man/systemd-debug-generator.xml

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   3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!--
   5   SPDX-License-Identifier: LGPL-2.1+
   6
   7   This file is part of systemd.
   8
   9   Copyright 2014 Lennart Poettering
  10 -->
  11 <refentry id="systemd-debug-generator">
  12
  13   <refentryinfo>
  14     <title>systemd-debug-generator</title>
  15     <productname>systemd</productname>
  16
  17     <authorgroup>
  18       <author>
  19         <contrib>Developer</contrib>
  20         <firstname>Lennart</firstname>
  21         <surname>Poettering</surname>
  22         <email>lennart@poettering.net</email>
  23       </author>
  24     </authorgroup>
  25   </refentryinfo>
  26
  27   <refmeta>
  28     <refentrytitle>systemd-debug-generator</refentrytitle>
  29     <manvolnum>8</manvolnum>
  30   </refmeta>
  31
  32   <refnamediv>
  33     <refname>systemd-debug-generator</refname>
  34     <refpurpose>Generator for enabling a runtime debug shell and
  35     masking specific units at boot</refpurpose>
  36   </refnamediv>
  37
  38   <refsynopsisdiv>
  39     <para><filename>/usr/lib/systemd/system-generators/systemd-debug-generator</filename></para>
  40   </refsynopsisdiv>
  41
  42   <refsect1>
  43     <title>Description</title>
  44
  45     <para><filename>systemd-debug-generator</filename> is a generator
  46     that reads the kernel command line and understands three
  47     options:</para>
  48
  49     <para>If the <option>systemd.mask=</option> option is specified
  50     and followed by a unit name, this unit is masked for the runtime,
  51     similar to the effect of
  52     <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
  53     <command>mask</command> command. This is useful to boot with
  54     certain units removed from the initial boot transaction for
  55     debugging system startup. May be specified more than once.</para>
  56
  57     <para>If the <option>systemd.wants=</option> option is specified
  58     and followed by a unit name, a start job for this unit is added to
  59     the initial transaction. This is useful to start one or more
  60     additional units at boot. May be specified more than once.</para>
  61
  62     <para>If the <option>systemd.debug_shell</option> option is
  63     specified, the debug shell service
  64     <literal>debug-shell.service</literal> is pulled into the boot
  65     transaction. It will spawn a debug shell on tty9 during early
  66     system startup. Note that the shell may also be turned on
  67     persistently by enabling it with
  68     <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
  69     <command>enable</command> command.</para>
  70
  71     <para><filename>systemd-debug-generator</filename> implements
  72     <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
  73   </refsect1>
  74
  75   <refsect1>
  76     <title>See Also</title>
  77     <para>
  78       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  79       <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  80       <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>
  81     </para>
  82   </refsect1>
  83
  84 </refentry>