridge (prog-if 00 [Normal decode])
Flags: bus master, fast devsel, latency 0
Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
I/O behind bridge: 00001000-00001fff
Memory behind bridge: f0000000-f2ffffff
Capabilities: [88] Subsystem: Hewlett-Packard Company Device 1308
Capabilities: [80] Power Management version 3
Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
Capabilities: [a0] Express Root Port (Slot+), MSI 00
Capabilities: [100] Virtual Channel <?>
Capabilities: [140] Root Complex Link <?>
Kernel driver in use: pcieport
Kernel modules: shpchp
00:1a.0 USB Controller: Intel Corporation 82801I (ICH9 Family) USB UHCI Controller #4 (rev 02) (prog-if 00 [UHCI])
Subsystem: Hewlett-Packard Company Device 1308
Flags: bus master, medium devsel, latency 0, IRQ 5
I/O ports at 2100
Capabilities: [50] PCI Advanced Features
Kernel driver in use: uhci_hcd
[output truncated]
rtc
which provides output from the driver for the system's Real Time Clock (RTC), the device that keeps the time while the system is switched off. Sample output from /proc/driver/rtc
looks like the following:
rtc_time : 16:21:00 rtc_date : 2004-08-31 rtc_epoch : 1900 alarm : 21:16:27 DST_enable : no BCD : yes 24hr : yes square_wave : no alarm_IRQ : no update_IRQ : no periodic_IRQ : no periodic_freq : 1024 batt_status : okay
/usr/share/doc/kernel-doc-<kernel_version>/Documentation/rtc.txt
file.
cat /proc/fs/nfsd/exports
displays the file systems being shared and the permissions granted for those file systems. For more on file system sharing with NFS, refer to the Network File System (NFS) chapter of the Storage Administration Guide.
/proc/irq/prof_cpu_mask
file is a bitmask that contains the default values for the smp_affinity
file in the IRQ directory. The values in smp_affinity
specify which CPUs handle that particular IRQ.
/proc/irq/
directory, refer to the /usr/share/doc/kernel-doc-kernel_version/Documentation/filesystems/proc.txt
.
/proc/net/
directory:
arp
— Lists the kernel's ARP table. This file is particularly useful for connecting a hardware address to an IP address on a system.
atm/
directory — The files within this directory contain Asynchronous Transfer Mode (ATM) settings and statistics. This directory is primarily used with ATM networking and ADSL cards.
dev
— Lists the various network devices configured on the system, complete with transmit and receive statistics. This file displays the number of bytes each interface has sent and received, the number of packets inbound and outbound, the number of errors seen, the number of packets dropped, and more.
dev_mcast
— Lists Layer2 multicast groups on which each device is listening.
igmp
— Lists the IP multicast addresses which this system joined.
ip_conntrack
— Lists tracked network connections for machines that are forwarding IP connections.
ip_tables_names
— Lists the types of iptables
in use. This file is only present if iptables
is active on the system and contains one or more of the following values: filter
, mangle
, or nat
.
ip_mr_cache
— Lists the multicast routing cache.
ip_mr_vif
— Lists multicast virtual interfaces.
netstat
— Contains a broad yet detailed collection of networking statistics, including TCP timeouts, SYN cookies sent and received, and much more.
psched
— Lists global packet scheduler parameters.
raw
— Lists raw device statistics.
route
— Lists the kernel's routing table.
rt_cache
— Contains the current routing cache.
snmp
— List of Simple Network Management Protocol (SNMP) data for various networking protocols in use.
sockstat
— Provides socket statistics.
tcp
— Contains detailed TCP socket information.
tr_rif
— Lists the token ring RIF routing table.
udp
— Contains detailed UDP socket information.
unix
— Lists UNIX domain sockets currently in use.
wireless
— Lists wireless interface data.
/proc/scsi/scsi
, which contains a list of every recognized SCSI device. From this listing, the type of device, as well as the model name, vendor, SCSI channel and ID data is available.
Attached devices: Host: scsi1 Channel: 00 Id: 05 Lun: 00 Vendor: NEC Model: CD-ROM DRIVE:466 Rev: 1.06 Type: CD-ROM ANSI SCSI revision: 02 Host: scsi1 Channel: 00 Id: 06 Lun: 00 Vendor: ARCHIVE Model: Python 04106-XXX Rev: 7350 Type: Sequential-Access ANSI SCSI revision: 02 Host: scsi2 Channel: 00 Id: 06 Lun: 00 Vendor: DELL Model: 1x6 U2W SCSI BP Rev: 5.35 Type: Processor ANSI SCSI revision: 02 Host: scsi2 Channel: 02 Id: 00 Lun: 00 Vendor: MegaRAID Model: LD0 RAID5 34556R Rev: 1.01 Type: Direct-Access ANSI SCSI revision: 02
/proc/scsi/
, which contains files specific to each SCSI controller using that driver. From the previous example, aic7xxx/
and megaraid/
directories are present, since two drivers are in use. The files in each of the directories typically contain an I/O address range, IRQ information, and statistics for the SCSI controller using that driver. Each controller can report a different type and amount of information. The Adaptec AIC-7880 Ultra SCSI host adapter's file in this example system produces the following output:
Adaptec AIC7xxx driver version: 5.1.20/3.2.4 Compile Options: TCQ Enabled By Default : Disabled AIC7XXX_PROC_STATS : Enabled AIC7XXX_RESET_DELAY : 5 Adapter Configuration: SCSI Adapter: Adaptec AIC-7880 Ultra SCSI host adapter Ultra Narrow Controller PCI MMAPed I/O Base: 0xfcffe000 Adapter SEEPROM Config: SEEPROM found and used. Adaptec SCSI BIOS: Enabled IRQ: 30 SCBs: Active 0, Max Active 1, Allocated 15, HW 16, Page 255 Interrupts: 33726 BIOS Control Word: 0x18a6 Adapter Control Word: 0x1c5f Extended Translation: Enabled Disconnect Enable Flags: 0x00ff Ultra Enable Flags: 0x0020 Tag Queue Enable Flags: 0x0000 Ordered Queue Tag Flags: 0x0000 Default Tag Queue Depth: 8 Tagged Queue By Device array for aic7xxx host instance 1: {255,255,255,255,255,255,255,255,255,255,255,255,255,255,255,255} Actual queue depth per device for aic7xxx host instance 1: {1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1} Statistics: (scsi1:0:5:0) Device using Narrow/Sync transfers at 20.0 MByte/sec, offset 15 Transinfo settings: current(12/15/0/0), goal(12/15/0/0), user(12/15/0/0) Total transfers 0 (0 reads and 0 writes) < 2K 2K+ 4K+ 8K+ 16K+ 32K+ 64K+ 128K+ Reads: 0 0 0 0 0 0 0 0 Writes: 0 0 0 0 0 0 0 0 (scsi1:0:6:0) Device using Narrow/Sync transfers at 10.0 MByte/sec, offset 15 Transinfo settings: current(25/15/0/0), goal(12/15/0/0), user(12/15/0/0) Total transfers 132 (0 reads and 132 writes) < 2K 2K+ 4K+ 8K+ 16K+ 32K+ 64K+ 128K+ Reads: 0 0 0 0 0 0 0 0 Writes: 0 0 0 1 131 0 0 0
/proc/sys/
directory is different from others in /proc
because it not only provides information about the system but also allows the system administrator to immediately enable and disable kernel features.
Warning
/proc/sys/
directory. Changing the wrong setting may render the kernel unstable, requiring a system reboot.
/proc/sys/
.
-l
option at the shell prompt. If the file is writable, it may be used to configure the kernel. For example, a partial listing of /proc/sys/fs
looks like the following:
-r--r--r-- 1 root root 0 May 10 16:14 dentry-state -rw-r--r-- 1 root root 0 May 10 16:14 dir-notify-enable -rw-r--r-- 1 root root 0 May 10 16:14 file-max -r--r--r-- 1 root root 0 May 10 16:14 file-nr
dir-notify-enable
and file-max
can be written to and, therefore, can be used to configure the kernel. The other files only provide feedback on current settings.
/proc/sys/
file is done by echoing the new value into the file. For example, to enable the System Request Key on a running kernel, type the command:
echo 1 > /proc/sys/kernel/sysrq
sysrq
from 0
(off) to 1
(on).
/proc/sys/
configuration files contain more than one value. To correctly send new values to them, place a space character between each value passed with the echo
command, such as is done in this example:
echo 4 2 45 > /proc/sys/kernel/acct
Note
echo
command disappear when the system is restarted. To make configuration changes take effect after the system is rebooted, refer to Section 2.4, “Using the sysctl Command”.
/proc/sys/
directory contains several subdirectories controlling different aspects of a running kernel.
cdrom/
and raid/
. Customized kernels can have other directories, such as parport/
, which provides the ability to share one parallel port between multiple device drivers.
cdrom/
directory contains a file called info
, which reveals a number of important CD-ROM parameters:
CD-ROM information, Id: cdrom.c 3.20 2003/12/17 drive name: hdc drive speed: 48 drive # of slots: 1 Can close tray: 1 Can open tray: 1 Can lock tray: 1 Can change speed: 1 Can select disk: 0 Can read multisession: 1 Can read MCN: 1 Reports media changed: 1 Can play audio: 1 Can write CD-R: 0 Can write CD-RW: 0 Can read DVD: 0 Can write DVD-R: 0 Can write DVD-RAM: 0 Can read MRW: 0 Can write MRW: 0 Can write RAM: 0
/proc/sys/dev/cdrom
, such as autoclose
and checkmedia
, can be used to control the system's CD-ROM. Use the echo
command to enable or disable these features.
/proc/sys/dev/raid/
directory becomes available with at least two files in it: speed_limit_min
and speed_limit_max
. These settings determine the acceleration of RAID devices for I/O intensive tasks, such as resyncing the disks.
binfmt_misc/
directory is used to provide kernel support for miscellaneous binary formats.
/proc/sys/fs/
include:
dentry-state
— Provides the status of the directory cache. The file looks similar to the following:
57411 52939 45 0 0 0
file-max
— Lists the maximum number of file handles that the kernel allocates. Raising the value in this file can resolve errors caused by a lack of available file handles.
file-nr
— Lists the number of allocated file handles, used file handles, and the maximum number of file handles.
overflowgid
and overflowuid
— Defines the fixed group ID and user ID, respectively, for use with file systems that only support 16-bit group and user IDs.
acct
— Controls the suspension of process accounting based on the percentage of free space available on the file system containing the log. By default, the file looks like the following:
4 2 30
ctrl-alt-del
— Controls whether Ctrl+Alt+Delete gracefully restarts the computer using init
(0
) or forces an immediate reboot without syncing the dirty buffers to disk (1
).
domainname
— Configures the system domain name, such as example.com
.
exec-shield
— Configures the Exec Shield feature of the kernel. Exec Shield provides protection against certain types of buffer overflow attacks.
0
— Disables Exec Shield.
1
— Enables Exec Shield. This is the default value.
Important
hostname
— Configures the system host name, such as www.example.com
.
hotplug
— Configures the utility to be used when a configuration change is detected by the system. This is primarily used with USB and Cardbus PCI. The default value of /sbin/hotplug
should not be changed unless testing a new program to fulfill this role.
modprobe
— Sets the location of the program used to load kernel modules. The default value is /sbin/modprobe
which means kmod
calls it to load the module when a kernel thread calls kmod
.
msgmax
— Sets the maximum size of any message sent from one process to another and is set to 8192
bytes by default. Be careful when raising this value, as queued messages between processes are stored in non-swappable kernel memory. Any increase in msgmax
would increase RAM requirements for the system.
msgmnb
— Sets the maximum number of bytes in a single message queue. The default is 16384
.
msgmni
— Sets the maximum number of message queue identifiers. The default is 4008
.
osrelease
— Lists the Linux kernel release number. This file can only be altered by changing the kernel source and recompiling.
ostype
— Displays the type of operating system. By default, this file is set to Linux
, and this value can only be changed by changing the kernel source and recompiling.
overflowgid
and overflowuid
— Defines the fixed group ID and user ID, respectively, for use with system calls on architectures that only support 16-bit group and user IDs.
panic
— Defines the number of seconds the kernel postpones rebooting when the system experiences a kernel panic. By default, the value is set to 0
, which disables automatic rebooting after a panic.
printk
— This file controls a variety of settings related to printing or logging error messages. Each error message reported by the kernel has a loglevel associated with it that defines the importance of the message. The loglevel values break down in this order:
0
— Kernel emergency. The system is unusable.
1
— Kernel alert. Action must be taken immediately.
2
— Condition of the kernel is considered critical.
3
— General kernel error condition.
4
— General kernel warning condition.
5
— Kernel notice of a normal but significant condition.
6
— Kernel informational message.
7
— Kernel debug-level messages.
printk
file:
6 4 1 7
random/
directory — Lists a number of values related to generating random numbers for the kernel.
sem
— Configures semaphore settings within the kernel. A semaphore is a System V IPC object that is used to control utilization of a particular process.
shmall
— Sets the total amount of shared memory that can be used at one time on the system, in bytes. By default, this value is 2097152
.
shmmax
— Sets the largest shared memory segment size allowed by the kernel. By default, this value is 33554432
. However, the kernel supports much larger values than this.
shmmni
— Sets the maximum number of shared memory segments for the whole system. By default, this value is 4096
.
sysrq
— Activates the System Request Key, if this value is set to anything other than zero (0
), the default.
r
— Disables raw mode for the keyboard and sets it to XLATE (a limited keyboard mode which does not recognize modifiers such as Alt, Ctrl, or Shift for all keys).
k
— Kills all processes active in a virtual console. Also called Secure Access Key (SAK), it is often used to verify that the login prompt is spawned from init
and not a trojan copy designed to capture usernames and passwords.
b
— Reboots the kernel without first unmounting file systems or syncing disks attached to the system.
c
— Crashes the system without first unmounting file systems or syncing disks attached to the system.
o
— Shuts off the system.
s
— Attempts to sync disks attached to the system.
u
— Attempts to unmount and remount all file systems as read-only.
p
— Outputs all flags and registers to the console.
t
— Outputs a list of processes to the console.
m
— Outputs memory statistics to the console.
0
through 9
— Sets the log level for the console.
e
— Kills all processes except init
using SIGTERM.
i
— Kills all processes except init
using SIGKILL.
l
— Kills all processes using SIGKILL (including init
). The system is unusable after issuing this System Request Key code.
h
— Displays help text.
Warning
/usr/share/doc/kernel-doc-kernel_version/Documentation/sysrq.txt
file for more information about the System Request Key.
tainted
— Indicates whether a non-GPL module is loaded.
0
— No non-GPL modules are loaded.
1
— At least one module without a GPL license (including modules with no license) is loaded.
2
— At least one module was force-loaded with the command insmod -f
.
threads-max
— Sets the maximum number of threads to be used by the kernel, with a default value of 2048
.
version
— Displays the date and time the kernel was last compiled. The first field in this file, such as #3
, relates to the number of times a kernel was built from the source base.
ethernet/
, ipv4/
, ipx/
, and ipv6/
. By altering the files within these directories, system administrators are able to adjust the network configuration on a running system.
/proc/sys/net/
directories are discussed.
/proc/sys/net/core/
directory contains a variety of settings that control the interaction between the kernel and networking layers. The most important of these files are:
message_burst
— Sets the amount of time in tenths of a second required to write a new warning message. This setting is used to mitigate Denial of Service (DoS) attacks. The default setting is 10
.
message_cost
— Sets a cost on every warning message. The higher the value of this file (default of 5
), the more likely the warning message is ignored. This setting is used to mitigate DoS attacks.
message_burst
and message_cost
are designed to be modified based on the system's acceptable risk versus the need for comprehensive logging.
netdev_max_backlog
— Sets the maximum number of packets allowed to queue when a particular interface receives packets faster than the kernel can process them. The default value for this file is 1000
.
optmem_max
— Configures the maximum ancillary buffer size allowed per socket.
rmem_default
— Sets the receive socket buffer default size in bytes.
rmem_max
— Sets the receive socket buffer maximum size in bytes.
wmem_default
— Sets the send socket buffer default size in bytes.
wmem_max
— Sets the send socket buffer maximum size in bytes.
/proc/sys/net/ipv4/
directory contains additional networking settings. Many of these settings, used in conjunction with one another, are useful in preventing attacks on the system or when using the system to act as a router.
Warning
/proc/sys/net/ipv4/
directory:
icmp_echo_ignore_all
and icmp_echo_ignore_broadcasts
— Allows the kernel to ignore ICMP ECHO packets from every host or only those originating from broadcast and multicast addresses, respectively. A value of 0
allows the kernel to respond, while a value of 1
ignores the packets.
ip_default_ttl
— Sets the default Time To Live (TTL), which limits the number of hops a packet may make before reaching its destination. Increasing this value can diminish system performance.
ip_forward
— Permits interfaces on the system to forward packets to one other. By default, this file is set to 0
. Setting this file to 1
enables network packet forwarding.
ip_local_port_range
— Specifies the range of ports to be used by TCP or UDP when a local port is needed. The first number is the lowest port to be used and the second number specifies the highest port. Any systems that expect to require more ports than the default 1024 to 4999 should use a range from 32768 to 61000.
tcp_syn_retries
— Provides a limit on the number of times the system re-transmits a SYN packet when attempting to make a connection.
tcp_retries1
— Sets the number of permitted re-transmissions attempting to answer an incoming connection. Default of 3
.
tcp_retries2
— Sets the number of permitted re-transmissions of TCP packets. Default of 15
.
/usr/share/doc/kernel-doc-kernel_version/Documentation/networking/ip-sysctl.txt
contains a complete list of files and options available in the /proc/sys/net/ipv4/
directory.
/proc/sys/net/ipv4/
directory and each covers a different aspect of the network stack. The /proc/sys/net/ipv4/conf/
directory allows each system interface to be configured in different ways, including the use of default settings for unconfigured devices (in the /proc/sys/net/ipv4/conf/default/
subdirectory) and settings that override all special configurations (in the /proc/sys/net/ipv4/conf/all/
subdirectory).
/proc/sys/net/ipv4/neigh/
directory contains settings for communicating with a host directly connected to the system (called a network neighbor) and also contains different settings for systems more than one hop away.
/proc/sys/net/ipv4/route/
. Unlike conf/
and neigh/
, the /proc/sys/net/ipv4/route/
directory contains specifications that apply to routing with any interfaces on the system. Many of these settings, such as max_size
, max_delay
, and min_delay
, relate to controlling the size of the routing cache. To clear the routing cache, write any value to the flush
file.
/usr/share/doc/kernel-doc-kernel_version/Documentation/filesystems/proc.txt
file.
/proc/sys/vm/
directory:
block_dump
— Configures block I/O debugging when enabled. All read/write and block dirtying operations done to files are logged accordingly. This can be useful if diagnosing disk spin up and spin downs for laptop battery conservation. All output when block_dump
is enabled can be retrieved via dmesg
. The default value is 0
.
Note
block_dump
is enabled at the same time as kernel debugging, it is prudent to stop the klogd
daemon, as it generates erroneous disk activity caused by block_dump
.
dirty_background_ratio
— Starts background writeback of dirty data at this percentage of total memory, via a pdflush daemon. The default value is 10
.
dirty_expire_centisecs
— Defines when dirty in-memory data is old enough to be eligible for writeout. Data which has been dirty in-memory for longer than this interval is written out next time a pdflush daemon wakes up. The default value is 3000
, expressed in hundredths of a second.
dirty_ratio
— Starts active writeback of dirty data at this percentage of total memory for the generator of dirty data, via pdflush. The default value is 20
.
dirty_writeback_centisecs
— Defines the interval between pdflush daemon wakeups, which periodically writes dirty in-memory data out to disk. The default value is 500
, expressed in hundredths of a second.
laptop_mode
— Minimizes the number of times that a hard disk needs to spin up by keeping the disk spun down for as long as possible, therefore conserving battery power on laptops. This increases efficiency by combining all future I/O processes together, reducing the frequency of spin ups. The default value is 0
, but is automatically enabled in case a battery on a laptop is used.
/usr/share/doc/kernel-doc-kernel_version/Documentation/laptop-mode.txt
file.
max_map_count
— Configures the maximum number of memory map areas a process may have. In most cases, the default value of 65536
is appropriate.
min_free_kbytes
— Forces the Linux VM (virtual memory manager) to keep a minimum number of kilobytes free. The VM uses this number to compute a pages_min
value for each lowmem
zone in the system. The default value is in respect to the total memory on the machine.
nr_hugepages
— Indicates the current number of configured hugetlb
pages in the kernel.
/usr/share/doc/kernel-doc-kernel_version/Documentation/vm/hugetlbpage.txt
file.
nr_pdflush_threads
— Indicates the number of pdflush daemons that are currently running. This file is read-only, and should not be changed by the user. Under heavy I/O loads, the default value of two is increased by the kernel.
overcommit_memory
— Configures the conditions under which a large memory request is accepted or denied. The following three modes are available:
0
— The kernel performs heuristic memory over commit handling by estimating the amount of memory available and failing requests that are blatantly invalid. Unfortunately, since memory is allocated using a heuristic rather than a precise algorithm, this setting can sometimes allow available memory on the system to be overloaded. This is the default setting.
1
— The kernel performs no memory over commit handling. Under this setting, the potential for memory overload is increased, but so is performance for memory intensive tasks (such as those executed by some scientific software).
2
— The kernel fails any request for memory that would cause the total address space to exceed the sum of the allocated swap space and the percentage of physical RAM specified in /proc/sys/vm/overcommit_ratio
. This setting is best for those who desire less risk of memory overcommitment.
Note
overcommit_ratio
— Specifies the percentage of physical RAM considered when /proc/sys/vm/overcommit_memory
is set to 2
. The default value is 50
.
page-cluster
— Sets the number of pages read in a single attempt. The default value of 3
, which actually relates to 16 pages, is appropriate for most systems.
swappiness
— Determines how much a machine should swap. The higher the value, the more swapping occurs. The default value, as a percentage, is set to 60
.
/usr/share/doc/kernel-doc-kernel_version/Documentation/
directory, which contains additional information.
msg
), semaphores (sem
), and shared memory (shm
).
drivers
file is a list of the current tty devices in use, as in the following example:
serial /dev/cua 5 64-127 serial:callout serial /dev/ttyS 4 64-127 serial pty_slave /dev/pts 136 0-255 pty:slave pty_master /dev/ptm 128 0-255 pty:master pty_slave /dev/ttyp 3 0-255 pty:slave pty_master /dev/pty 2 0-255 pty:master /dev/vc/0 /dev/vc/0 4 0 system:vtmaster /dev/ptmx /dev/ptmx 5 2 system /dev/console /dev/console 5 1 system:console /dev/tty /dev/tty 5 0 system:/dev/tty unknown /dev/vc/%d 4 1-63 console
/proc/tty/driver/serial
file lists the usage statistics and status of each of the serial tty lines.
/proc/sys/vm/panic_on_oom
. When set to 1
the kernel will panic on OOM. A setting of 0
instructs the kernel to call a function named oom_killer
on an OOM. Usually, oom_killer
can kill rogue processes and the system will survive.
/proc/sys/vm/panic_on_oom
.
# cat /proc/sys/vm/panic_on_oom 1 # echo 0 > /proc/sys/vm/panic_on_oom # cat /proc/sys/vm/panic_on_oom 0
oom_killer
score. In /proc/PID/
there are two tools labeled oom_adj
and oom_score
. Valid scores for oom_adj
are in the range -16 to +15. To see the current oom_killer
score, view the oom_score
for the process. oom_killer
will kill processes with the highest scores first.
oom_killer
will kill it.
# cat /proc/12465/oom_score 79872 # echo -5 > /proc/12465/oom_adj # cat /proc/12465/oom_score 78
oom_killer
for that process. In the example below, oom_score
returns a value of 0, indicating that this process would not be killed.
# cat /proc/12465/oom_score 78 # echo -17 > /proc/12465/oom_adj # cat /proc/12465/oom_score 0
badness()
is used to determine the actual score for each process. This is done by adding up 'points' for each examined process. The process scoring is done in the following way:
CAP_SYS_ADMIN
and CAP_SYS_RAWIO
capabilities have their scores reduced.
oom_adj
file.
oom_score
value will most probably be a non-privileged, recently started process that, along with its children, uses a large amount of memory, has been 'niced', and handles no raw I/O.
/sbin/sysctl
command is used to view, set, and automate kernel settings in the /proc/sys/
directory.
/proc/sys/
directory, type the /sbin/sysctl -a
command as root. This creates a large, comprehensive list, a small portion of which looks something like the following:
net.ipv4.route.min_delay = 2 kernel.sysrq = 0 kernel.sem = 250 32000 32 128
/proc/sys/net/ipv4/route/min_delay
file is listed as net.ipv4.route.min_delay
, with the directory slashes replaced by dots and the proc.sys
portion assumed.
sysctl
command can be used in place of echo
to assign values to writable files in the /proc/sys/
directory. For example, instead of using the command
echo 1 > /proc/sys/kernel/sysrq
sysctl
command as follows:
sysctl -w kernel.sysrq="1" kernel.sysrq = 1
/proc/sys/
is helpful during testing, this method does not work as well on a production system as special settings within /proc/sys/
are lost when the machine is rebooted. To preserve custom settings, add them to the /etc/sysctl.conf
file.
init
program runs the /etc/rc.d/rc.sysinit
script. This script contains a command to execute sysctl
using /etc/sysctl.conf
to determine the values passed to the kernel. Any values added to /etc/sysctl.conf
therefore take effect each time the system boots.
proc
file system.
proc
file system is installed on the system by default.
/usr/share/doc/kernel-doc-kernel_version/Documentation/filesystems/proc.txt
— Contains assorted, but limited, information about all aspects of the /proc
directory.
/usr/share/doc/kernel-doc-kernel_version/Documentation/sysrq.txt
— An overview of System Request Key options.
/usr/share/doc/kernel-doc-kernel_version/Documentation/sysctl/
— A directory containing a variety of sysctl
tips, including modifying values that concern the kernel (kernel.txt
), accessing file systems (fs.txt
), and virtual memory use (vm.txt
).
/usr/share/doc/kernel-doc-kernel_version/Documentation/networking/ip-sysctl.txt
— A detailed overview of IP networking options.
/etc/sysconfig/
directory, their function, and their contents. The information in this chapter is not intended to be complete, as many of these files have a variety of options that are only used in very specific or rare circumstances.
Note
/etc/sysconfig/
directory depends on the programs you have installed on your machine. To find the name of the package the configuration file belongs to, type the following at a shell prompt as root
:
yum provides /etc/sysconfig/file_name
/etc/sysconfig/
directory.
/etc/sysconfig/arpwatch
file is used to pass arguments to the arpwatch
daemon at boot time. By default, it contains the following option:
OPTIONS=value
arpwatch
daemon. For example:
OPTIONS="-u arpwatch -e root -s 'root (Arpwatch)'"
/etc/sysconfig/authconfig
file sets the authorization to be used on the host. By default, it contains the following options:
USEMKHOMEDIR=boolean
yes
) or disable (no
) creating a home directory for a user on the first login. For example:
USEMKHOMEDIR=no
USEPAMACCESS=boolean
yes
) or disable (no
) the PAM authentication. For example:
USEPAMACCESS=no
USESSSDAUTH=boolean
yes
) or disable (no
) the SSSD authentication. For example:
USESSSDAUTH=no
USESHADOW=boolean
yes
) or disable (no
) shadow passwords. For example:
USESHADOW=yes
USEWINBIND=boolean
yes
) or disable (no
) using Winbind for user account configuration. For example:
USEWINBIND=no
USEDB=boolean
yes
) or disable (no
) the FAS authentication. For example:
USEDB=no
USEFPRINTD=boolean
yes
) or disable (no
) the fingerprint authentication. For example:
USEFPRINTD=yes
FORCESMARTCARD=boolean
yes
) or disable (no
) enforcing the smart card authentication. For example:
FORCESMARTCARD=no
PASSWDALGORITHM=value
bigcrypt
, descrypt
, md5
, sha256
, or sha512
. For example:
PASSWDALGORITHM=sha512
USELDAPAUTH=boolean
yes
) or disable (no
) the LDAP authentication. For example:
USELDAPAUTH=no
USELOCAUTHORIZE=boolean
yes
) or disable (no
) the local authorization for local users. For example:
USELOCAUTHORIZE=yes
USECRACKLIB=boolean
yes
) or disable (no
) using the CrackLib. For example:
USECRACKLIB=yes
USEWINBINDAUTH=boolean
yes
) or disable (no
) the Winbind authentication. For example:
USEWINBINDAUTH=no
USESMARTCARD=boolean
yes
) or disable (no
) the smart card authentication. For example:
USESMARTCARD=no
USELDAP=boolean
yes
) or disable (no
) using LDAP for user account configuration. For example:
USELDAP=no
USENIS=boolean
yes
) or disable (no
) using NIS for user account configuration. For example:
USENIS=no
USEKERBEROS=boolean
yes
) or disable (no
) the Kerberos authentication. For example:
USEKERBEROS=no
USESYSNETAUTH=boolean
yes
) or disable (no
) authenticating system accounts with network services. For example:
USESYSNETAUTH=no
USESMBAUTH=boolean
yes
) or disable (no
) the SMB authentication. For example:
USESMBAUTH=no
USESSSD=boolean
yes
) or disable (no
) using SSSD for obtaining user information. For example:
USESSSD=no
USEHESIOD=boolean
yes
) or disable (no
) using the Hesoid name service. For example:
USEHESIOD=no
/etc/sysconfig/autofs
file defines custom options for the automatic mounting of devices. This file controls the operation of the automount daemons, which automatically mount file systems when you use them and unmount them after a period of inactivity. File systems can include network file systems, CD-ROM drives, diskettes, and other media.
MASTER_MAP_NAME=value
MASTER_MAP_NAME="auto.master"
TIMEOUT=value
TIMEOUT=300
NEGATIVE_TIMEOUT=value
NEGATIVE_TIMEOUT=60
MOUNT_WAIT=value
mount
. For example:
MOUNT_WAIT=-1
UMOUNT_WAIT=value
umount
. For example:
UMOUNT_WAIT=12
BROWSE_MODE=boolean
yes
) or disable (no
) browsing the maps. For example:
BROWSE_MODE="no"
MOUNT_NFS_DEFAULT_PROTOCOL=value
mount.nfs
. For example:
MOUNT_NFS_DEFAULT_PROTOCOL=4
APPEND_OPTIONS=boolean
yes
) or disable (no
) appending the global options instead of replacing them. For example:
APPEND_OPTIONS="yes"
LOGGING=value
none
, verbose
, or debug
. For example:
LOGGING="none"
LDAP_URI=value
protocol://server
. For example:
LDAP_URI="ldaps://ldap.example.com/"
LDAP_TIMEOUT=value
LDAP_TIMEOUT=-1
LDAP_NETWORK_TIMEOUT=value
LDAP_NETWORK_TIMEOUT=8
SEARCH_BASE=value
SEARCH_BASE=""
AUTH_CONF_FILE=value
AUTH_CONF_FILE="/etc/autofs_ldap_auth.conf"
MAP_HASH_TABLE_SIZE=value
MAP_HASH_TABLE_SIZE=1024
USE_MISC_DEVICE=boolean
yes
) or disable (no
) using the autofs miscellaneous device. For example:
USE_MISC_DEVICE="yes"
OPTIONS=value
OPTIONS=""
/etc/sysconfig/clock
file controls the interpretation of values read from the system hardware clock. It is used by the Date/Time Properties tool, and should not be edited by hand. By default, it contains the following option:
ZONE=value
/usr/share/zoneinfo
that /etc/localtime
is a copy of. For example:
ZONE="Europe/Prague"
/etc/sysconfig/dhcpd
file is used to pass arguments to the dhcpd
daemon at boot time. By default, it contains the following options:
DHCPDARGS=value
dhcpd
daemon. For example:
DHCPDARGS=
/etc/sysconfig/firstboot
file defines whether to run the firstboot
utility. By default, it contains the following option:
RUN_FIRSTBOOT=boolean
YES
) or disable (NO
) running the firstboot
program. For example:
RUN_FIRSTBOOT=NO
init
program calls the /etc/rc.d/init.d/firstboot
script, which looks for the /etc/sysconfig/firstboot
file. If this file does not contain the RUN_FIRSTBOOT=NO
option, the firstboot
program is run, guiding a user through the initial configuration of the system.
Note
firstboot
program the next time the system boots, change the value of RUN_FIRSTBOOT
option to YES
, and type the following at a shell prompt as root
:
systemctl enable firstboot-graphical.service
/etc/sysconfig/i18n
configuration file defines the default language, any supported languages, and the default system font. By default, it contains the following options:
LANG=value
LANG="en_US.UTF-8"
SUPPORTED=value
SUPPORTED="en_US.UTF-8:en_US:en"
SYSFONT=value
SYSFONT="latarcyrheb-sun16"
/etc/sysconfig/init
file controls how the system appears and functions during the boot process. By default, it contains the following options:
BOOTUP=value
color
(the standard color boot display), verbose
(an old style display which provides more information), or anything else for the new style display, but without ANSI formatting. For example:
BOOTUP=color
RES_COL=value
RES_COL=60
MOVE_TO_COL=value
RES_COL
(see above). For example:
MOVE_TO_COL="echo -en \\033[${RES_COL}G"
SETCOLOR_SUCCESS=value
SETCOLOR_SUCCESS="echo -en \\033[0;32m"
SETCOLOR_FAILURE=value
SETCOLOR_FAILURE="echo -en \\033[0;31m"
SETCOLOR_WARNING=value
SETCOLOR_WARNING="echo -en \\033[0;33m"
SETCOLOR_NORMAL=value
SETCOLOR_NORMAL="echo -en \\033[0;39m"
LOGLEVEL=value
1
(kernel panics only) to 8
(everything, including the debugging information). For example:
LOGLEVEL=3
PROMPT=boolean
yes
) or disable (no
) the hotkey interactive startup. For example:
PROMPT=yes
AUTOSWAP=boolean
yes
) or disable (no
) probing for devices with swap signatures. For example:
AUTOSWAP=no
ACTIVE_CONSOLES=value
ACTIVE_CONSOLES=/dev/tty[1-6]
SINGLE=value
/sbin/sulogin
(a user will be prompted for a password to log in), or /sbin/sushell
(the user will be logged in directly). For example:
SINGLE=/sbin/sushell
/etc/sysconfig/ip6tables-config
file stores information used by the kernel to set up IPv6 packet filtering at boot time or whenever the ip6tables
service is started. Note that you should not modify it unless you are familiar with ip6tables
rules. By default, it contains the following options:
IP6TABLES_MODULES=value
IP6TABLES_MODULES="ip_nat_ftp ip_nat_irc"
IP6TABLES_MODULES_UNLOAD=boolean
yes
) or disable (no
) module unloading when the firewall is stopped or restarted. For example:
IP6TABLES_MODULES_UNLOAD="yes"
IP6TABLES_SAVE_ON_STOP=boolean
yes
) or disable (no
) saving the current firewall rules when the firewall is stopped. For example:
IP6TABLES_SAVE_ON_STOP="no"
IP6TABLES_SAVE_ON_RESTART=boolean
yes
) or disable (no
) saving the current firewall rules when the firewall is restarted. For example:
IP6TABLES_SAVE_ON_RESTART="no"
IP6TABLES_SAVE_COUNTER=boolean
yes
) or disable (no
) saving the rule and chain counters. For example:
IP6TABLES_SAVE_COUNTER="no"
IP6TABLES_STATUS_NUMERIC=boolean
yes
) or disable (no
) printing IP addresses and port numbers in a numeric format in the status output. For example:
IP6TABLES_STATUS_NUMERIC="yes"
IP6TABLES_STATUS_VERBOSE=boolean
yes
) or disable (no
) printing information about the number of packets and bytes in the status output. For example:
IP6TABLES_STATUS_VERBOSE="no"
IP6TABLES_STATUS_LINENUMBERS=boolean
yes
) or disable (no
) printing line numbers in the status output. For example:
IP6TABLES_STATUS_LINENUMBERS="yes"
Note
ip6tables
command. Once created, type the following at a shell prompt as root
:
service ip6tables save
/etc/sysconfig/ip6tables
file. Once this file exists, any firewall rules saved in it persist through a system reboot or a service restart.
/etc/sysconfig/keyboard
file controls the behavior of the keyboard. By default, it contains the following options:
KEYTABLE=value
/lib/kbd/keymaps/i386/
directory, and branch into different keyboard layouts from there, all labeled value.kmap.gz
. The first file name that matches the KEYTABLE
setting is used. For example:
KEYTABLE="us"
MODEL=value
MODEL="pc105+inet"
LAYOUT=value
LAYOUT="us"
KEYBOARDTYPE=value
pc
(a PS/2 keyboard), or sun
(a Sun keyboard). For example:
KEYBOARDTYPE="pc"
/etc/sysconfig/ldap
file holds the basic configuration for the LDAP server. By default, it contains the following options:
SLAPD_OPTIONS=value
slapd
daemon. For example:
SLAPD_OPTIONS="-4"
SLURPD_OPTIONS=value
slurpd
daemon. For example:
SLURPD_OPTIONS=""
SLAPD_LDAP=boolean
yes
) or disable (no
) using the LDAP over TCP (that is, ldap:///
). For example:
SLAPD_LDAP="yes"
SLAPD_LDAPI=boolean
yes
) or disable (no
) using the LDAP over IPC (that is, ldapi:///
). For example:
SLAPD_LDAPI="no"
SLAPD_LDAPS=boolean
yes
) or disable (no
) using the LDAP over TLS (that is, ldaps:///
). For example:
SLAPD_LDAPS="no"
SLAPD_URLS=value
SLAPD_URLS="ldapi:///var/lib/ldap_root/ldapi ldapi:/// ldaps:///"
SLAPD_SHUTDOWN_TIMEOUT=value
slapd
to shut down. For example:
SLAPD_SHUTDOWN_TIMEOUT=3
SLAPD_ULIMIT_SETTINGS=value
ulimit
before the slapd
daemon is started. For example:
SLAPD_ULIMIT_SETTINGS=""
/etc/sysconfig/named
file is used to pass arguments to the named
daemon at boot time. By default, it contains the following options:
ROOTDIR=value
named
daemon runs. The value has to be a full directory path. For example:
ROOTDIR="/var/named/chroot"
info chroot
at a shell prompt for more information).
OPTIONS=value
named
. For example:
OPTIONS="-6"
-t
option. Instead, use ROOTDIR
as described above.
KEYTAB_FILE=value
KEYTAB_FILE="/etc/named.keytab"
/etc/sysconfig/network
file is used to specify information about the desired network configuration. By default, it contains the following options:
NETWORKING=boolean
yes
) or disable (no
) the networking. For example:
NETWORKING=yes
HOSTNAME=value
HOSTNAME=penguin.example.com
GATEWAY=value
GATEWAY=192.168.1.0
Warning
/etc/sysconfig/ntpd
file is used to pass arguments to the ntpd
daemon at boot time. By default, it contains the following option:
OPTIONS=value
ntpd
. For example:
OPTIONS="-u ntp:ntp -p /var/run/ntpd.pid -g"
/etc/sysconfig/quagga
file holds the basic configuration for Quagga daemons. By default, it contains the following options:
QCONFDIR=value
QCONFDIR="/etc/quagga"
BGPD_OPTS=value
bgpd
daemon. For example:
BGPD_OPTS="-A 127.0.0.1 -f ${QCONFDIR}/bgpd.conf"
OSPF6D_OPTS=value
ospf6d
daemon. For example:
OSPF6D_OPTS="-A ::1 -f ${QCONFDIR}/ospf6d.conf"
OSPFD_OPTS=value
ospfd
daemon. For example:
OSPFD_OPTS="-A 127.0.0.1 -f ${QCONFDIR}/ospfd.conf"
RIPD_OPTS=value
ripd
daemon. For example:
RIPD_OPTS="-A 127.0.0.1 -f ${QCONFDIR}/ripd.conf"
RIPNGD_OPTS=value
ripngd
daemon. For example:
RIPNGD_OPTS="-A ::1 -f ${QCONFDIR}/ripngd.conf"
ZEBRA_OPTS=value
zebra
daemon. For example:
ZEBRA_OPTS="-A 127.0.0.1 -f ${QCONFDIR}/zebra.conf"
ISISD_OPTS=value
isisd
daemon. For example:
ISISD_OPTS="-A ::1 -f ${QCONFDIR}/isisd.conf"
WATCH_OPTS=value
watchquagga
daemon. For example:
WATCH_OPTS="-Az -b_ -r/sbin/service_%s_restart -s/sbin/service_%s_start -k/sbin/service_%s_stop"
WATCH_DAEMONS=value
WATCH_DAEMONS="zebra bgpd ospfd ospf6d ripd ripngd"
/etc/sysconfig/radvd
file is used to pass arguments to the radvd
daemon at boot time. By default, it contains the following option:
OPTIONS=value
radvd
daemon. For example:
OPTIONS="-u radvd"
/etc/sysconfig/samba
file is used to pass arguments to the Samba daemons at boot time. By default, it contains the following options:
SMBDOPTIONS=value
smbd
. For example:
SMBDOPTIONS="-D"
NMBDOPTIONS=value
nmbd
. For example:
NMBDOPTIONS="-D"
WINBINDOPTIONS=value
winbindd
. For example:
WINBINDOPTIONS=""
/etc/sysconfig/saslauthd
file is used to control which arguments are passed to saslauthd
, the SASL authentication server. By default, it contains the following options:
SOCKETDIR=value
saslauthd
's listening socket. For example:
SOCKETDIR=/var/run/saslauthd
MECH=value
MECH=pam
DAEMONOPTS=value
daemon()
function that is used by the /etc/rc.d/init.d/saslauthd
init script to start the saslauthd
service. For example:
DAEMONOPTS="--user saslauth"
FLAGS=value
saslauthd
service. For example:
FLAGS=
/etc/sysconfig/selinux
file contains the basic configuration options for SELinux. It is a symbolic link to /etc/selinux/config
, and by default, it contains the following options:
SELINUX=value
enforcing
(the security policy is always enforced), permissive
(instead of enforcing the policy, appropriate warnings are displayed), or disabled
(no policy is used). For example:
SELINUX=enforcing
SELINUXTYPE=value
targeted
(the targeted processes are protected), or mls
(the Multi Level Security protection). For example:
SELINUXTYPE=targeted
/etc/sysconfig/sendmail
file is used to set the default values for the Sendmail application. By default, it contains the following values:
DAEMON=boolean
yes
) or disable (no
) running sendmail
as a daemon. For example:
DAEMON=yes
QUEUE=value
QUEUE=1h
/etc/sysconfig/spamassassin
file is used to pass arguments to the spamd
daemon (a daemonized version of SpamAssassin) at boot time. By default, it contains the following option:
SPAMDOPTIONS=value
spamd
daemon. For example:
SPAMDOPTIONS="-d -c -m5 -H"
/etc/sysconfig/squid
file is used to pass arguments to the squid
daemon at boot time. By default, it contains the following options:
SQUID_OPTS=value
squid
daemon. For example:
SQUID_OPTS=""
SQUID_SHUTDOWN_TIMEOUT=value
squid
daemon to shut down. For example:
SQUID_SHUTDOWN_TIMEOUT=100
SQUID_CONF=value
SQUID_CONF="/etc/squid/squid.conf"
/etc/sysconfig/system-config-users
file is the configuration file for the User Manager tool, and should not be edited by hand. By default, it contains the following options:
FILTER=boolean
true
) or disable (false
) filtering of system users. For example:
FILTER=true
ASSIGN_HIGHEST_UID=boolean
true
) or disable (false
) assigning the highest available UID to newly added users. For example:
ASSIGN_HIGHEST_UID=true
ASSIGN_HIGHEST_GID=boolean
true
) or disable (false
) assigning the highest available GID to newly added groups. For example:
ASSIGN_HIGHEST_GID=true
PREFER_SAME_UID_GID=boolean
true
) or disable (false
) using the same UID and GID for newly added users when possible. For example:
PREFER_SAME_UID_GID=true
/etc/sysconfig/vncservers
file configures the way the Virtual Network Computing (VNC) server starts up. By default, it contains the following options:
VNCSERVERS=value
display:username
pairs. For example:
VNCSERVERS="2:myusername"
VNCSERVERARGS[display]=value
VNCSERVERARGS[2]="-geometry 800x600 -nolisten tcp -localhost"
/etc/sysconfig/xinetd
file is used to pass arguments to the xinetd
daemon at boot time. By default, it contains the following options:
EXTRAOPTIONS=value
xinetd
. For example:
EXTRAOPTIONS=""
XINETD_LANG=value
xinetd
. Note that to remove locale information from the xinetd
environment, you can use an empty string (""
) or none
. For example:
XINETD_LANG="en_US"
xinetd
services, refer to the Fedora System Administrator's Guide.
/etc/sysconfig/
.
/etc/sysconfig/cbq/
/etc/sysconfig/networking/
system-config-network
), and its contents should not be edited manually. For more information about configuring network interfaces using graphical configuration tools, refer to the Fedora Networking Guide.
/etc/sysconfig/network-scripts/
ifcfg-eth0
for the eth0
Ethernet interface.
ifup
and ifdown
.
ifup-isdn
and ifdown-isdn
.
/etc/sysconfig/network-scripts/
directory, refer to the Fedora Networking Guide.
/etc/sysconfig/
directory. The following source contains more comprehensive information.
/usr/share/doc/initscripts/sysconfig.txt
— A more authoritative listing of the files found in the /etc/sysconfig/
directory and the configuration options available for them.
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