man/systemd-debug-generator.xml

   1 <?xml version="1.0"?>
   2 <!--*-nxml-*-->
   3 <!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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   5   This file is part of systemd.
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   7   Copyright 2014 Lennart Poettering
   8
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  22 <refentry id="systemd-debug-generator">
  23
  24         <refentryinfo>
  25                 <title>systemd-debug-generator</title>
  26                 <productname>systemd</productname>
  27
  28                 <authorgroup>
  29                         <author>
  30                                 <contrib>Developer</contrib>
  31                                 <firstname>Lennart</firstname>
  32                                 <surname>Poettering</surname>
  33                                 <email>lennart@poettering.net</email>
  34                         </author>
  35                 </authorgroup>
  36         </refentryinfo>
  37
  38         <refmeta>
  39                 <refentrytitle>systemd-debug-generator</refentrytitle>
  40                 <manvolnum>8</manvolnum>
  41         </refmeta>
  42
  43         <refnamediv>
  44                 <refname>systemd-debug-generator</refname>
  45                 <refpurpose>Generator for enabling a runtime debug shell and masking specific units at boot</refpurpose>
  46         </refnamediv>
  47
  48         <refsynopsisdiv>
  49                 <para><filename>/usr/lib/systemd/system-generators/systemd-debug-generator</filename></para>
  50         </refsynopsisdiv>
  51
  52         <refsect1>
  53                 <title>Description</title>
  54
  55                 <para><filename>systemd-debug-generator</filename> is
  56                 a generator that reads the kernel command line and understands two options:</para>
  57
  58                 <para>If the <option>systemd.mask=</option> option is
  59                 specified and followed by a unit name this unit is
  60                 masked for the runtime, similar to the effect of
  61                 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
  62                 <command>mask</command> command. This is useful to
  63                 boot with certain units removed from the initial boot
  64                 transaction for debugging system startup.</para>
  65
  66                 <para>If the <option>systemd.debug-shell</option>
  67                 option is specified the debug shell service
  68                 <literal>debug-shell.service</literal> is pulled into
  69                 the boot transaction. It will spawn a debug shell on
  70                 tty9 during early system startup. Note that the shell
  71                 may also be turned on persistently by enabling it with
  72                 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
  73                 <command>enable</command> command.</para>
  74
  75                 <para><filename>systemd-debug-generator</filename>
  76                 implements the <ulink
  77                 url="http://www.freedesktop.org/wiki/Software/systemd/Generators">generator
  78                 specification</ulink>.</para>
  79         </refsect1>
  80
  81         <refsect1>
  82                 <title>See Also</title>
  83                 <para>
  84                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  85                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  86                         <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>
  87                 </para>
  88         </refsect1>
  89
  90 </refentry>