systemd/man/systemd-debug-generator.xml

<?xml version="1.0"?>
<!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd" [
<!ENTITY % entities SYSTEM "custom-entities.ent" >
%entities;
]>
<!--
  This file is part of systemd.

  Copyright 2014 Lennart Poettering

  systemd is free software; you can redistribute it and/or modify it
  under the terms of the GNU Lesser General Public License as published by
  the Free Software Foundation; either version 2.1 of the License, or
  (at your option) any later version.

  systemd is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public License
  along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<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>&rootlibexecdir;/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 or 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
    <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</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>