travis: use UBSan checks from OSS-Fuzz

[thirdparty/systemd.git] / man / hostnamectl.xml

<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1+ -->

<refentry id="hostnamectl" conditional='ENABLE_HOSTNAMED'
    xmlns:xi="http://www.w3.org/2001/XInclude">

  <refentryinfo>
    <title>hostnamectl</title>
    <productname>systemd</productname>
  </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 fallback
    value 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 and length used, while the static and
    transient hostnames are limited to the usually accepted characters of Internet domain names, and 64 characters at
    maximum (the latter being a Linux limitation).</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-info</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>

    <para>Use
    <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    to initialize the system host name for mounted (but not booted)
    system images.</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>--static</option></term>
        <term><option>--transient</option></term>
        <term><option>--pretty</option></term>

        <listitem><para>If <command>status</command> is invoked (or no explicit command is given) and one of these
        switches is specified, <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 these switches are specified, all the specified hostnames will be updated. </para></listitem>
      </varlistentry>

      <xi:include href="user-system-options.xml" xpointer="host" />
      <xi:include href="user-system-options.xml" xpointer="machine" />

      <xi:include href="standard-options.xml" xpointer="help" />
      <xi:include href="standard-options.xml" xpointer="version" />
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Commands</title>

    <para>The following commands are understood:</para>

    <variablelist>
      <varlistentry>
        <term><command>status</command></term>

        <listitem><para>Show current system hostname and related information. If no command is specified,
        this is the implied default.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><command>set-hostname <replaceable>NAME</replaceable></command></term>

        <listitem><para>Set the system hostname to <replaceable>NAME</replaceable>. 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 removing special
        characters and spaces. 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.</para>

        <para>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 <replaceable>NAME</replaceable></command></term>

        <listitem><para>Set the system icon name to
        <replaceable>NAME</replaceable>. 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>.</para>

        <para>Pass an empty string 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 <replaceable>TYPE</replaceable></command></term>

        <listitem><para>Set the chassis type to
        <replaceable>TYPE</replaceable>. 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>convertible</literal>,
        <literal>server</literal>,
        <literal>tablet</literal>,
        <literal>handset</literal>,
        <literal>watch</literal>,
        <literal>embedded</literal>,
        as well as the special chassis types
        <literal>vm</literal> and
        <literal>container</literal> for virtualized systems that lack
        an immediate physical chassis.</para>

        <para>Pass an empty string to reset the chassis type to the
        default value which is determined from the firmware and
        possibly other parameters.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>set-deployment <replaceable>ENVIRONMENT</replaceable></command></term>

        <listitem><para>Set the deployment environment description.
        <replaceable>ENVIRONMENT</replaceable> must be a single word
        without any control characters. One of the following is
        suggested:
        <literal>development</literal>,
        <literal>integration</literal>,
        <literal>staging</literal>,
        <literal>production</literal>.
        </para>

        <para>Pass an empty string to reset to the default empty
        value.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><command>set-location <replaceable>LOCATION</replaceable></command></term>

        <listitem><para>Set the location string for the system, if it
        is known. <replaceable>LOCATION</replaceable> should be a
        human-friendly, free-form string describing the physical
        location of the system, if it is known and applicable. This
        may be as generic as <literal>Berlin, Germany</literal> or as
        specific as <literal>Left Rack, 2nd Shelf</literal>.</para>

        <para>Pass an empty string to reset to the default empty
        value.</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>,
      <citerefentry><refentrytitle>systemd-firstboot</refentrytitle><manvolnum>1</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>