+ <refsect1>
+ <title>Kernel Command Line</title>
+
+ <para>When run as system instance systemd parses a
+ number of kernel command line
+ arguments<footnote><para>If run inside a Linux
+ container these arguments may be passed as command
+ line arguments to systemd itself, next to any of the
+ command line options listed in the Options section
+ above. If run outside of Linux containers, these
+ arguments are parsed from
+ <filename>/proc/cmdline</filename>
+ instead.</para></footnote>:</para>
+
+ <variablelist>
+ <varlistentry>
+ <term><varname>systemd.unit=</varname></term>
+ <term><varname>rd.systemd.unit=</varname></term>
+
+ <listitem><para>Overrides the unit to
+ activate on boot. Defaults to
+ <filename>default.target</filename>. This
+ may be used to temporarily boot into a
+ different boot unit, for example
+ <filename>rescue.target</filename> or
+ <filename>emergency.service</filename>. See
+ <citerefentry><refentrytitle>systemd.special</refentrytitle><manvolnum>7</manvolnum></citerefentry>
+ for details about these units. The
+ option prefixed with
+ <literal>rd.</literal> is honored
+ only in the initial RAM disk (initrd),
+ while the one that isn't prefixed only
+ in the main system.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.dump_core=</varname></term>
+
+ <listitem><para>Takes a boolean
+ argument. If <option>true</option>
+ systemd dumps core when it
+ crashes. Otherwise no core dump is
+ created. Defaults to
+ <option>true</option>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.crash_shell=</varname></term>
+
+ <listitem><para>Takes a boolean
+ argument. If <option>true</option>
+ systemd spawns a shell when it
+ crashes. Otherwise no shell is
+ spawned. Defaults to
+ <option>false</option>, for security
+ reasons, as the shell is not protected
+ by any password
+ authentication.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.crash_chvt=</varname></term>
+
+ <listitem><para>Takes an integer
+ argument. If positive systemd
+ activates the specified virtual
+ terminal when it crashes. Defaults to
+ <literal>-1</literal>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.confirm_spawn=</varname></term>
+
+ <listitem><para>Takes a boolean
+ argument. If <option>true</option>
+ asks for confirmation when spawning
+ processes. Defaults to
+ <option>false</option>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.show_status=</varname></term>
+
+ <listitem><para>Takes a boolean
+ argument. If <option>true</option>
+ shows terse service status updates on
+ the console during bootup. Defaults to
+ <option>true</option>, unless
+ <option>quiet</option> is passed as
+ kernel command line option in which
+ case it defaults to
+ <option>false</option>.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.log_target=</varname></term>
+ <term><varname>systemd.log_level=</varname></term>
+ <term><varname>systemd.log_color=</varname></term>
+ <term><varname>systemd.log_location=</varname></term>
+
+ <listitem><para>Controls log output,
+ with the same effect as the
+ <varname>$SYSTEMD_LOG_TARGET</varname>, <varname>$SYSTEMD_LOG_LEVEL</varname>, <varname>$SYSTEMD_LOG_COLOR</varname>, <varname>$SYSTEMD_LOG_LOCATION</varname>
+ environment variables described above.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.default_standard_output=</varname></term>
+ <term><varname>systemd.default_standard_error=</varname></term>
+ <listitem><para>Controls default
+ standard output and error output for
+ services, with the same effect as the
+ <option>--default-standard-output=</option>
+ and <option>--default-standard-error=</option>
+ command line arguments described
+ above, respectively.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>systemd.setenv=</varname></term>
+
+ <listitem><para>Takes a string
+ argument in the form
+ VARIABLE=VALUE. May be used to set
+ environment variables for the init
+ process and all its children at boot
+ time. May be used more than once to
+ set multiple variables. If the equal
+ sign and variable are missing it unsets
+ an environment variable which might be
+ passed in from the initial ram
+ disk.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>quiet</varname></term>
+
+ <listitem><para>If passed turns off
+ status output at boot, much like
+ <varname>systemd.show_status=false</varname>
+ would. Note that this option is also
+ read by the kernel itself and disables
+ kernel log output to the
+ kernel. Passing this option hence
+ turns off the usual output from both
+ the system manager and the
+ kernel.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>emergency</varname></term>
+
+ <listitem><para>Boot into emergency
+ mode. This is equivalent to
+ <varname>systemd.unit=emergency.target</varname>
+ and provided for compatibility
+ reasons and to be easier to type.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>single</varname></term>
+ <term><varname>s</varname></term>
+ <term><varname>S</varname></term>
+ <term><varname>1</varname></term>
+
+ <listitem><para>Boot into rescue
+ mode. This is equivalent to
+ <varname>systemd.unit=rescue.target</varname>
+ and provided for compatibility reasons
+ and to be easier to
+ type.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>2</varname></term>
+ <term><varname>3</varname></term>
+ <term><varname>4</varname></term>
+ <term><varname>5</varname></term>
+
+ <listitem><para>Boot into the
+ specified legacy SysV runlevel. These
+ are equivalent to
+ <varname>systemd.unit=runlevel2.target</varname>,
+ <varname>systemd.unit=runlevel3.target</varname>,
+ <varname>systemd.unit=runlevel4.target</varname>,
+ and <varname>systemd.unit=runlevel5.target</varname>, respectively,
+ and provided for compatibility reasons
+ and to be easier to
+ type.</para></listitem>
+ </varlistentry>
+
+ <varlistentry>
+ <term><varname>locale.LANG=</varname></term>
+ <term><varname>locale.LANGUAGE=</varname></term>
+ <term><varname>locale.LC_CTYPE=</varname></term>
+ <term><varname>locale.LC_NUMERIC=</varname></term>
+ <term><varname>locale.LC_TIME=</varname></term>
+ <term><varname>locale.LC_COLLATE=</varname></term>
+ <term><varname>locale.LC_MONETARY=</varname></term>
+ <term><varname>locale.LC_MESSAGES=</varname></term>
+ <term><varname>locale.LC_PAPER=</varname></term>
+ <term><varname>locale.LC_NAME=</varname></term>
+ <term><varname>locale.LC_ADDRESS=</varname></term>
+ <term><varname>locale.LC_TELEPHONE=</varname></term>
+ <term><varname>locale.LC_MEASUREMENT=</varname></term>
+ <term><varname>locale.LC_IDENTIFICATION=</varname></term>
+
+ <listitem><para>Set the system locale
+ to use. This overrides the settings in
+ <filename>/etc/locale.conf</filename>. For
+ more information see
+ <citerefentry><refentrytitle>locale.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ and
+ <citerefentry><refentrytitle>locale</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
+ </para></listitem>
+ </varlistentry>
+ </variablelist>
+
+ <para>For other kernel command line parameters
+ understood by components of the core OS, please refer
+ to
+ <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
+ </refsect1>
+