systemd/man/runlevel.xml

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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
        "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

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<refentry id="runlevel"
          xmlns:xi="http://www.w3.org/2001/XInclude">

        <refentryinfo>
                <title>runlevel</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>runlevel</refentrytitle>
                <manvolnum>8</manvolnum>
        </refmeta>

        <refnamediv>
                <refname>runlevel</refname>
                <refpurpose>Print previous and current SysV runlevel</refpurpose>
        </refnamediv>

        <refsynopsisdiv>
                <cmdsynopsis>
                        <command>runlevel <arg choice="opt" rep="repeat">options</arg></command>
                </cmdsynopsis>
        </refsynopsisdiv>

        <refsect1>
                <title>Description</title>

                <para><command>runlevel</command> prints the previous
                and current SysV runlevel if they are known.</para>

                <para>The two runlevel characters are separated by a
                single space character. If a runlevel cannot be
                determined, N is printed instead. If neither can be
                determined, the word "unknown" is printed.</para>

                <para>Unless overridden in the environment, this will
                check the utmp database for recent runlevel
                changes.</para>
        </refsect1>

        <refsect1>
                <title>Options</title>

                <para>The following option is understood:</para>

                <variablelist>
                        <varlistentry>
                                <term><option>--help</option></term>

                                <xi:include href="standard-options.xml" xpointer="help-text" />
                        </varlistentry>
                </variablelist>

        </refsect1>

        <refsect1>
                <title>Exit status</title>

                <para>If one or both runlevels could be determined, 0
                is returned, a non-zero failure code otherwise.</para>

        </refsect1>

        <refsect1>
                <title>Environment</title>

                <variablelist class='environment-variables'>
                        <varlistentry>
                                <term><varname>$RUNLEVEL</varname></term>

                                <listitem><para>If
                                <varname>$RUNLEVEL</varname> is set,
                                <command>runlevel</command> will print
                                this value as current runlevel and
                                ignore utmp.</para></listitem>
                        </varlistentry>

                        <varlistentry>
                                <term><varname>$PREVLEVEL</varname></term>

                                <listitem><para>If
                                <varname>$PREVLEVEL</varname> is set,
                                <command>runlevel</command> will print
                                this value as previous runlevel and
                                ignore utmp.</para></listitem>
                        </varlistentry>
                </variablelist>
        </refsect1>

        <refsect1>
                <title>Files</title>

                <variablelist>
                        <varlistentry>
                                <term><filename>/var/run/utmp</filename></term>

                                <listitem><para>The utmp database
                                <command>runlevel</command> reads the
                                previous and current runlevel
                                from.</para></listitem>

                        </varlistentry>
                </variablelist>
        </refsect1>

        <refsect1>
                <title>Notes</title>

                <para>This is a legacy command available for compatibility
                only. It should not be used anymore, as the concept of
                runlevels is obsolete.</para>
        </refsect1>

        <refsect1>
                <title>See Also</title>
                <para>
                        <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
                        <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
                </para>
        </refsect1>

</refentry>