systemd/man/systemd-debug-generator.xml

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<refentry id="systemd-debug-generator">

        <refentryinfo>
                <title>systemd-debug-generator</title>
                <productname>systemd</productname>

                <authorgroup>
                        <author>
                                <contrib>Developer</contrib>
                                <firstname>Lennart</firstname>
                                <surname>Poettering</surname>
                                <email>lennart@poettering.net</email>
                        </author>
                </authorgroup>
        </refentryinfo>

        <refmeta>
                <refentrytitle>systemd-debug-generator</refentrytitle>
                <manvolnum>8</manvolnum>
        </refmeta>

        <refnamediv>
                <refname>systemd-debug-generator</refname>
                <refpurpose>Generator for enabling a runtime debug shell and masking specific units at boot</refpurpose>
        </refnamediv>

        <refsynopsisdiv>
                <para><filename>/usr/lib/systemd/system-generators/systemd-debug-generator</filename></para>
        </refsynopsisdiv>

        <refsect1>
                <title>Description</title>

                <para><filename>systemd-debug-generator</filename> is
                a generator that reads the kernel command line and
                understands three options:</para>

                <para>If the <option>systemd.mask=</option> option is
                specified and followed by a unit name, this unit is
                masked for the runtime, similar to the effect of
                <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
                <command>mask</command> command. This is useful to
                boot with certain units removed from the initial boot
                transaction for debugging system startup. May be
                specified more than once.</para>

                <para>If the <option>systemd.wants=</option> option is
                specified and followed by a unit name, a start job for
                this unit is added to the initial transaction. This is
                useful to start one ore more additional units at
                boot. May be specified more than once.</para>

                <para>If the <option>systemd.debug-shell</option>
                option is specified, the debug shell service
                <literal>debug-shell.service</literal> is pulled into
                the boot transaction. It will spawn a debug shell on
                tty9 during early system startup. Note that the shell
                may also be turned on persistently by enabling it with
                <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
                <command>enable</command> command.</para>

                <para><filename>systemd-debug-generator</filename>
                implements the <ulink
                url="http://www.freedesktop.org/wiki/Software/systemd/Generators">generator
                specification</ulink>.</para>
        </refsect1>

        <refsect1>
                <title>See Also</title>
                <para>
                        <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
                        <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
                        <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>
                </para>
        </refsect1>

</refentry>