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<refentry id="kernel-command-line">

<refentryinfo>

<title>kernel-command-line</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>kernel-command-line</refentrytitle>

<manvolnum>7</manvolnum>

</refmeta>

<refnamediv>

<refname>kernel-command-line</refname>

<refpurpose>Kernel command line parameters</refpurpose>

</refnamediv>

<refsynopsisdiv>

<para><filename>/proc/cmdline</filename></para>

</refsynopsisdiv>

<refsect1>

<title>Description</title>

<para>The kernel, the initial RAM disk (initrd) and

basic userspace functionality may be configured at boot via

kernel command line arguments.</para>

<para>For command line parameters understood by the

kernel, please see <ulink

url="https://www.kernel.org/doc/Documentation/kernel-parameters.txt"><filename>kernel-parameters.txt</filename></ulink>

and

<citerefentry><refentrytitle>bootparam</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>

<para>For command line parameters understood by the

initial RAM disk, please see

<citerefentry><refentrytitle>dracut.cmdline</refentrytitle><manvolnum>7</manvolnum></citerefentry>,

or the documentation of the specific initrd

implementation of your installation.</para>

</refsect1>

<refsect1>

<title>Core OS Command Line Arguments</title>

<variablelist class='kernel-commandline-options'>

<varlistentry>

<term><varname>systemd.unit=</varname></term>

<term><varname>rd.systemd.unit=</varname></term>

<term><varname>systemd.dump_core=</varname></term>

<term><varname>systemd.crash_shell=</varname></term>

<term><varname>systemd.crash_chvt=</varname></term>

<term><varname>systemd.confirm_spawn=</varname></term>

<term><varname>systemd.show_status=</varname></term>

<term><varname>systemd.log_target=</varname></term>

<term><varname>systemd.log_level=</varname></term>

<term><varname>systemd.log_color=</varname></term>

<term><varname>systemd.log_location=</varname></term>

<term><varname>systemd.default_standard_output=</varname></term>

<term><varname>systemd.default_standard_error=</varname></term>

<term><varname>systemd.setenv=</varname></term>

<listitem>

<para>Parameters understood by

the system and service manager

to control system behavior. For details, see

<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>systemd.restore_state=</varname></term>

<listitem>

<para>This parameter is understood by

several system tools to control

whether or not they should restore

system state from the previous boot.

For details, see

<citerefentry><refentrytitle>systemd-backlight@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>

and

<citerefentry><refentrytitle>systemd-rfkill@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.

</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>quiet</varname></term>

<listitem>

<para>Parameter understood by

both the kernel and the system

and service manager to control

console log verbosity. For

details, see

<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>debug</varname></term>

<listitem>

<para>Parameter understood by

both the kernel and the system

and service manager to control

console log verbosity. For

details, see

<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>-b</varname></term>

<term><varname>emergency</varname></term>

<term><varname>single</varname></term>

<term><varname>s</varname></term>

<term><varname>S</varname></term>

<term><varname>1</varname></term>

<term><varname>2</varname></term>

<term><varname>3</varname></term>

<term><varname>4</varname></term>

<term><varname>5</varname></term>

<listitem>

<para>Parameters understood by

the system and service

manager, as compatibility

options. For details, see

<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>locale.LANG=</varname></term>

<term><varname>locale.LANGUAGE=</varname></term>

<term><varname>locale.LC_CTYPE=</varname></term>

<term><varname>locale.LC_NUMERIC=</varname></term>

<term><varname>locale.LC_TIME=</varname></term>

<term><varname>locale.LC_COLLATE=</varname></term>

<term><varname>locale.LC_MONETARY=</varname></term>

<term><varname>locale.LC_MESSAGES=</varname></term>

<term><varname>locale.LC_PAPER=</varname></term>

<term><varname>locale.LC_NAME=</varname></term>

<term><varname>locale.LC_ADDRESS=</varname></term>

<term><varname>locale.LC_TELEPHONE=</varname></term>

<term><varname>locale.LC_MEASUREMENT=</varname></term>

<term><varname>locale.LC_IDENTIFICATION=</varname></term>

<listitem>

<para>Parameters understood by

the system and service manager

to control locale and language

settings. For details, see

<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>fsck.mode=</varname></term>

<listitem>

<para>Parameter understood by

the file system checker

services. For details, see

<citerefentry><refentrytitle>systemd-fsck@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>quotacheck.mode=</varname></term>

<listitem>

<para>Parameter understood by

the file quota checker

service. For details, see

<citerefentry><refentrytitle>systemd-quotacheck.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>systemd.journald.forward_to_syslog=</varname></term>

<term><varname>systemd.journald.forward_to_kmsg=</varname></term>

<term><varname>systemd.journald.forward_to_console=</varname></term>

<term><varname>systemd.journald.forward_to_wall=</varname></term>

<listitem>

<para>Parameters understood by

the journal service. For

details, see

<citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>vconsole.keymap=</varname></term>

<term><varname>vconsole.keymap.toggle=</varname></term>

<term><varname>vconsole.font=</varname></term>

<term><varname>vconsole.font.map=</varname></term>

<term><varname>vconsole.font.unimap=</varname></term>

<listitem>

<para>Parameters understood by

the virtual console setup logic. For

details, see

<citerefentry><refentrytitle>systemd-vconsole-setup.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>udev.log-priority=</varname></term>

<term><varname>rd.udev.log-priority=</varname></term>

<term><varname>udev.children-max=</varname></term>

<term><varname>rd.udev.children-max=</varname></term>

<term><varname>udev.exec-delay=</varname></term>

<term><varname>rd.udev.exec-delay=</varname></term>

<term><varname>net.ifnames=</varname></term>

<listitem>

<para>Parameters understood by

the device event managing daemon. For

details, see

<citerefentry><refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>plymouth.enable=</varname></term>

<listitem>

<para>May be used to disable

the Plymouth boot splash. For

details, see

<citerefentry><refentrytitle>plymouth</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>luks=</varname></term>

<term><varname>rd.luks=</varname></term>

<term><varname>luks.crypttab=</varname></term>

<term><varname>rd.luks.crypttab=</varname></term>

<term><varname>luks.uuid=</varname></term>

<term><varname>rd.luks.uuid=</varname></term>

<term><varname>luks.options=</varname></term>

<term><varname>rd.luks.options=</varname></term>

<term><varname>luks.key=</varname></term>

<term><varname>rd.luks.key=</varname></term>

<listitem>

<para>Configures the LUKS

full-disk encryption logic at

boot. For details, see

<citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>fstab=</varname></term>

<term><varname>rd.fstab=</varname></term>

<listitem>

<para>Configures the

<filename>/etc/fstab</filename>

logic at boot. For details, see

<citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>

</listitem>

</varlistentry>

<varlistentry>

<term><varname>modules-load=</varname></term>

<term><varname>rd.modules-load=</varname></term>

<listitem>

<para>Load a specific kernel

module early at boot. For

details, see

<citerefentry><refentrytitle>systemd-modules-load.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>

</listitem>

</varlistentry>

</variablelist>

</refsect1>

<refsect1>

<title>See Also</title>

<para>

<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,

<citerefentry><refentrytitle>bootparam</refentrytitle><manvolnum>7</manvolnum></citerefentry>,

<citerefentry><refentrytitle>dracut.cmdline</refentrytitle><manvolnum>7</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd-fsck@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd-quotacheck.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd-vconsole-setup.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,

<citerefentry><refentrytitle>plymouth</refentrytitle><manvolnum>8</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,

<citerefentry><refentrytitle>systemd-modules-load.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>

<citerefentry><refentrytitle>systemd-backlight@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>

<citerefentry><refentrytitle>systemd-rfkill@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>

</para>

</refsect1>

</refentry>