The chkconfig command is used to view and edit a service to be on or off at a particular runlevel.
chkconfig is used by systems using init. systemctl is used by systems using systemd.
The ps command can be used to determine if your system is using init or systemd. If PID 1 is init, then you will use chkconfig.
UID PID PPID C STIME TTY TIME CMD root 1 0 0 Mar08 ? 00:00:01 /sbin/init
If PID 1 is systemd, then you will use systemctl.
ps -ef | head UID PID PPID C STIME TTY TIME CMD root 1 0 0 Mar01 ? 00:06:47 /usr/lib/systemd/systemd --switched-root --system --deserialize 22
The chkconfig command without any options can be used to determine if a service is on or off at a particular runlevel. If you are not familar with runlevels, check out our article on runlevels.
/sbin/chkconfig . . . netconsole 0:off 1:off 2:off 3:off 4:off 5:off 6:off network 0:off 1:off 2:on 3:on 4:on 5:on 6:off
The --list option can be used to only display a certain service.
/sbin/chkconfig --list network . . . network 0:off 1:off 2:on 3:on 4:on 5:on 6:off
If you attempt to list a service that is not in chkconfig, something like this will be displayed.
service httpd supports chkconfig, but it is not referenced in any runlevel (run 'chkconfig --add httpd')
chkconfig gets services from files in the /etc/rc.d/init.d directory. Here is an example of the content of a file.
#!/bin/bash # # chkconfig: 345 # description: start httpd # Source function library . /etc/rc.d/init.d/functions case $1 in start) /opt/apache/bin/apachectl -k start ;; stop) /opt/apache/bin/apachectl -k stop ;; *) echo "Usage $0 start|stop|restart" ;; esac
The --add option is used to add a service to chkconfig. In this example, the httpd service is added to chkconfig. By default, the service will be off at runlevels 0 1 2 6 and on at runlevels 3 4 5.
/sbin/chkconfig --add httpd
The --del option is used to delete a service from chkconfig. In this example, the httpd service is removed from chkconfig.
/sbin/chkconfig --del httpd
The chkconfig service_name on or chkconfig service_name off commands can be used to turn a service on or off. This will turn the service on or off at every runlevel. For example, to turn the HTTPD service on or off.
/sbin/chkconfig httpd on /sbin/chkconfig httpd off
To only change the runlevel status for certain runlevels, use the --level option.
/sbin/chkconfig httpd on --level 345
When using the chkconfig command to change the runlevel of a service, a file in the /etc/init.d/ directory will be updated to contain the new runlevel. For example, the prior commands turns on the HTTPD deamon for runlevels 3, 4, and 5. This command updates the /etc/init.d/httpd file to contain the following. Even though this line is commented out, this still turns on the HTTPD deamon for runlevels 3, 4, and 5.
#!/bin/sh . . . # chkconfig: 345 95 05