==== Basic usage ====

<code bash>
 systemctl start apache2
 systemctl stop apache2
 systemctl enable apache2
 systemctl disable apache2
 systemctl status apache2
</code>

==== networkd ====

Config files:

  /etc/systemd/network

  DNS=...
  DHCP=..
  Gateway=..
  Address=..
  Domains=..
  ...

Check **man systemd.network**

==== tmpfiles.d, /var/run persistency ====

With the adoption of systemd, there is now a centralized mechanism for the creation of temporary files and directories. A service wishing to use this method can remove mkdir commands in its own startup script and instead place a .conf file in **/etc/tmpfiles.d**, **/run/tmpfiles.d**, or **/usr/lib/tmpfiles.d**, with Ubuntu services seeming to prefer the last option.

The format of these files is the following:

<code bash>
  #Type Path        Mode UID  GID  Age Argument
  d     /run/user   0755 root root 10d -
  L     /tmp/foobar -    -    -    -   /dev/null
</code>

Further information can be found using **man tmpfiles.d**

==== Init scripts ====

Init scripts are located here:

  /etc/systemd/system/
  /lib/systemd/system/
  ...

Example init scripts:

<code bash>
[Unit]
Description=Calibre Server
After=network.target

StartLimitIntervalSec=500
StartLimitBurst=5

[Service]
Type=forking
PIDFile=/var/run/calibre-server.pid
Restart=on-failure
RestartSec=5s
ExecStart=/usr/bin/calibre-server \
        --daemonize \
        --port 32452 \
        --pidfile /run/calibre-server.pid \
    --enable-local-write \
    --log=/var/log/calibre.log \
        /home/calibre/db \
        /home/calibre/en \
        /home/calibre/romantikus \
        /home/calibre/paperbooks

[Install]
WantedBy=multi-user.target

</code>

<code bash>
[Unit]
Description=Calibre Book Importer
After=network.target calibre.service

[Service]
Type=oneshot
ExecStart=/home/calibre/import-books.sh
KillMode=mixed

[Install]
WantedBy=multi-user.target

</code>
=== Types ===
  * forking
  * oneshot
  * ...

  # TODO!!!

=== Reload init scripts config ===

  systemctl daemon-reload