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.
   6
   7   Copyright 2014 Lennart Poettering
   8
   9   systemd is free software; you can redistribute it and/or modify it
  10   under the terms of the GNU Lesser General Public License as published by
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  20   along with systemd; If not, see <http://www.gnu.org/licenses/>.
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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
  57                 understands three options:</para>
  58
  59                 <para>If the <option>systemd.mask=</option> option is
  60                 specified and followed by a unit name, this unit is
  61                 masked for the runtime, similar to the effect of
  62                 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
  63                 <command>mask</command> command. This is useful to
  64                 boot with certain units removed from the initial boot
  65                 transaction for debugging system startup. May be
  66                 specified more than once.</para>
  67
  68                 <para>If the <option>systemd.wants=</option> option is
  69                 specified and followed by a unit name, a start job for
  70                 this unit is added to the initial transaction. This is
  71                 useful to start one ore more additional units at
  72                 boot. May be specified more than once.</para>
  73
  74                 <para>If the <option>systemd.debug-shell</option>
  75                 option is specified, the debug shell service
  76                 <literal>debug-shell.service</literal> is pulled into
  77                 the boot transaction. It will spawn a debug shell on
  78                 tty9 during early system startup. Note that the shell
  79                 may also be turned on persistently by enabling it with
  80                 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
  81                 <command>enable</command> command.</para>
  82
  83                 <para><filename>systemd-debug-generator</filename>
  84                 implements the <ulink
  85                 url="http://www.freedesktop.org/wiki/Software/systemd/Generators">generator
  86                 specification</ulink>.</para>
  87         </refsect1>
  88
  89         <refsect1>
  90                 <title>See Also</title>
  91                 <para>
  92                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  93                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  94                         <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>
  95                 </para>
  96         </refsect1>
  97
  98 </refentry>