3 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
5 This file is part of systemd.
7 Copyright 2014 Lennart Poettering
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
11 the Free Software Foundation; either version 2.1 of the License, or
12 (at your option) any later version.
14 systemd is distributed in the hope that it will be useful, but
15 WITHOUT ANY WARRANTY; without even the implied warranty of
16 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
17 Lesser General Public License for more details.
19 You should have received a copy of the GNU Lesser General Public License
20 along with systemd; If not, see <http://www.gnu.org/licenses/>.
22 <refentry id="systemd-debug-generator">
25 <title>systemd-debug-generator</title>
26 <productname>systemd</productname>
30 <contrib>Developer</contrib>
31 <firstname>Lennart</firstname>
32 <surname>Poettering</surname>
33 <email>lennart@poettering.net</email>
39 <refentrytitle>systemd-debug-generator</refentrytitle>
40 <manvolnum>8</manvolnum>
44 <refname>systemd-debug-generator</refname>
45 <refpurpose>Generator for enabling a runtime debug shell and masking specific units at boot</refpurpose>
49 <para><filename>/usr/lib/systemd/system-generators/systemd-debug-generator</filename></para>
53 <title>Description</title>
55 <para><filename>systemd-debug-generator</filename> is
56 a generator that reads the kernel command line and understands two options:</para>
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>
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>
75 <para><filename>systemd-debug-generator</filename>
77 url="http://www.freedesktop.org/wiki/Software/systemd/Generators">generator
78 specification</ulink>.</para>
82 <title>See Also</title>
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>