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.\" Title: systemd.special
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.\" Author: Lennart Poettering <lennart@poettering.net>
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.\" Generator: DocBook XSL Stylesheets v1.76.1 <http://docbook.sf.net/>
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.\" Manual: systemd.special
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.TH "SYSTEMD\&.SPECIAL" "7" "03/16/2012" "systemd" "systemd.special"
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.\" * Define some portability stuff
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.\" http://bugs.debian.org/507673
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.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
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.\" * MAIN CONTENT STARTS HERE *
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systemd.special \- special systemd units
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ctrl\-alt\-del\&.target,
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display\-manager\&.service,
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local\-fs\-pre\&.target,
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mail\-transfer\-agent\&.target,
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remote\-fs\-pre\&.target,
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systemd\-initctl\&.service,
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systemd\-initctl\&.socket,
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systemd\-stdout\-syslog\-bridge\&.service,
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systemd\-stdout\-syslog\-bridge\&.socket,
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A few units are treated specially by systemd\&. They have special internal semantics and cannot be renamed\&.
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.SH "SPECIAL SYSTEM UNITS"
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A special target unit covering early boot\-up\&.
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systemd automatically adds dependencies of the types Requires and After for this target unit to all SysV service units configured for runlevel 1 to 5\&.
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Usually this should pull\-in all sockets, mount points, swap devices and other basic initialization necessary for the general purpose daemons\&. Most normal daemons should have dependencies of type After and Requires on this unit\&.
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ctrl\-alt\-del\&.target
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systemd starts this target whenever Control+Alt+Del is pressed on the console\&. Usually this should be aliased (symlinked) to
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A special unit for the D\-Bus system bus\&. As soon as this service is fully started up systemd will connect to it and register its service\&.
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The default unit systemd starts at bootup\&. Usually this should be aliased (symlinked) to
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graphical\&.target\&.
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The default unit systemd starts at bootup can be overridden with the
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\fIsystemd\&.unit=\fR
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kernel command line option\&.
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display\-manager\&.service
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The display manager service\&. Usually this should be aliased (symlinked) to
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or a similar display manager service\&.
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systemd automatically adds dependencies of type After for this target unit to all SysV init script service units with a LSB header referring to the
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facility, for compatibility with Debian\&.
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A special target unit that starts an emergency shell on the main console\&. This unit is supposed to be used with the kernel command line option
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\fIsystemd\&.unit=\fR
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and has otherwise little use\&.
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A special target unit for setting up a graphical login screen\&. This pulls in
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multi\-user\&.target\&.
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Units that are needed for graphical login shall add Wants dependencies for their unit to this unit (or
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multi\-user\&.target) during installation\&.
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A special target unit for shutting down and halting the system\&.
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Applications wanting to halt the system should start this unit\&.
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systemd starts this target whenever Alt+ArrowUp is pressed on the console\&. This is a good candidate to be aliased (symlinked) to
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systemd automatically adds dependencies of type After to all mount units that refer to local mount points for this target unit\&. In addition, systemd adds dependencies of type Wants to this target unit for those mounts listed in
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\fBcomment=systemd\&.mount\fR
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systemd automatically adds dependencies of type After for this target unit to all SysV init script service units with an LSB header referring to the
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local\-fs\-pre\&.target
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This target unit is automatically ordered before all local mount points marked with
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(see above)\&. It can be used to execute certain units before all local mounts\&.
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mail\-transfer\-agent\&.target
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The mail transfer agent (MTA) service\&. Usually this should pull\-in all units necessary for sending/receiving mails on the local host\&.
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systemd automatically adds dependencies of type After for this target unit to all SysV init script service units with an LSB header referring to the
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$mail\-transfer\-agent
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$mail\-transport\-agent
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facilities, for compatibility with Debian\&.
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A special target unit for setting up a multi\-user system (non\-graphical)\&. This is pulled in by
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graphical\&.target\&.
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Units that are needed for a multi\-user system shall add Wants dependencies to this unit for their unit during installation\&.
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systemd automatically adds dependencies of type After for this target unit to all SysV init script service units with an LSB header referring to the
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systemd automatically adds dependencies of type After for this target unit to all SysV init script service units with an LSB header referring to the
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A special target unit for shutting down and powering off the system\&.
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Applications wanting to power off the system should start this unit\&.
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is an alias for this target unit, for compatibility with SysV\&.
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A special target unit for shutting down and rebooting the system\&.
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Applications wanting to reboot the system should start this unit\&.
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is an alias for this target unit, for compatibility with SysV\&.
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local\-fs\&.target, but for remote mount points\&.
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systemd automatically adds dependencies of type After for this target unit to all SysV init script service units with an LSB header referring to the
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remote\-fs\-pre\&.target
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This target unit is automatically ordered before all remote mount points marked with
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(see above)\&. It can be used to execute certain units before all remote mounts\&.
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A special target unit for setting up the base system and a rescue shell\&.
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is an alias for this target unit, for compatibility with SysV\&.
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systemd automatically adds dependencies of type After for this target unit to all SysV init script service units with an LSB header referring to the
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This is a target that is called whenever the SysV compatibility code asks for runlevel 2\&. It is a good idea to make this an alias for (i\&.e\&. symlink to)
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multi\-user\&.target\&.
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This is a target that is called whenever the SysV compatibility code asks for runlevel 3\&. It is a good idea to make this an alias for (i\&.e\&. symlink to)
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graphical\&.target\&.
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This is a target that is called whenever the SysV compatibility code asks for runlevel 4\&. It is a good idea to make this an alias for (i\&.e\&. symlink to)
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graphical\&.target\&.
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This is a target that is called whenever the SysV compatibility code asks for runlevel 5\&. It is a good idea to make this an alias for (i\&.e\&. symlink to)
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graphical\&.target\&.
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A special target unit that terminates the services on system shutdown\&.
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Services that shall be terminated on system shutdown shall add Conflicts dependencies to this unit for their service unit, which is implicitly done when
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\fIDefaultDependencies=yes\fR
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is set (the default)\&.
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systemd automatically adds dependencies of type Conflicts to this target unit for all SysV init script service units that shall be terminated in SysV runlevels 0 or 6\&.
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A special target that is started when systemd receives the SIGPWR process signal, which is normally sent by the kernel or UPS daemons when power fails\&.
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A special target unit that sets up all service sockets\&.
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Services that can be socket\-activated shall add Wants dependencies to this unit for their socket unit during installation\&.
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local\-fs\&.target, but for swap partitions and swap files\&.
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A special target unit covering early boot\-up scripts\&.
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systemd automatically adds dependencies of the types Wants and After for all SysV service units configured for runlevels that are not 0 to 6 to this target unit\&. This covers the special boot\-up runlevels some distributions have, such as S or b\&.
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systemd automatically adds dependencies of type After for this target unit to all SysV init script service units with an LSB header referring to the
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systemd\-initctl\&.service
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This provides compatibility with the SysV /dev/initctl file system FIFO for communication with the init system\&.
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This is a socket\-activated service, see
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system\-initctl\&.socket\&.
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systemd\-initctl\&.socket
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Socket activation unit for
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system\-initctl\&.service\&.
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systemd\-stdout\-syslog\-bridge\&.service
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This is internally used by systemd to provide syslog logging to the processes it maintains\&.
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This is a socket\-activated service, see
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system\-stdout\-syslog\-bridge\&.socket\&.
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systemd\-stdout\-syslog\-bridge\&.socket
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Socket activation unit for
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system\-stdout\-syslog\-bridge\&.service\&. systemd will automatically add dependencies of types Requires and After to all units that have been configured for stdout or stderr to be connected to syslog or the kernel log buffer\&.
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systemd\-shutdownd\&.service
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This is internally used by
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to implement delayed shutdowns\&.
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This is a socket\-activated service, see
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system\-shutdownd\&.socket\&.
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systemd\-shutdownd\&.socket
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Socket activation unit for
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system\-shutdownd\&.service\&.
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systemd automatically adds dependencies of type After for this target unit to all SysV init script service units with an LSB header referring to the
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A special target unit that umounts all mount and automount points on system shutdown\&.
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Mounts that shall be unmounted on system shutdown shall add Conflicts dependencies to this unit for their mount unit, which is implicitly done when
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\fIDefaultDependencies=yes\fR
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is set (the default)\&.
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.SH "SPECIAL USER UNITS"
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When systemd runs as a user instance, the following special units are available, which have similar definitions as their system counterparts:
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In addition the following special unit is understood only when systemd runs as service instance:
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A special service unit for shutting down the user service manager\&.
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Applications wanting to terminate the user service manager should start this unit\&. If systemd receives SIGTERM or SIGINT when running as user service daemon it will start this unit\&.
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Normally, this pulls in
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which in turn should be conflicted by all units that want to be shut down on user service manager exit\&.
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\fBsystemd.unit\fR(5),
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\fBsystemd.service\fR(5),
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\fBsystemd.socket\fR(5),
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\fBsystemd.target\fR(5)
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\fBLennart Poettering\fR <\&lennart@poettering\&.net\&>
added
removed
man/systemd.special.7
