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systemd/man/hostnamectl.xml
Stef Walter c779a44222 hostnamed: Fix the way that static and transient host names interact
It is almost always incorrect to allow DHCP or other sources of
transient host names to override an explicitly configured static host
name.

This commit changes things so that if a static host name is set, this
will override the transient host name (eg: provided via DHCP). Transient
host names can still be used to provide host names for machines that have
not been explicitly configured with a static host name.

The exception to this rule is if the static host name is set to
"localhost". In those cases we act as if no
static host name has been explicitly set.

As discussed elsewhere, systemd may want to have an fd based ownership
of the transient name. That part is not included in this commit.
2014-05-28 09:34:37 +08:00

252 lines
12 KiB
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">
<!--
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Copyright 2012 Lennart Poettering
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You should have received a copy of the GNU Lesser General Public License
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-->
<refentry id="hostnamectl" conditional='ENABLE_HOSTNAMED'
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>hostnamectl</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>hostnamectl</refentrytitle>
<manvolnum>1</manvolnum>
</refmeta>
<refnamediv>
<refname>hostnamectl</refname>
<refpurpose>Control the system hostname</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>hostnamectl</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<arg choice="req">COMMAND</arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><command>hostnamectl</command> may be used to
query and change the system hostname and related
settings.</para>
<para>This tool distinguishes three different
hostnames: the high-level "pretty" hostname which
might include all kinds of special characters
(e.g. "Lennart's Laptop"), the static hostname which
is used to initialize the kernel hostname at boot
(e.g. "lennarts-laptop"), and the transient hostname
which is a default received from network configuration.
If a static hostname is set, and is valid (something other
than localhost) then the transient hostname is not used.</para>
<para>Note that the pretty hostname has little
restrictions on the characters used, while the static
and transient hostnames are limited to the usually
accepted characters of Internet domain names.</para>
<para>The static hostname is stored in
<filename>/etc/hostname</filename>, see
<citerefentry><refentrytitle>hostname</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for more information. The pretty hostname, chassis
type, and icon name are stored in
<filename>/etc/machine-info</filename>, see
<citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
</refsect1>
<refsect1>
<title>Options</title>
<para>The following options are understood:</para>
<variablelist>
<varlistentry>
<term><option>--no-ask-password</option></term>
<listitem><para>Do not query the user
for authentication for privileged
operations.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-P</option></term>
<term><option>--privileged</option></term>
<listitem><para>Acquire privileges via PolicyKit
before executing the operation.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--static</option></term>
<term><option>--transient</option></term>
<term><option>--pretty</option></term>
<listitem><para>If
<command>status</command> is used (or
no explicit command is given) and one
of those fields is given,
<command>hostnamectl</command> will
print out just this selected
hostname.</para>
<para>If used with
<command>set-hostname</command>, only
the selected hostname(s) will be
updated. When more than one of those
options is used, all the specified
hostnames will be updated.
</para></listitem>
</varlistentry>
<xi:include href="user-system-options.xml" xpointer="host" />
<xi:include href="standard-options.xml" xpointer="help" />
<xi:include href="standard-options.xml" xpointer="version" />
</variablelist>
<para>The following commands are understood:</para>
<variablelist>
<varlistentry>
<term><command>status</command></term>
<listitem><para>Show current system
hostname and related
information.</para></listitem>
</varlistentry>
<varlistentry>
<term><command>set-hostname [NAME]</command></term>
<listitem><para>Set the system
hostname. By default, this will alter
the pretty, the static, and the
transient hostname alike; however, if
one or more of
<option>--static</option>,
<option>--transient</option>,
<option>--pretty</option> are used,
only the selected hostnames are
changed. If the pretty hostname is
being set, and static or transient are
being set as well, the specified
hostname will be simplified in regards
to the character set used before the
latter are updated. This is done by
replacing spaces with
<literal>-</literal> and removing
special characters. This ensures that
the pretty and the static hostname are
always closely related while still
following the validity rules of the
specific name. This simplification of
the hostname string is not done if
only the transient and/or static host
names are set, and the pretty host
name is left untouched. Pass the empty
string <literal></literal> as the
hostname to reset the selected
hostnames to their default (usually
<literal>localhost</literal>).</para></listitem>
</varlistentry>
<varlistentry>
<term><command>set-icon-name [NAME]</command></term>
<listitem><para>Set the system icon
name. The icon name is used by some
graphical applications to visualize
this host. The icon name should follow
the <ulink
url="http://standards.freedesktop.org/icon-naming-spec/icon-naming-spec-latest.html">Icon
Naming Specification</ulink>. Pass an
empty string to this operation to
reset the icon name to the default
value, which is determined from chassis
type (see below) and possibly other
parameters.</para></listitem>
</varlistentry>
<varlistentry>
<term><command>set-chassis [TYPE]</command></term>
<listitem><para>Set the chassis
type. The chassis type is used by some
graphical applications to visualize
the host or alter user
interaction. Currently, the following
chassis types are defined:
<literal>desktop</literal>,
<literal>laptop</literal>,
<literal>server</literal>,
<literal>tablet</literal>,
<literal>handset</literal>, as well as
the special chassis types
<literal>vm</literal> and
<literal>container</literal> for
virtualized systems that lack an
immediate physical chassis. Pass an
empty string to this operation to
reset the chassis type to the default
value which is determined from the
firmware and possibly other
parameters.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Exit status</title>
<para>On success, 0 is returned, a non-zero failure
code otherwise.</para>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>hostname</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>hostname</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>machine-info</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-hostnamed.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>