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<html xmlns="http://www.w3.org/1999/xhtml"><head><title>systemd.special</title><meta name="generator" content="DocBook XSL Stylesheets V1.76.1"/></head><body><div class="refentry" title="systemd.special"><a id="systemd.special"/><div class="titlepage"/><div class="refnamediv"><h2>Name</h2><p>systemd.special — special systemd units</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><p><code class="filename">basic.target</code>,
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<code class="filename">ctrl-alt-del.target</code>,
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<code class="filename">dbus.service</code>,
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<code class="filename">default.target</code>,
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<code class="filename">display-manager.service</code>,
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<code class="filename">emergency.target</code>,
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<code class="filename">exit.service</code>,
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<code class="filename">graphical.target</code>,
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<code class="filename">halt.target</code>,
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<code class="filename">kbrequest.target</code>,
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<code class="filename">local-fs.target</code>,
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<code class="filename">local-fs-pre.target</code>,
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<code class="filename">mail-transfer-agent.target</code>,
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<code class="filename">multi-user.target</code>,
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<code class="filename">network.target</code>,
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<code class="filename">nss-lookup.target</code>,
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<code class="filename">poweroff.target</code>,
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<code class="filename">reboot.target</code>,
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<code class="filename">remote-fs.target</code>,
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<code class="filename">remote-fs-pre.target</code>,
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<code class="filename">rescue.target</code>,
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<code class="filename">rpcbind.target</code>,
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<code class="filename">runlevel2.target</code>,
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<code class="filename">runlevel3.target</code>,
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<code class="filename">runlevel4.target</code>,
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<code class="filename">runlevel5.target</code>,
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<code class="filename">shutdown.target</code>,
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<code class="filename">sigpwr.target</code>,
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<code class="filename">sockets.target</code>,
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<code class="filename">swap.target</code>,
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<code class="filename">sysinit.target</code>,
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<code class="filename">syslog.target</code>,
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<code class="filename">systemd-initctl.service</code>,
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<code class="filename">systemd-initctl.socket</code>,
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<code class="filename">systemd-stdout-syslog-bridge.service</code>,
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<code class="filename">systemd-stdout-syslog-bridge.socket</code>,
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<code class="filename">time-sync.target</code>,
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<code class="filename">umount.target</code></p></div><div class="refsect1" title="Description"><a id="id309514"/><h2>Description</h2><p>A few units are treated specially by
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systemd. They have special internal semantics and
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cannot be renamed.</p></div><div class="refsect1" title="Special System Units"><a id="id309526"/><h2>Special System Units</h2><div class="variablelist"><dl><dt><span class="term"><code class="filename">basic.target</code></span></dt><dd><p>A special target unit
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covering early boot-up.</p><p>systemd automatically
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adds dependencies of the types
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Requires and After for this
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target unit to all SysV
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service units configured for
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runlevel 1 to 5.</p><p>Usually this should pull-in
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all sockets, mount points,
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swap devices and other basic
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initialization necessary for
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daemons. Most normal daemons
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should have dependencies of
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type After and Requires on
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this unit.</p></dd><dt><span class="term"><code class="filename">ctrl-alt-del.target</code></span></dt><dd><p>systemd starts this
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Control+Alt+Del is pressed on
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the console. Usually this
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should be aliased (symlinked)
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<code class="filename">reboot.target</code>.</p></dd><dt><span class="term"><code class="filename">dbus.service</code></span></dt><dd><p>A special unit for the
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D-Bus system bus. As soon as
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this service is fully started
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up systemd will connect to it
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service.</p></dd><dt><span class="term"><code class="filename">default.target</code></span></dt><dd><p>The default unit systemd
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starts at bootup. Usually this
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should be aliased (symlinked)
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<code class="filename">multi-user.target</code>
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<code class="filename">graphical.target</code>.</p><p>The default unit systemd
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starts at bootup can be
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<code class="varname">systemd.unit=</code>
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kernel command line option.</p></dd><dt><span class="term"><code class="filename">display-manager.service</code></span></dt><dd><p>The display manager
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service. Usually this should
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be aliased (symlinked) to
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<code class="filename">xdm.service</code>
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or a similar display manager
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service.</p><p>systemd automatically
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adds dependencies of type
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After for this target unit to
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all SysV init script service
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units with a LSB header
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<code class="literal">$x-display-manager</code>
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facility, for compatibility
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with Debian.</p></dd><dt><span class="term"><code class="filename">emergency.target</code></span></dt><dd><p>A special target unit
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that starts an emergency
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console. This unit is supposed
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to be used with the kernel
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<code class="varname">systemd.unit=</code>
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and has otherwise little use.
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</p></dd><dt><span class="term"><code class="filename">graphical.target</code></span></dt><dd><p>A special target unit
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for setting up a graphical
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login screen. This pulls in
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<code class="filename">multi-user.target</code>.</p><p>Units that are needed
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for graphical login shall add
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Wants dependencies for their
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unit to this unit (or
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<code class="filename">multi-user.target</code>)
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during installation.</p></dd><dt><span class="term"><code class="filename">halt.target</code></span></dt><dd><p>A special target unit
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for shutting down and halting the system.</p><p>Applications wanting to
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halt the system should start
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this unit.</p></dd><dt><span class="term"><code class="filename">kbrequest.target</code></span></dt><dd><p>systemd starts this
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target whenever Alt+ArrowUp is
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pressed on the console. This
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is a good candidate to be
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aliased (symlinked) to
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<code class="filename">rescue.target</code>.</p></dd><dt><span class="term"><code class="filename">local-fs.target</code></span></dt><dd><p>systemd automatically
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adds dependencies of type
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After to all mount units that
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refer to local mount points
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for this target unit. In
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addition, systemd adds
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dependencies of type Wants to
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this target unit for those
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<code class="filename">/etc/fstab</code>
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<code class="option">auto</code> and
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<code class="option">comment=systemd.mount</code>
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mount options set.</p><p>systemd automatically
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adds dependencies of type
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After for this target unit to
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all SysV init script service
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units with an LSB header
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<code class="literal">$local_fs</code>
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facility.</p></dd><dt><span class="term"><code class="filename">local-fs-pre.target</code></span></dt><dd><p>This target unit is
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automatically ordered before
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all local mount points marked
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with <code class="option">auto</code>
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(see above). It can be used to
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execute certain units before
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all local mounts.</p></dd><dt><span class="term"><code class="filename">mail-transfer-agent.target</code></span></dt><dd><p>The mail transfer agent
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(MTA) service. Usually this
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should pull-in all units
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sending/receiving mails on the
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local host.</p><p>systemd automatically
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adds dependencies of type
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After for this target unit to
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all SysV init script service
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units with an LSB header
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<code class="literal">$mail-transfer-agent</code>
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<code class="literal">$mail-transport-agent</code>
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facilities, for compatibility
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with Debian.</p></dd><dt><span class="term"><code class="filename">multi-user.target</code></span></dt><dd><p>A special target unit
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for setting up a multi-user
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system (non-graphical). This
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<code class="filename">graphical.target</code>.</p><p>Units that are needed
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for a multi-user system shall
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add Wants dependencies to
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this unit for their unit during
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installation.</p></dd><dt><span class="term"><code class="filename">network.target</code></span></dt><dd><p>systemd automatically
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adds dependencies of type
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After for this target unit to
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all SysV init script service
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units with an LSB header
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<code class="literal">$network</code>
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facility.</p></dd><dt><span class="term"><code class="filename">nss-lookup.target</code></span></dt><dd><p>systemd automatically
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adds dependencies of type
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After for this target unit to
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all SysV init script service
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units with an LSB header
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<code class="literal">$named</code>
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facility.</p></dd><dt><span class="term"><code class="filename">poweroff.target</code></span></dt><dd><p>A special target unit
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for shutting down and powering off the system.</p><p>Applications wanting to
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power off the system should start
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this unit.</p><p><code class="filename">runlevel0.target</code>
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is an alias for this target
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unit, for compatibility with SysV.</p></dd><dt><span class="term"><code class="filename">reboot.target</code></span></dt><dd><p>A special target unit
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for shutting down and rebooting the system.</p><p>Applications wanting to
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reboot the system should start
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this unit.</p><p><code class="filename">runlevel6.target</code>
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is an alias for this target
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unit, for compatibility with SysV.</p></dd><dt><span class="term"><code class="filename">remote-fs.target</code></span></dt><dd><p>Similar to
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<code class="filename">local-fs.target</code>,
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points.</p><p>systemd automatically
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adds dependencies of type
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After for this target unit to
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all SysV init script service
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units with an LSB header
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<code class="literal">$remote_fs</code>
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facility.</p></dd><dt><span class="term"><code class="filename">remote-fs-pre.target</code></span></dt><dd><p>This target unit is
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automatically ordered before
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all remote mount points marked
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with <code class="option">auto</code>
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(see above). It can be used to
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execute certain units before
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all remote mounts.</p></dd><dt><span class="term"><code class="filename">rescue.target</code></span></dt><dd><p>A special target unit
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for setting up the base system
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and a rescue shell.</p><p><code class="filename">runlevel1.target</code>
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is an alias for this target
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unit, for compatibility with SysV.</p></dd><dt><span class="term"><code class="filename">rpcbind.target</code></span></dt><dd><p>systemd automatically
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adds dependencies of type
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After for this target unit to
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all SysV init script service
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units with an LSB header
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<code class="literal">$rpcbind</code>
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facility.</p></dd><dt><span class="term"><code class="filename">runlevel2.target</code></span></dt><dd><p>This is a target that is
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called whenever the SysV
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compatibility code asks for
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runlevel 2. It is a good idea
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to make this an alias for
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<code class="filename">multi-user.target</code>.</p></dd><dt><span class="term"><code class="filename">runlevel3.target</code></span></dt><dd><p>This is a target that is
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called whenever the SysV
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compatibility code asks for
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runlevel 3. It is a good idea
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to make this an alias for
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<code class="filename">multi-user.target</code>
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<code class="filename">graphical.target</code>.</p></dd><dt><span class="term"><code class="filename">runlevel4.target</code></span></dt><dd><p>This is a target that is
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called whenever the SysV
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compatibility code asks for
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runlevel 4. It is a good idea
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to make this an alias for
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<code class="filename">multi-user.target</code>
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<code class="filename">graphical.target</code>.</p></dd><dt><span class="term"><code class="filename">runlevel5.target</code></span></dt><dd><p>This is a target that is
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called whenever the SysV
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compatibility code asks for
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runlevel 5. It is a good idea
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to make this an alias for
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<code class="filename">multi-user.target</code>
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<code class="filename">graphical.target</code>.</p></dd><dt><span class="term"><code class="filename">shutdown.target</code></span></dt><dd><p>A special target unit
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that terminates the services
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on system shutdown.</p><p>Services that shall be
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terminated on system shutdown
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dependencies to this unit for
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their service unit, which is
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<code class="varname">DefaultDependencies=yes</code>
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is set (the default).</p><p>systemd automatically
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adds dependencies of type
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Conflicts to this target unit
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for all SysV init script
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service units that shall be
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terminated in SysV runlevels 0
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or 6.</p></dd><dt><span class="term"><code class="filename">sigpwr.target</code></span></dt><dd><p>A special target that is
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started when systemd receives
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the SIGPWR process signal,
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which is normally sent by the
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kernel or UPS daemons when
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power fails.</p></dd><dt><span class="term"><code class="filename">sockets.target</code></span></dt><dd><p>A special target unit
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that sets up all service
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sockets.</p><p>Services that can be
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socket-activated shall add
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Wants dependencies to this
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unit for their socket unit
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during installation.</p></dd><dt><span class="term"><code class="filename">swap.target</code></span></dt><dd><p>Similar to
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<code class="filename">local-fs.target</code>, but for swap
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files.</p></dd><dt><span class="term"><code class="filename">sysinit.target</code></span></dt><dd><p>A special target unit
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covering early boot-up scripts.</p><p>systemd automatically
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adds dependencies of the types
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Wants and After for all
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SysV service units configured
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for runlevels that are not 0
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to 6 to this target unit.
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This covers the special
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boot-up runlevels some
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distributions have, such as S
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or b.</p></dd><dt><span class="term"><code class="filename">syslog.target</code></span></dt><dd><p>systemd automatically
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adds dependencies of type
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After for this target unit to
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all SysV init script service
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units with an LSB header
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<code class="literal">$syslog</code>
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facility.</p></dd><dt><span class="term"><code class="filename">systemd-initctl.service</code></span></dt><dd><p>This provides
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compatibility with the SysV
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/dev/initctl file system FIFO
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for communication with the
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init system.</p><p>This is a
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socket-activated service, see
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<code class="filename">system-initctl.socket</code>.</p></dd><dt><span class="term"><code class="filename">systemd-initctl.socket</code></span></dt><dd><p>Socket activation unit
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<code class="filename">system-initctl.service</code>.</p></dd><dt><span class="term"><code class="filename">systemd-stdout-syslog-bridge.service</code></span></dt><dd><p>This is internally used
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by systemd to provide syslog
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logging to the processes it
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maintains.</p><p>This is a
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socket-activated service, see
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<code class="filename">system-stdout-syslog-bridge.socket</code>.</p></dd><dt><span class="term"><code class="filename">systemd-stdout-syslog-bridge.socket</code></span></dt><dd><p>Socket activation unit
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<code class="filename">system-stdout-syslog-bridge.service</code>. systemd
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will automatically add
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dependencies of types Requires
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and After to all units that
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have been configured for
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stdout or stderr to be
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connected to syslog or the
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kernel log buffer.</p></dd><dt><span class="term"><code class="filename">systemd-shutdownd.service</code></span></dt><dd><p>This is internally used
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<span class="citerefentry"><span class="refentrytitle">shutdown</span>(8)</span>
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to implement delayed shutdowns.</p><p>This is a
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socket-activated service, see
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<code class="filename">system-shutdownd.socket</code>.</p></dd><dt><span class="term"><code class="filename">systemd-shutdownd.socket</code></span></dt><dd><p>Socket activation unit
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<code class="filename">system-shutdownd.service</code>.</p></dd><dt><span class="term"><code class="filename">time-sync.target</code></span></dt><dd><p>systemd automatically
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adds dependencies of type
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After for this target unit to
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all SysV init script service
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units with an LSB header
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<code class="literal">$time</code>
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facility.</p></dd><dt><span class="term"><code class="filename">umount.target</code></span></dt><dd><p>A special target unit
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that umounts all mount and
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automount points on system
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shutdown.</p><p>Mounts that shall be
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unmounted on system shutdown
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dependencies to this unit for
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their mount unit, which is
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<code class="varname">DefaultDependencies=yes</code>
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is set (the default).</p></dd></dl></div></div><div class="refsect1" title="Special User Units"><a id="id319313"/><h2>Special User Units</h2><p>When systemd runs as a user instance, the
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following special units are available, which have
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similar definitions as their system counterparts:
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<code class="filename">default.target</code>,
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<code class="filename">local-fs.target</code>,
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<code class="filename">remote-fs.target</code>,
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<code class="filename">shutdown.target</code>,
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<code class="filename">sockets.target</code>,
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<code class="filename">swap.target</code>.</p><p>In addition the following special unit is
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understood only when systemd runs as service instance:</p><div class="variablelist"><dl><dt><span class="term"><code class="filename">exit.service</code></span></dt><dd><p>A special service unit
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for shutting down the
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user service manager.</p><p>Applications wanting to
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terminate the user service
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manager should start this
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unit. If systemd receives
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SIGTERM or SIGINT when running
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as user service daemon it will
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start this unit.</p><p>Normally, this pulls in
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<code class="filename">shutdown.target</code>
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which in turn should be
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conflicted by all units that
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want to be shut down on
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user service manager exit.</p></dd></dl></div></div><div class="refsect1" title="See Also"><a id="id319398"/><h2>See Also</h2><p>
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<span class="citerefentry"><span class="refentrytitle">systemd.unit</span>(5)</span>,
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<span class="citerefentry"><span class="refentrytitle">systemd.service</span>(5)</span>,
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<span class="citerefentry"><span class="refentrytitle">systemd.socket</span>(5)</span>,
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<span class="citerefentry"><span class="refentrytitle">systemd.target</span>(5)</span>
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