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<?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">
<!--
  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="sysusers.d">

        <refentryinfo>
                <title>sysusers.d</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>sysusers.d</refentrytitle>
                <manvolnum>5</manvolnum>
        </refmeta>

        <refnamediv>
                <refname>sysusers.d</refname>
                <refpurpose>Declarative allocation of system users and groups</refpurpose>
        </refnamediv>

        <refsynopsisdiv>
                <para><filename>/usr/lib/sysusers.d/*.conf</filename></para>
        </refsynopsisdiv>

        <refsect1>
                <title>Description</title>

                <para><command>systemd-sysusers</command> uses the
                files from <filename>/usr/lib/sysusers.d/</filename>
                to create system users and groups at package
                installation or boot time. This tool may be used for
                allocating system users and groups only, it is not
                useful for creating non-system users and groups, as it
                accessed <filename>/etc/passwd</filename> and
                <filename>/etc/group</filename> directly, bypassing
                any more complex user database, for example any
                database involving NIS or LDAP.</para>

        </refsect1>

        <refsect1>
                <title>File Format</title>

                <para>Each file shall be named in the style of
                <filename><replaceable>package</replaceable>.conf</filename>.</para>

                <para>All files are sorted by their filename in
                lexicographic order, regardless of which of the
                directories they reside in. If multiple files specify
                the same user or group, the entry in the file with the
                lexicographically earliest name will be applied, all
                all other conflicting entries will be logged as
                errors. Users and groups are
                processed in the order they are listed.</para>

                <para>The file format is one line per user or group
                containing name, ID and GECOS field description:</para>

                <programlisting># Type Name ID GECOS
u httpd 440 "HTTP User"
u authd /usr/bin/authd "Authorization user"
g input - -
m authd input</programlisting>

                <refsect2>
                        <title>Type</title>

                        <para>The type consists of a single
                        letter. The following line types are
                        understood:</para>

                        <variablelist>
                                <varlistentry>
                                        <term><varname>u</varname></term>
                                        <listitem><para>Create a
                                        system user and group of the
                                        specified name should they not
                                        exist yet. The user's primary
                                        group will be set to the group
                                        bearing the same name. The
                                        user's shell will be set to
                                        <filename>/sbin/login</filename>,
                                        the home directory to
                                        <filename>/</filename>. The
                                        account will be created
                                        disabled, so that logins are
                                        not allowed.</para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>g</varname></term>
                                        <listitem><para>Create a
                                        system group of the specified
                                        name should it not exist
                                        yet. Note that
                                        <varname>u</varname>
                                        implicitly create a matching
                                        group. The group will be
                                        created with no password
                                        set.</para></listitem>
                                </varlistentry>

                                <varlistentry>
                                        <term><varname>m</varname></term>
                                        <listitem><para>Add a user to
                                        a group. If the user or group
                                        are not existing yet, they
                                        will be implicitly
                                        created.</para></listitem>
                                </varlistentry>
                        </variablelist>
                </refsect2>

                <refsect2>
                        <title>Name</title>

                        <para>The name field specifies the user or
                        group name. It should be be shorter than 256
                        characters and avoid any non-ASCII characters,
                        and not begin with a numeric character. It is
                        strongly recommended to pick user and group
                        names that are unlikely to clash with normal
                        users created by the administrator. A good
                        scheme to guarantee this is by prefixing all
                        system and group names with the underscore,
                        and avoiding too generic names.</para>

                        <para>For <varname>m</varname> lines this
                        field should contain the user name to add to a
                        group.</para>
                </refsect2>

                <refsect2>
                        <title>ID</title>

                        <para>For <varname>u</varname> and
                        <varname>g</varname> the numeric 32bit UID or
                        GID of the user/group. Do not use IDs 65535 or
                        4294967295, as they have special placeholder
                        meanings. Specify "-" for automatic UID/GID
                        allocation for the user or
                        group. Alternatively, specify an absolute path
                        in the file system. In this case the UID/GID
                        is read from the path's owner/group. This is
                        useful to create users whose UID/GID match the
                        owners of pre-existing files (such as SUID or
                        SGID binaries).</para>

                        <para>For <varname>m</varname> lines this
                        field should contain the group name to add to
                        a user to.</para>
                </refsect2>

                <refsect2>
                        <title>GECOS</title>

                        <para>A short, descriptive string for users to
                        be created, enclosed in quotation marks. Note
                        that this field may not contain colons.</para>

                        <para>Only applies to lines of type
                        <varname>u</varname> and should otherwise be
                        left unset.</para>
                </refsect2>

        </refsect1>

        <refsect1>
                <title>See Also</title>
                <para>
                        <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
                        <citerefentry><refentrytitle>systemd-sysusers</refentrytitle><manvolnum>8</manvolnum></citerefentry>
                </para>
        </refsect1>

</refentry>