Topic 8

Dates: 3/8/2017
Start-up and Run Levels. Scheduled jobs (at, cron)
Linux System Administration


Exercises: admin commands to start/stop services


Systemd driven services
Available on Ubuntu 16.04 and RedHat 7
Command systemctl talks to systemd. To see all the services registered with systemd, run the following:

systemctl list-units --type service
To stop rsyslog services, run

systemctl stop rsyslog
To see the status of the service:

systemctl status rsyslog
Stop syslog.socket then rsyslog.service:

systemctl stop syslog.socket
systemctl stop rsyslog.service
To see the status of the service:

systemctl status rsyslog
To start the service and see its status:

systemctl start rsyslog
systemctl status rsyslog 

Legacy System V services
Used to be available on any Linux distro. Now they are provided within Systemd for backward compatibility.
The System V (non-event driven) service startup scripts are located in directory /etc/init.d. For example to stop and then start cups printing service, use the following

apt-get install cups
/etc/init.d/cups stop
/etc/init.d/cups start
/etc/init.d/cups status
Is the same as

service cups stop
service cups start
service cups status




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