man/init.html

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  22   <a href="../libudev/index.html">gudev </a><span style="float:right">systemd 219</span><hr><div class="refentry"><a name="systemd"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>systemd, init — systemd system and service manager</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="cmdsynopsis"><p><code class="command">systemd [OPTIONS...]</code> </p></div><div class="cmdsynopsis"><p><code class="command">init [OPTIONS...]  {COMMAND}</code> </p></div></div><div class="refsect1"><a name="idm139844740524032"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description">¶</a></h2><p>systemd is a system and service manager for Linux operating
  23     systems. When run as first process on boot (as PID 1), it acts as
  24     init system that brings up and maintains userspace
  25     services.</p><p>For compatibility with SysV, if systemd is called as
  26     <span class="command"><strong>init</strong></span> and a PID that is not 1, it will execute
  27     <span class="command"><strong>telinit</strong></span> and pass all command line arguments
  28     unmodified. That means <span class="command"><strong>init</strong></span> and
  29     <span class="command"><strong>telinit</strong></span> are mostly equivalent when invoked from
  30     normal login sessions. See
  31     <a href="telinit.html"><span class="citerefentry"><span class="refentrytitle">telinit</span>(8)</span></a>
  32     for more information.</p><p>When run as a system instance, systemd interprets the
  33     configuration file <code class="filename">system.conf</code> and the files
  34     in <code class="filename">system.conf.d</code> directories; when run as a
  35     user instance, systemd interprets the configuration file
  36     <code class="filename">user.conf</code> and the files in
  37     <code class="filename">user.conf.d</code> directories. See
  38     <a href="systemd-system.conf.html"><span class="citerefentry"><span class="refentrytitle">systemd-system.conf</span>(5)</span></a>
  39     for more information.</p></div><div class="refsect1"><a name="idm139844740514384"></a><h2 id="Options">Options<a class="headerlink" title="Permalink to this headline" href="#Options">¶</a></h2><p>The following options are understood:</p><div class="variablelist"><dl class="variablelist"><dt id="--test"><span class="term"><code class="option">--test</code></span><a class="headerlink" title="Permalink to this term" href="#--test">¶</a></dt><dd><p>Determine startup sequence, dump it and exit.
  40         This is an option useful for debugging only.</p></dd><dt id="--dump-configuration-items"><span class="term"><code class="option">--dump-configuration-items</code></span><a class="headerlink" title="Permalink to this term" href="#--dump-configuration-items">¶</a></dt><dd><p>Dump understood unit configuration items. This
  41         outputs a terse but complete list of configuration items
  42         understood in unit definition files.</p></dd><dt id="--unit="><span class="term"><code class="option">--unit=</code></span><a class="headerlink" title="Permalink to this term" href="#--unit=">¶</a></dt><dd><p>Set default unit to activate on startup. If
  43         not specified, defaults to
  44         <code class="filename">default.target</code>.</p></dd><dt id="--system"><span class="term"><code class="option">--system</code>, </span><span class="term"><code class="option">--user</code></span><a class="headerlink" title="Permalink to this term" href="#--system">¶</a></dt><dd><p>For <code class="option">--system</code>, tell systemd to
  45         run a system instance, even if the process ID is not 1, i.e.
  46         systemd is not run as init process. <code class="option">--user</code>
  47         does the opposite, running a user instance even if the process
  48         ID is 1. Normally it should not be necessary to pass these
  49         options, as systemd automatically detects the mode it is
  50         started in. These options are hence of little use except for
  51         debugging. Note that it is not supported booting and
  52         maintaining a full system with systemd running in
  53         <code class="option">--system</code> mode, but PID not 1. In practice,
  54         passing <code class="option">--system</code> explicitly is only useful in
  55         conjunction with <code class="option">--test</code>.</p></dd><dt id="--dump-core"><span class="term"><code class="option">--dump-core</code></span><a class="headerlink" title="Permalink to this term" href="#--dump-core">¶</a></dt><dd><p>Dump core on crash. This switch has no effect
  56         when run as user instance.</p></dd><dt id="--crash-shell"><span class="term"><code class="option">--crash-shell</code></span><a class="headerlink" title="Permalink to this term" href="#--crash-shell">¶</a></dt><dd><p>Run shell on
  57         crash. This switch has no effect when
  58         run as user
  59         instance.</p></dd><dt id="--confirm-spawn"><span class="term"><code class="option">--confirm-spawn</code></span><a class="headerlink" title="Permalink to this term" href="#--confirm-spawn">¶</a></dt><dd><p>Ask for confirmation when spawning processes.
  60         This switch has no effect when run as user
  61         instance.</p></dd><dt id="--show-status="><span class="term"><code class="option">--show-status=</code></span><a class="headerlink" title="Permalink to this term" href="#--show-status=">¶</a></dt><dd><p>Show terse service status information while
  62         booting. This switch has no effect when run as user instance.
  63         Takes a boolean argument which may be omitted which is
  64         interpreted as <code class="option">true</code>.</p></dd><dt id="--log-target="><span class="term"><code class="option">--log-target=</code></span><a class="headerlink" title="Permalink to this term" href="#--log-target=">¶</a></dt><dd><p>Set log target. Argument must be one of
  65         <code class="option">console</code>,
  66         <code class="option">journal</code>,
  67         <code class="option">kmsg</code>,
  68         <code class="option">journal-or-kmsg</code>,
  69         <code class="option">null</code>.</p></dd><dt id="--log-level="><span class="term"><code class="option">--log-level=</code></span><a class="headerlink" title="Permalink to this term" href="#--log-level=">¶</a></dt><dd><p>Set log level. As
  70         argument this accepts a numerical log
  71         level or the well-known <a href="http://man7.org/linux/man-pages/man3/syslog.3.html"><span class="citerefentry"><span class="refentrytitle">syslog</span>(3)</span></a>
  72         symbolic names (lowercase):
  73         <code class="option">emerg</code>,
  74         <code class="option">alert</code>,
  75         <code class="option">crit</code>,
  76         <code class="option">err</code>,
  77         <code class="option">warning</code>,
  78         <code class="option">notice</code>,
  79         <code class="option">info</code>,
  80         <code class="option">debug</code>.</p></dd><dt id="--log-color="><span class="term"><code class="option">--log-color=</code></span><a class="headerlink" title="Permalink to this term" href="#--log-color=">¶</a></dt><dd><p>Highlight important log messages. Argument is
  81         a boolean value. If the argument is omitted, it defaults to
  82         <code class="option">true</code>.</p></dd><dt id="--log-location="><span class="term"><code class="option">--log-location=</code></span><a class="headerlink" title="Permalink to this term" href="#--log-location=">¶</a></dt><dd><p>Include code location in log messages. This is
  83         mostly relevant for debugging purposes. Argument is a boolean
  84         value. If the argument is omitted it defaults to
  85         <code class="option">true</code>.</p></dd><dt id="--default-standard-output="><span class="term"><code class="option">--default-standard-output=</code>, </span><span class="term"><code class="option">--default-standard-error=</code></span><a class="headerlink" title="Permalink to this term" href="#--default-standard-output=">¶</a></dt><dd><p>Sets the default output or error output for
  86         all services and sockets, respectively. That is, controls the
  87         default for <code class="option">StandardOutput=</code> and
  88         <code class="option">StandardError=</code> (see
  89         <a href="systemd.exec.html"><span class="citerefentry"><span class="refentrytitle">systemd.exec</span>(5)</span></a>
  90         for details). Takes one of
  91         <code class="option">inherit</code>,
  92         <code class="option">null</code>,
  93         <code class="option">tty</code>,
  94         <code class="option">journal</code>,
  95         <code class="option">journal+console</code>,
  96         <code class="option">syslog</code>,
  97         <code class="option">syslog+console</code>,
  98         <code class="option">kmsg</code>,
  99         <code class="option">kmsg+console</code>.  If the
 100         argument is omitted
 101         <code class="option">--default-standard-output=</code> defaults to
 102         <code class="option">journal</code> and
 103         <code class="option">--default-standard-error=</code> to
 104         <code class="option">inherit</code>.</p></dd><dt id="-h"><span class="term"><code class="option">-h</code>, </span><span class="term"><code class="option">--help</code></span><a class="headerlink" title="Permalink to this term" href="#-h">¶</a></dt><dd><p><a name="help-text"></a>Print a short help text and exit.
 105     </p></dd><dt id="--version"><span class="term"><code class="option">--version</code></span><a class="headerlink" title="Permalink to this term" href="#--version">¶</a></dt><dd><p><a name="version-text"></a>Print a short version string and exit.</p></dd></dl></div></div><div class="refsect1"><a name="idm139844744180768"></a><h2 id="Concepts">Concepts<a class="headerlink" title="Permalink to this headline" href="#Concepts">¶</a></h2><p>systemd provides a dependency system between various
 106     entities called "units" of 12 different types. Units encapsulate
 107     various objects that are relevant for system boot-up and
 108     maintenance. The majority of units are configured in unit
 109     configuration files, whose syntax and basic set of options is
 110     described in
 111     <a href="systemd.unit.html"><span class="citerefentry"><span class="refentrytitle">systemd.unit</span>(5)</span></a>,
 112     however some are created automatically from other configuration,
 113     dynamically from system state or programmatically at runtime.
 114     Units may be "active" (meaning started, bound, plugged in, ...,
 115     depending on the unit type, see below), or "inactive" (meaning
 116     stopped, unbound, unplugged, ...), as well as in the process of
 117     being activated or deactivated, i.e. between the two states (these
 118     states are called "activating", "deactivating"). A special
 119     "failed" state is available as well, which is very similar to
 120     "inactive" and is entered when the service failed in some way
 121     (process returned error code on exit, or crashed, or an operation
 122     timed out). If this state is entered, the cause will be logged,
 123     for later reference. Note that the various unit types may have a
 124     number of additional substates, which are mapped to the five
 125     generalized unit states described here.</p><p>The following unit types are available:</p><div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><p>Service units, which start and control daemons
 126       and the processes they consist of. For details see
 127       <a href="systemd.service.html"><span class="citerefentry"><span class="refentrytitle">systemd.service</span>(5)</span></a>.</p></li><li class="listitem"><p>Socket units, which encapsulate local IPC or
 128       network sockets in the system, useful for socket-based
 129       activation. For details about socket units see
 130       <a href="systemd.socket.html"><span class="citerefentry"><span class="refentrytitle">systemd.socket</span>(5)</span></a>,
 131       for details on socket-based activation and other forms of
 132       activation, see
 133       <a href="daemon.html"><span class="citerefentry"><span class="refentrytitle">daemon</span>(7)</span></a>.</p></li><li class="listitem"><p>Target units are useful to group units, or
 134       provide well-known synchronization points during boot-up, see
 135       <a href="systemd.target.html"><span class="citerefentry"><span class="refentrytitle">systemd.target</span>(5)</span></a>.</p></li><li class="listitem"><p>Device units expose kernel devices in systemd
 136       and may be used to implement device-based activation. For
 137       details see
 138       <a href="systemd.device.html"><span class="citerefentry"><span class="refentrytitle">systemd.device</span>(5)</span></a>.</p></li><li class="listitem"><p>Mount units control mount points in the file
 139       system, for details see
 140       <a href="systemd.mount.html"><span class="citerefentry"><span class="refentrytitle">systemd.mount</span>(5)</span></a>.</p></li><li class="listitem"><p>Automount units provide automount capabilities,
 141       for on-demand mounting of file systems as well as parallelized
 142       boot-up. See
 143       <a href="systemd.automount.html"><span class="citerefentry"><span class="refentrytitle">systemd.automount</span>(5)</span></a>.</p></li><li class="listitem"><p>Snapshot units can be used to temporarily save
 144       the state of the set of systemd units, which later may be
 145       restored by activating the saved snapshot unit. For more
 146       information see
 147       <a href="systemd.snapshot.html"><span class="citerefentry"><span class="refentrytitle">systemd.snapshot</span>(5)</span></a>.</p></li><li class="listitem"><p>Timer units are useful for triggering activation
 148       of other units based on timers. You may find details in
 149       <a href="systemd.timer.html"><span class="citerefentry"><span class="refentrytitle">systemd.timer</span>(5)</span></a>.</p></li><li class="listitem"><p>Swap units are very similar to mount units and
 150       encapsulate memory swap partitions or files of the operating
 151       system. They are described in
 152       <a href="systemd.swap.html"><span class="citerefentry"><span class="refentrytitle">systemd.swap</span>(5)</span></a>.</p></li><li class="listitem"><p>Path units may be used to activate other
 153       services when file system objects change or are modified. See
 154       <a href="systemd.path.html"><span class="citerefentry"><span class="refentrytitle">systemd.path</span>(5)</span></a>.</p></li><li class="listitem"><p>Slice units may be used to group units which
 155       manage system processes (such as service and scope units) in a
 156       hierarchical tree for resource management purposes. See
 157       <a href="systemd.slice.html"><span class="citerefentry"><span class="refentrytitle">systemd.slice</span>(5)</span></a>.</p></li><li class="listitem"><p>Scope units are similar to service units, but
 158       manage foreign processes instead of starting them as well. See
 159       <a href="systemd.scope.html"><span class="citerefentry"><span class="refentrytitle">systemd.scope</span>(5)</span></a>.</p></li></ol></div><p>Units are named as their configuration files. Some units
 160     have special semantics. A detailed list is available in
 161     <a href="systemd.special.html"><span class="citerefentry"><span class="refentrytitle">systemd.special</span>(7)</span></a>.</p><p>systemd knows various kinds of dependencies, including
 162     positive and negative requirement dependencies (i.e.
 163     <code class="varname">Requires=</code> and <code class="varname">Conflicts=</code>) as
 164     well as ordering dependencies (<code class="varname">After=</code> and
 165     <code class="varname">Before=</code>). NB: ordering and requirement
 166     dependencies are orthogonal. If only a requirement dependency
 167     exists between two units (e.g. <code class="filename">foo.service</code>
 168     requires <code class="filename">bar.service</code>), but no ordering
 169     dependency (e.g. <code class="filename">foo.service</code> after
 170     <code class="filename">bar.service</code>) and both are requested to start,
 171     they will be started in parallel. It is a common pattern that both
 172     requirement and ordering dependencies are placed between two
 173     units. Also note that the majority of dependencies are implicitly
 174     created and maintained by systemd. In most cases, it should be
 175     unnecessary to declare additional dependencies manually, however
 176     it is possible to do this.</p><p>Application programs and units (via dependencies) may
 177     request state changes of units. In systemd, these requests are
 178     encapsulated as 'jobs' and maintained in a job queue. Jobs may
 179     succeed or can fail, their execution is ordered based on the
 180     ordering dependencies of the units they have been scheduled
 181     for.</p><p>On boot systemd activates the target unit
 182     <code class="filename">default.target</code> whose job is to activate
 183     on-boot services and other on-boot units by pulling them in via
 184     dependencies. Usually the unit name is just an alias (symlink) for
 185     either <code class="filename">graphical.target</code> (for fully-featured
 186     boots into the UI) or <code class="filename">multi-user.target</code> (for
 187     limited console-only boots for use in embedded or server
 188     environments, or similar; a subset of graphical.target). However,
 189     it is at the discretion of the administrator to configure it as an
 190     alias to any other target unit. See
 191     <a href="systemd.special.html"><span class="citerefentry"><span class="refentrytitle">systemd.special</span>(7)</span></a>
 192     for details about these target units.</p><p>Processes systemd spawns are placed in individual Linux
 193     control groups named after the unit which they belong to in the
 194     private systemd hierarchy. (see <a class="ulink" href="https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt" target="_top">cgroups.txt</a>
 195     for more information about control groups, or short "cgroups").
 196     systemd uses this to effectively keep track of processes. Control
 197     group information is maintained in the kernel, and is accessible
 198     via the file system hierarchy (beneath
 199     <code class="filename">/sys/fs/cgroup/systemd/</code>), or in tools such as
 200     <a href="http://man7.org/linux/man-pages/man1/ps.1.html"><span class="citerefentry"><span class="refentrytitle">ps</span>(1)</span></a>
 201     (<span class="command"><strong>ps xawf -eo pid,user,cgroup,args</strong></span> is
 202     particularly useful to list all processes and the systemd units
 203     they belong to.).</p><p>systemd is compatible with the SysV init system to a large
 204     degree: SysV init scripts are supported and simply read as an
 205     alternative (though limited) configuration file format. The SysV
 206     <code class="filename">/dev/initctl</code> interface is provided, and
 207     compatibility implementations of the various SysV client tools are
 208     available. In addition to that, various established Unix
 209     functionality such as <code class="filename">/etc/fstab</code> or the
 210     <code class="filename">utmp</code> database are supported.</p><p>systemd has a minimal transaction system: if a unit is
 211     requested to start up or shut down it will add it and all its
 212     dependencies to a temporary transaction. Then, it will verify if
 213     the transaction is consistent (i.e. whether the ordering of all
 214     units is cycle-free). If it is not, systemd will try to fix it up,
 215     and removes non-essential jobs from the transaction that might
 216     remove the loop. Also, systemd tries to suppress non-essential
 217     jobs in the transaction that would stop a running service. Finally
 218     it is checked whether the jobs of the transaction contradict jobs
 219     that have already been queued, and optionally the transaction is
 220     aborted then. If all worked out and the transaction is consistent
 221     and minimized in its impact it is merged with all already
 222     outstanding jobs and added to the run queue. Effectively this
 223     means that before executing a requested operation, systemd will
 224     verify that it makes sense, fixing it if possible, and only
 225     failing if it really cannot work.</p><p>Systemd contains native implementations of various tasks
 226     that need to be executed as part of the boot process. For example,
 227     it sets the hostname or configures the loopback network device. It
 228     also sets up and mounts various API file systems, such as
 229     <code class="filename">/sys</code> or <code class="filename">/proc</code>.</p><p>For more information about the concepts and
 230     ideas behind systemd, please refer to the
 231     <a class="ulink" href="http://0pointer.de/blog/projects/systemd.html" target="_top">Original Design Document</a>.</p><p>Note that some but not all interfaces provided
 232     by systemd are covered by the
 233     <a class="ulink" href="http://www.freedesktop.org/wiki/Software/systemd/InterfaceStabilityPromise" target="_top">Interface
 234     Stability Promise</a>.</p><p>Units may be generated dynamically at boot and system
 235     manager reload time, for example based on other configuration
 236     files or parameters passed on the kernel command line. For details
 237     see the
 238     <a class="ulink" href="http://www.freedesktop.org/wiki/Software/systemd/Generators" target="_top">Generators Specification</a>.</p><p>Systems which invoke systemd in a container or initrd
 239     environment should implement the
 240     <a class="ulink" href="http://www.freedesktop.org/wiki/Software/systemd/ContainerInterface" target="_top">Container Interface</a> or
 241     <a class="ulink" href="http://www.freedesktop.org/wiki/Software/systemd/InitrdInterface" target="_top">initrd Interface</a>
 242     specifications, respectively.</p></div><div class="refsect1"><a name="idm139844739448288"></a><h2 id="Directories">Directories<a class="headerlink" title="Permalink to this headline" href="#Directories">¶</a></h2><div class="variablelist"><dl class="variablelist"><dt id="System unit directories"><span class="term">System unit directories</span><a class="headerlink" title="Permalink to this term" href="#System%20unit%20directories">¶</a></dt><dd><p>The systemd system manager reads unit
 243         configuration from various directories. Packages that want to
 244         install unit files shall place them in the directory returned
 245         by <span class="command"><strong>pkg-config systemd
 246         --variable=systemdsystemunitdir</strong></span>. Other directories
 247         checked are <code class="filename">/usr/local/lib/systemd/system</code>
 248         and <code class="filename">/usr/lib/systemd/system</code>. User
 249         configuration always takes precedence. <span class="command"><strong>pkg-config
 250         systemd --variable=systemdsystemconfdir</strong></span> returns the
 251         path of the system configuration directory. Packages should
 252         alter the content of these directories only with the
 253         <span class="command"><strong>enable</strong></span> and <span class="command"><strong>disable</strong></span>
 254         commands of the
 255         <a href="systemctl.html"><span class="citerefentry"><span class="refentrytitle">systemctl</span>(1)</span></a>
 256         tool. Full list of directories is provided in
 257         <a href="systemd.unit.html"><span class="citerefentry"><span class="refentrytitle">systemd.unit</span>(5)</span></a>.
 258         </p></dd></dl></div><div class="variablelist"><dl class="variablelist"><dt id="User unit directories"><span class="term">User unit directories</span><a class="headerlink" title="Permalink to this term" href="#User%20unit%20directories">¶</a></dt><dd><p>Similar rules apply for the user unit
 259         directories. However, here the
 260         <a class="ulink" href="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html" target="_top">XDG
 261         Base Directory specification</a> is followed to find
 262         units. Applications should place their unit files in the
 263         directory returned by <span class="command"><strong>pkg-config systemd
 264         --variable=systemduserunitdir</strong></span>. Global configuration
 265         is done in the directory reported by <span class="command"><strong>pkg-config
 266         systemd --variable=systemduserconfdir</strong></span>. The
 267         <span class="command"><strong>enable</strong></span> and <span class="command"><strong>disable</strong></span>
 268         commands of the
 269         <a href="systemctl.html"><span class="citerefentry"><span class="refentrytitle">systemctl</span>(1)</span></a>
 270         tool can handle both global (i.e. for all users) and private
 271         (for one user) enabling/disabling of units. Full list of
 272         directories is provided in
 273         <a href="systemd.unit.html"><span class="citerefentry"><span class="refentrytitle">systemd.unit</span>(5)</span></a>.
 274         </p></dd></dl></div><div class="variablelist"><dl class="variablelist"><dt id="SysV init scripts directory"><span class="term">SysV init scripts directory</span><a class="headerlink" title="Permalink to this term" href="#SysV%20init%20scripts%20directory">¶</a></dt><dd><p>The location of the SysV init script directory
 275         varies between distributions. If systemd cannot find a native
 276         unit file for a requested service, it will look for a SysV
 277         init script of the same name (with the
 278         <code class="filename">.service</code> suffix
 279         removed).</p></dd></dl></div><div class="variablelist"><dl class="variablelist"><dt id="SysV runlevel link farm directory"><span class="term">SysV runlevel link farm directory</span><a class="headerlink" title="Permalink to this term" href="#SysV%20runlevel%20link%20farm%20directory">¶</a></dt><dd><p>The location of the SysV runlevel link farm
 280         directory varies between distributions. systemd will take the
 281         link farm into account when figuring out whether a service
 282         shall be enabled. Note that a service unit with a native unit
 283         configuration file cannot be started by activating it in the
 284         SysV runlevel link farm.</p></dd></dl></div></div><div class="refsect1"><a name="idm139844739428496"></a><h2 id="Signals">Signals<a class="headerlink" title="Permalink to this headline" href="#Signals">¶</a></h2><div class="variablelist"><dl class="variablelist"><dt id="SIGTERM"><span class="term"><code class="constant">SIGTERM</code></span><a class="headerlink" title="Permalink to this term" href="#SIGTERM">¶</a></dt><dd><p>Upon receiving this signal the systemd system
 285         manager serializes its state, reexecutes itself and
 286         deserializes the saved state again. This is mostly equivalent
 287         to <span class="command"><strong>systemctl daemon-reexec</strong></span>.</p><p>systemd user managers will start the
 288         <code class="filename">exit.target</code> unit when this signal is
 289         received. This is mostly equivalent to <span class="command"><strong>systemctl
 290         --user start exit.target</strong></span>.</p></dd><dt id="SIGINT"><span class="term"><code class="constant">SIGINT</code></span><a class="headerlink" title="Permalink to this term" href="#SIGINT">¶</a></dt><dd><p>Upon receiving this signal the systemd system
 291         manager will start the
 292         <code class="filename">ctrl-alt-del.target</code> unit. This is mostly
 293         equivalent to <span class="command"><strong>systemctl start
 294         ctl-alt-del.target</strong></span>. If this signal is received more
 295         often than 7 times per 2s an immediate reboot is triggered.
 296         Note that pressing Ctrl-Alt-Del on the console will trigger
 297         this signal. Hence, if a reboot is hanging pressing
 298         Ctrl-Alt-Del more than 7 times in 2s is a relatively safe way
 299         to trigger an immediate reboot.</p><p>systemd user managers treat this signal the same way as
 300         <code class="constant">SIGTERM</code>.</p></dd><dt id="SIGWINCH"><span class="term"><code class="constant">SIGWINCH</code></span><a class="headerlink" title="Permalink to this term" href="#SIGWINCH">¶</a></dt><dd><p>When this signal is received the systemd
 301         system manager will start the
 302         <code class="filename">kbrequest.target</code> unit. This is mostly
 303         equivalent to <span class="command"><strong>systemctl start
 304         kbrequest.target</strong></span>.</p><p>This signal is ignored by systemd user
 305         managers.</p></dd><dt id="SIGPWR"><span class="term"><code class="constant">SIGPWR</code></span><a class="headerlink" title="Permalink to this term" href="#SIGPWR">¶</a></dt><dd><p>When this signal is received the systemd
 306         manager will start the <code class="filename">sigpwr.target</code>
 307         unit. This is mostly equivalent to <span class="command"><strong>systemctl start
 308         sigpwr.target</strong></span>.</p></dd><dt id="SIGUSR1"><span class="term"><code class="constant">SIGUSR1</code></span><a class="headerlink" title="Permalink to this term" href="#SIGUSR1">¶</a></dt><dd><p>When this signal is received the systemd
 309         manager will try to reconnect to the D-Bus
 310         bus.</p></dd><dt id="SIGUSR2"><span class="term"><code class="constant">SIGUSR2</code></span><a class="headerlink" title="Permalink to this term" href="#SIGUSR2">¶</a></dt><dd><p>When this signal is received the systemd
 311         manager will log its complete state in human readable form.
 312         The data logged is the same as printed by
 313         <span class="command"><strong>systemd-analyze dump</strong></span>.</p></dd><dt id="SIGHUP"><span class="term"><code class="constant">SIGHUP</code></span><a class="headerlink" title="Permalink to this term" href="#SIGHUP">¶</a></dt><dd><p>Reloads the complete daemon configuration.
 314         This is mostly equivalent to <span class="command"><strong>systemctl
 315         daemon-reload</strong></span>.</p></dd><dt id="SIGRTMIN+0"><span class="term"><code class="constant">SIGRTMIN+0</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+0">¶</a></dt><dd><p>Enters default mode, starts the
 316         <code class="filename">default.target</code> unit. This is mostly
 317         equivalent to <span class="command"><strong>systemctl start
 318         default.target</strong></span>.</p></dd><dt id="SIGRTMIN+1"><span class="term"><code class="constant">SIGRTMIN+1</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+1">¶</a></dt><dd><p>Enters rescue mode, starts the
 319         <code class="filename">rescue.target</code> unit. This is mostly
 320         equivalent to <span class="command"><strong>systemctl isolate
 321         rescue.target</strong></span>.</p></dd><dt id="SIGRTMIN+2"><span class="term"><code class="constant">SIGRTMIN+2</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+2">¶</a></dt><dd><p>Enters emergency mode, starts the
 322         <code class="filename">emergency.service</code> unit. This is mostly
 323         equivalent to <span class="command"><strong>systemctl isolate
 324         emergency.service</strong></span>.</p></dd><dt id="SIGRTMIN+3"><span class="term"><code class="constant">SIGRTMIN+3</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+3">¶</a></dt><dd><p>Halts the machine, starts the
 325         <code class="filename">halt.target</code> unit. This is mostly
 326         equivalent to <span class="command"><strong>systemctl start
 327         halt.target</strong></span>.</p></dd><dt id="SIGRTMIN+4"><span class="term"><code class="constant">SIGRTMIN+4</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+4">¶</a></dt><dd><p>Powers off the machine, starts the
 328         <code class="filename">poweroff.target</code> unit. This is mostly
 329         equivalent to <span class="command"><strong>systemctl start
 330         poweroff.target</strong></span>.</p></dd><dt id="SIGRTMIN+5"><span class="term"><code class="constant">SIGRTMIN+5</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+5">¶</a></dt><dd><p>Reboots the machine, starts the
 331         <code class="filename">reboot.target</code> unit. This is mostly
 332         equivalent to <span class="command"><strong>systemctl start
 333         reboot.target</strong></span>.</p></dd><dt id="SIGRTMIN+6"><span class="term"><code class="constant">SIGRTMIN+6</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+6">¶</a></dt><dd><p>Reboots the machine via kexec, starts the
 334         <code class="filename">kexec.target</code> unit. This is mostly
 335         equivalent to <span class="command"><strong>systemctl start
 336         kexec.target</strong></span>.</p></dd><dt id="SIGRTMIN+13"><span class="term"><code class="constant">SIGRTMIN+13</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+13">¶</a></dt><dd><p>Immediately halts the machine.</p></dd><dt id="SIGRTMIN+14"><span class="term"><code class="constant">SIGRTMIN+14</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+14">¶</a></dt><dd><p>Immediately powers off the machine.</p></dd><dt id="SIGRTMIN+15"><span class="term"><code class="constant">SIGRTMIN+15</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+15">¶</a></dt><dd><p>Immediately reboots the machine.</p></dd><dt id="SIGRTMIN+16"><span class="term"><code class="constant">SIGRTMIN+16</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+16">¶</a></dt><dd><p>Immediately reboots the machine with kexec.</p></dd><dt id="SIGRTMIN+20"><span class="term"><code class="constant">SIGRTMIN+20</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+20">¶</a></dt><dd><p>Enables display of status messages on the
 337         console, as controlled via
 338         <code class="varname">systemd.show_status=1</code> on the kernel command
 339         line.</p></dd><dt id="SIGRTMIN+21"><span class="term"><code class="constant">SIGRTMIN+21</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+21">¶</a></dt><dd><p>Disables display of
 340         status messages on the console, as
 341         controlled via
 342         <code class="varname">systemd.show_status=0</code>
 343         on the kernel command
 344         line.</p></dd><dt id="SIGRTMIN+22"><span class="term"><code class="constant">SIGRTMIN+22</code>, </span><span class="term"><code class="constant">SIGRTMIN+23</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+22">¶</a></dt><dd><p>Sets the log level to "<code class="literal">debug</code>"
 345         (or "<code class="literal">info</code>" on
 346         <code class="constant">SIGRTMIN+23</code>), as controlled via
 347         <code class="varname">systemd.log_level=debug</code> (or
 348         <code class="varname">systemd.log_level=info</code> on
 349         <code class="constant">SIGRTMIN+23</code>) on the kernel command
 350         line.</p></dd><dt id="SIGRTMIN+24"><span class="term"><code class="constant">SIGRTMIN+24</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+24">¶</a></dt><dd><p>Immediately exits the manager (only available
 351         for --user instances).</p></dd><dt id="SIGRTMIN+26"><span class="term"><code class="constant">SIGRTMIN+26</code>, </span><span class="term"><code class="constant">SIGRTMIN+27</code>, </span><span class="term"><code class="constant">SIGRTMIN+28</code></span><a class="headerlink" title="Permalink to this term" href="#SIGRTMIN+26">¶</a></dt><dd><p>Sets the log level to
 352         "<code class="literal">journal-or-kmsg</code>" (or
 353         "<code class="literal">console</code>" on
 354         <code class="constant">SIGRTMIN+27</code>, "<code class="literal">kmsg</code>" on
 355         <code class="constant">SIGRTMIN+28</code>), as controlled via
 356         <code class="varname">systemd.log_target=journal-or-kmsg</code> (or
 357         <code class="varname">systemd.log_target=console</code> on
 358         <code class="constant">SIGRTMIN+27</code> or
 359         <code class="varname">systemd.log_target=kmsg</code> on
 360         <code class="constant">SIGRTMIN+28</code>) on the kernel command
 361         line.</p></dd></dl></div></div><div class="refsect1"><a name="idm139844739366368"></a><h2 id="Environment">Environment<a class="headerlink" title="Permalink to this headline" href="#Environment">¶</a></h2><div class="variablelist"><dl class="variablelist"><dt id="$SYSTEMD_LOG_LEVEL"><span class="term"><code class="varname">$SYSTEMD_LOG_LEVEL</code></span><a class="headerlink" title="Permalink to this term" href="#%24SYSTEMD_LOG_LEVEL">¶</a></dt><dd><p>systemd reads the log level from this
 362         environment variable. This can be overridden with
 363         <code class="option">--log-level=</code>.</p></dd><dt id="$SYSTEMD_LOG_TARGET"><span class="term"><code class="varname">$SYSTEMD_LOG_TARGET</code></span><a class="headerlink" title="Permalink to this term" href="#%24SYSTEMD_LOG_TARGET">¶</a></dt><dd><p>systemd reads the log target from this
 364         environment variable. This can be overridden with
 365         <code class="option">--log-target=</code>.</p></dd><dt id="$SYSTEMD_LOG_COLOR"><span class="term"><code class="varname">$SYSTEMD_LOG_COLOR</code></span><a class="headerlink" title="Permalink to this term" href="#%24SYSTEMD_LOG_COLOR">¶</a></dt><dd><p>Controls whether systemd highlights important
 366         log messages. This can be overridden with
 367         <code class="option">--log-color=</code>.</p></dd><dt id="$SYSTEMD_LOG_LOCATION"><span class="term"><code class="varname">$SYSTEMD_LOG_LOCATION</code></span><a class="headerlink" title="Permalink to this term" href="#%24SYSTEMD_LOG_LOCATION">¶</a></dt><dd><p>Controls whether systemd prints the code
 368         location along with log messages. This can be overridden with
 369         <code class="option">--log-location=</code>.</p></dd><dt id="$XDG_CONFIG_HOME"><span class="term"><code class="varname">$XDG_CONFIG_HOME</code>, </span><span class="term"><code class="varname">$XDG_CONFIG_DIRS</code>, </span><span class="term"><code class="varname">$XDG_DATA_HOME</code>, </span><span class="term"><code class="varname">$XDG_DATA_DIRS</code></span><a class="headerlink" title="Permalink to this term" href="#%24XDG_CONFIG_HOME">¶</a></dt><dd><p>The systemd user manager uses these variables
 370         in accordance to the <a class="ulink" href="http://standards.freedesktop.org/basedir-spec/basedir-spec-latest.html" target="_top">XDG
 371         Base Directory specification</a> to find its
 372         configuration.</p></dd><dt id="$SYSTEMD_UNIT_PATH"><span class="term"><code class="varname">$SYSTEMD_UNIT_PATH</code></span><a class="headerlink" title="Permalink to this term" href="#%24SYSTEMD_UNIT_PATH">¶</a></dt><dd><p>Controls where systemd looks for unit
 373         files.</p></dd><dt id="$SYSTEMD_SYSVINIT_PATH"><span class="term"><code class="varname">$SYSTEMD_SYSVINIT_PATH</code></span><a class="headerlink" title="Permalink to this term" href="#%24SYSTEMD_SYSVINIT_PATH">¶</a></dt><dd><p>Controls where systemd looks for SysV init
 374         scripts.</p></dd><dt id="$SYSTEMD_SYSVRCND_PATH"><span class="term"><code class="varname">$SYSTEMD_SYSVRCND_PATH</code></span><a class="headerlink" title="Permalink to this term" href="#%24SYSTEMD_SYSVRCND_PATH">¶</a></dt><dd><p>Controls where systemd looks for SysV init
 375         script runlevel link farms.</p></dd><dt id="$LISTEN_PID"><span class="term"><code class="varname">$LISTEN_PID</code>, </span><span class="term"><code class="varname">$LISTEN_FDS</code></span><a class="headerlink" title="Permalink to this term" href="#%24LISTEN_PID">¶</a></dt><dd><p>Set by systemd for supervised processes during
 376         socket-based activation. See
 377         <a href="sd_listen_fds.html"><span class="citerefentry"><span class="refentrytitle">sd_listen_fds</span>(3)</span></a>
 378         for more information. </p></dd><dt id="$NOTIFY_SOCKET"><span class="term"><code class="varname">$NOTIFY_SOCKET</code></span><a class="headerlink" title="Permalink to this term" href="#%24NOTIFY_SOCKET">¶</a></dt><dd><p>Set by systemd for supervised processes for
 379         status and start-up completion notification. See
 380         <a href="sd_notify.html"><span class="citerefentry"><span class="refentrytitle">sd_notify</span>(3)</span></a>
 381         for more information. </p></dd></dl></div></div><div class="refsect1"><a name="idm139844739344048"></a><h2 id="Kernel Command Line">Kernel Command Line<a class="headerlink" title="Permalink to this headline" href="#Kernel%20Command%20Line">¶</a></h2><p>When run as system instance systemd parses a number of
 382     kernel command line arguments<a href="#ftn.idm139844739343040" class="footnote" name="idm139844739343040"><sup class="footnote">[1]</sup></a>:</p><div class="variablelist"><dl class="variablelist"><dt id="systemd.unit="><span class="term"><code class="varname">systemd.unit=</code>, </span><span class="term"><code class="varname">rd.systemd.unit=</code></span><a class="headerlink" title="Permalink to this term" href="#systemd.unit=">¶</a></dt><dd><p>Overrides the unit to activate on boot.
 383         Defaults to <code class="filename">default.target</code>. This may be
 384         used to temporarily boot into a different boot unit, for
 385         example <code class="filename">rescue.target</code> or
 386         <code class="filename">emergency.service</code>. See
 387         <a href="systemd.special.html"><span class="citerefentry"><span class="refentrytitle">systemd.special</span>(7)</span></a>
 388         for details about these units. The option prefixed with
 389         "<code class="literal">rd.</code>" is honored only in the initial RAM disk
 390         (initrd), while the one that is not prefixed only in the main
 391         system.</p></dd><dt id="systemd.dump_core="><span class="term"><code class="varname">systemd.dump_core=</code></span><a class="headerlink" title="Permalink to this term" href="#systemd.dump_core=">¶</a></dt><dd><p>Takes a boolean argument. If
 392         <code class="option">true</code>, systemd dumps core when it crashes.
 393         Otherwise, no core dump is created. Defaults to
 394         <code class="option">true</code>.</p></dd><dt id="systemd.crash_shell="><span class="term"><code class="varname">systemd.crash_shell=</code></span><a class="headerlink" title="Permalink to this term" href="#systemd.crash_shell=">¶</a></dt><dd><p>Takes a boolean argument. If
 395         <code class="option">true</code>, systemd spawns a shell when it crashes.
 396         Otherwise, no shell is spawned. Defaults to
 397         <code class="option">false</code>, for security reasons, as the shell is
 398         not protected by any password
 399         authentication.</p></dd><dt id="systemd.crash_chvt="><span class="term"><code class="varname">systemd.crash_chvt=</code></span><a class="headerlink" title="Permalink to this term" href="#systemd.crash_chvt=">¶</a></dt><dd><p>Takes an integer argument. If positive systemd
 400         activates the specified virtual terminal when it crashes.
 401         Defaults to <code class="constant">-1</code>.</p></dd><dt id="systemd.confirm_spawn="><span class="term"><code class="varname">systemd.confirm_spawn=</code></span><a class="headerlink" title="Permalink to this term" href="#systemd.confirm_spawn=">¶</a></dt><dd><p>Takes a boolean argument. If
 402         <code class="option">true</code>, asks for confirmation when spawning
 403         processes. Defaults to
 404         <code class="option">false</code>.</p></dd><dt id="systemd.show_status="><span class="term"><code class="varname">systemd.show_status=</code></span><a class="headerlink" title="Permalink to this term" href="#systemd.show_status=">¶</a></dt><dd><p>Takes a boolean argument or the constant
 405         <code class="constant">auto</code>. If <code class="option">true</code>, shows
 406         terse service status updates on the console during bootup.
 407         <code class="constant">auto</code> behaves like <code class="option">false</code>
 408         until a service fails or there is a significant delay in boot.
 409         Defaults to <code class="option">true</code>, unless
 410         <code class="option">quiet</code> is passed as kernel command line option
 411         in which case it defaults to
 412         <code class="constant">auto</code>.</p></dd><dt id="systemd.log_target="><span class="term"><code class="varname">systemd.log_target=</code>, </span><span class="term"><code class="varname">systemd.log_level=</code>, </span><span class="term"><code class="varname">systemd.log_color=</code>, </span><span class="term"><code class="varname">systemd.log_location=</code></span><a class="headerlink" title="Permalink to this term" href="#systemd.log_target=">¶</a></dt><dd><p>Controls log output, with the same effect as
 413         the <code class="varname">$SYSTEMD_LOG_TARGET</code>,
 414         <code class="varname">$SYSTEMD_LOG_LEVEL</code>,
 415         <code class="varname">$SYSTEMD_LOG_COLOR</code>,
 416         <code class="varname">$SYSTEMD_LOG_LOCATION</code> environment variables
 417         described above.</p></dd><dt id="systemd.default_standard_output="><span class="term"><code class="varname">systemd.default_standard_output=</code>, </span><span class="term"><code class="varname">systemd.default_standard_error=</code></span><a class="headerlink" title="Permalink to this term" href="#systemd.default_standard_output=">¶</a></dt><dd><p>Controls default standard output and error
 418         output for services, with the same effect as the
 419         <code class="option">--default-standard-output=</code> and
 420         <code class="option">--default-standard-error=</code> command line
 421         arguments described above, respectively.</p></dd><dt id="systemd.setenv="><span class="term"><code class="varname">systemd.setenv=</code></span><a class="headerlink" title="Permalink to this term" href="#systemd.setenv=">¶</a></dt><dd><p>Takes a string argument in the form
 422         VARIABLE=VALUE. May be used to set default environment
 423         variables to add to forked child processes. May be used more
 424         than once to set multiple variables.</p></dd><dt id="quiet"><span class="term"><code class="varname">quiet</code></span><a class="headerlink" title="Permalink to this term" href="#quiet">¶</a></dt><dd><p>Turn off status output at boot, much like
 425         <code class="varname">systemd.show_status=false</code> would. Note that
 426         this option is also read by the kernel itself and disables
 427         kernel log output. Passing this option hence turns off the
 428         usual output from both the system manager and the kernel.
 429         </p></dd><dt id="debug"><span class="term"><code class="varname">debug</code></span><a class="headerlink" title="Permalink to this term" href="#debug">¶</a></dt><dd><p>Turn on debugging output. This is equivalent
 430         to <code class="varname">systemd.log_level=debug</code>. Note that this
 431         option is also read by the kernel itself and enables kernel
 432         debug output. Passing this option hence turns on the debug
 433         output from both the system manager and the
 434         kernel.</p></dd><dt id="emergency"><span class="term"><code class="varname">emergency</code>, </span><span class="term"><code class="varname">-b</code></span><a class="headerlink" title="Permalink to this term" href="#emergency">¶</a></dt><dd><p>Boot into emergency mode. This is equivalent
 435         to <code class="varname">systemd.unit=emergency.target</code> and
 436         provided for compatibility reasons and to be easier to
 437         type.</p></dd><dt id="rescue"><span class="term"><code class="varname">rescue</code>, </span><span class="term"><code class="varname">single</code>, </span><span class="term"><code class="varname">s</code>, </span><span class="term"><code class="varname">S</code>, </span><span class="term"><code class="varname">1</code></span><a class="headerlink" title="Permalink to this term" href="#rescue">¶</a></dt><dd><p>Boot into rescue mode. This is equivalent to
 438         <code class="varname">systemd.unit=rescue.target</code> and provided for
 439         compatibility reasons and to be easier to
 440         type.</p></dd><dt id="2"><span class="term"><code class="varname">2</code>, </span><span class="term"><code class="varname">3</code>, </span><span class="term"><code class="varname">4</code>, </span><span class="term"><code class="varname">5</code></span><a class="headerlink" title="Permalink to this term" href="#2">¶</a></dt><dd><p>Boot into the specified legacy SysV runlevel.
 441         These are equivalent to
 442         <code class="varname">systemd.unit=runlevel2.target</code>,
 443         <code class="varname">systemd.unit=runlevel3.target</code>,
 444         <code class="varname">systemd.unit=runlevel4.target</code>, and
 445         <code class="varname">systemd.unit=runlevel5.target</code>,
 446         respectively, and provided for compatibility reasons and to be
 447         easier to type.</p></dd><dt id="locale.LANG="><span class="term"><code class="varname">locale.LANG=</code>, </span><span class="term"><code class="varname">locale.LANGUAGE=</code>, </span><span class="term"><code class="varname">locale.LC_CTYPE=</code>, </span><span class="term"><code class="varname">locale.LC_NUMERIC=</code>, </span><span class="term"><code class="varname">locale.LC_TIME=</code>, </span><span class="term"><code class="varname">locale.LC_COLLATE=</code>, </span><span class="term"><code class="varname">locale.LC_MONETARY=</code>, </span><span class="term"><code class="varname">locale.LC_MESSAGES=</code>, </span><span class="term"><code class="varname">locale.LC_PAPER=</code>, </span><span class="term"><code class="varname">locale.LC_NAME=</code>, </span><span class="term"><code class="varname">locale.LC_ADDRESS=</code>, </span><span class="term"><code class="varname">locale.LC_TELEPHONE=</code>, </span><span class="term"><code class="varname">locale.LC_MEASUREMENT=</code>, </span><span class="term"><code class="varname">locale.LC_IDENTIFICATION=</code></span><a class="headerlink" title="Permalink to this term" href="#locale.LANG=">¶</a></dt><dd><p>Set the system locale to use. This overrides
 448         the settings in <code class="filename">/etc/locale.conf</code>. For
 449         more information see
 450         <a href="locale.conf.html"><span class="citerefentry"><span class="refentrytitle">locale.conf</span>(5)</span></a>
 451         and
 452         <a href="locale.html"><span class="citerefentry"><span class="refentrytitle">locale</span>(7)</span></a>.
 453         </p></dd></dl></div><p>For other kernel command line parameters understood by
 454     components of the core OS, please refer to
 455     <a href="kernel-command-line.html"><span class="citerefentry"><span class="refentrytitle">kernel-command-line</span>(7)</span></a>.</p></div><div class="refsect1"><a name="idm139844739285904"></a><h2 id="Sockets and FIFOs">Sockets and FIFOs<a class="headerlink" title="Permalink to this headline" href="#Sockets%20and%20FIFOs">¶</a></h2><div class="variablelist"><dl class="variablelist"><dt id="/run/systemd/notify"><span class="term"><code class="filename">/run/systemd/notify</code></span><a class="headerlink" title="Permalink to this term" href="#/run/systemd/notify">¶</a></dt><dd><p>Daemon status notification socket. This is an
 456         <code class="constant">AF_UNIX</code> datagram socket and is used to
 457         implement the daemon notification logic as implemented by
 458         <a href="sd_notify.html"><span class="citerefentry"><span class="refentrytitle">sd_notify</span>(3)</span></a>.</p></dd><dt id="/run/systemd/shutdownd"><span class="term"><code class="filename">/run/systemd/shutdownd</code></span><a class="headerlink" title="Permalink to this term" href="#/run/systemd/shutdownd">¶</a></dt><dd><p>Used internally by the
 459         <a href="shutdown.html"><span class="citerefentry"><span class="refentrytitle">shutdown</span>(8)</span></a>
 460         tool to implement delayed shutdowns. This is an
 461         <code class="constant">AF_UNIX</code> datagram
 462         socket.</p></dd><dt id="/run/systemd/private"><span class="term"><code class="filename">/run/systemd/private</code></span><a class="headerlink" title="Permalink to this term" href="#/run/systemd/private">¶</a></dt><dd><p>Used internally as communication channel
 463         between
 464         <a href="systemctl.html"><span class="citerefentry"><span class="refentrytitle">systemctl</span>(1)</span></a>
 465         and the systemd process. This is an
 466         <code class="constant">AF_UNIX</code> stream socket. This interface is
 467         private to systemd and should not be used in external
 468         projects.</p></dd><dt id="/dev/initctl"><span class="term"><code class="filename">/dev/initctl</code></span><a class="headerlink" title="Permalink to this term" href="#/dev/initctl">¶</a></dt><dd><p>Limited compatibility support for the SysV
 469         client interface, as implemented by the
 470         <code class="filename">systemd-initctl.service</code> unit. This is a
 471         named pipe in the file system. This interface is obsolete and
 472         should not be used in new applications.</p></dd></dl></div></div><div class="refsect1"><a name="idm139844739273408"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also">¶</a></h2><p>
 473       The <a class="ulink" href="http://www.freedesktop.org/wiki/Software/systemd/" target="_top">systemd Homepage</a>,
 474       <a href="systemd-system.conf.html"><span class="citerefentry"><span class="refentrytitle">systemd-system.conf</span>(5)</span></a>,
 475       <a href="locale.conf.html"><span class="citerefentry"><span class="refentrytitle">locale.conf</span>(5)</span></a>,
 476       <a href="systemctl.html"><span class="citerefentry"><span class="refentrytitle">systemctl</span>(1)</span></a>,
 477       <a href="journalctl.html"><span class="citerefentry"><span class="refentrytitle">journalctl</span>(1)</span></a>,
 478       <a href="systemd-notify.html"><span class="citerefentry"><span class="refentrytitle">systemd-notify</span>(1)</span></a>,
 479       <a href="daemon.html"><span class="citerefentry"><span class="refentrytitle">daemon</span>(7)</span></a>,
 480       <a href="sd-daemon.html"><span class="citerefentry"><span class="refentrytitle">sd-daemon</span>(3)</span></a>,
 481       <a href="systemd.unit.html"><span class="citerefentry"><span class="refentrytitle">systemd.unit</span>(5)</span></a>,
 482       <a href="systemd.special.html"><span class="citerefentry"><span class="refentrytitle">systemd.special</span>(5)</span></a>,
 483       <a href="http://linux.die.net/man/1/pkg-config"><span class="citerefentry"><span class="refentrytitle">pkg-config</span>(1)</span></a>,
 484       <a href="kernel-command-line.html"><span class="citerefentry"><span class="refentrytitle">kernel-command-line</span>(7)</span></a>,
 485       <a href="http://man7.org/linux/man-pages/man7/bootup.7.html"><span class="citerefentry"><span class="refentrytitle">bootup</span>(7)</span></a>,
 486       <a href="systemd.directives.html"><span class="citerefentry"><span class="refentrytitle">systemd.directives</span>(7)</span></a>
 487     </p></div><div class="footnotes"><br><hr style="width:100; text-align:left;margin-left: 0"><div id="ftn.idm139844739343040" class="footnote"><p><a href="#idm139844739343040" class="para"><sup class="para">[1] </sup></a>If run inside a Linux
 488     container these arguments may be passed as command line arguments
 489     to systemd itself, next to any of the command line options listed
 490     in the Options section above. If run outside of Linux containers,
 491     these arguments are parsed from <code class="filename">/proc/cmdline</code>
 492     instead.</p></div></div></div></body></html>