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<?xml version='1.0'?>
< !DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!-- SPDX - License - Identifier: LGPL - 2.1 - or - later -->
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<refentry id= "userdbctl" conditional= 'ENABLE_USERDB'
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo >
<title > userdbctl</title>
<productname > systemd</productname>
</refentryinfo>
<refmeta >
<refentrytitle > userdbctl</refentrytitle>
<manvolnum > 1</manvolnum>
</refmeta>
<refnamediv >
<refname > userdbctl</refname>
<refpurpose > Inspect users, groups and group memberships</refpurpose>
</refnamediv>
<refsynopsisdiv >
<cmdsynopsis >
<command > userdbctl</command>
<arg choice= "opt" rep= "repeat" > OPTIONS</arg>
<arg choice= "req" > COMMAND</arg>
<arg choice= "opt" rep= "repeat" > NAME</arg>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1 >
<title > Description</title>
<para > <command > userdbctl</command> may be used to inspect user and groups (as well as group memberships)
of the system. This client utility inquires user/group information provided by various system services,
both operating on JSON user/group records (as defined by the <ulink
url="https://systemd.io/USER_RECORD">JSON User Record</ulink> and <ulink
url="https://systemd.io/GROUP_RECORD">JSON Group Record</ulink> definitions), and classic UNIX NSS/glibc
user and group records. This tool is primarily a client to the <ulink
url="https://systemd.io/USER_GROUP_API">User/Group Record Lookup API via Varlink</ulink> .</para>
</refsect1>
<refsect1 >
<title > Options</title>
<para > The following options are understood:</para>
<variablelist >
<varlistentry >
<term > <option > --output=</option> <replaceable > MODE</replaceable> </term>
<listitem > <para > Choose the output mode, takes one of <literal > classic</literal> ,
<literal > friendly</literal> , <literal > table</literal> , <literal > json</literal> . If
<literal > classic</literal> , an output very close to the format of <filename > /etc/passwd</filename> or
<filename > /etc/group</filename> is generated. If <literal > friendly</literal> a more comprehensive and
user friendly, human readable output is generated; if <literal > table</literal> a minimal, tabular
output is generated; if <literal > json</literal> a JSON formatted output is generated. Defaults to
<literal > friendly</literal> if a user/group is specified on the command line,
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<literal > table</literal> otherwise.</para>
<para > Note that most output formats do not show all available information. In particular,
<literal > classic</literal> and <literal > table</literal> show only the most important fields. Various
modes also do not show password hashes. Use <literal > json</literal> to view all fields, including
any authentication fields.</para>
</listitem>
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</varlistentry>
<varlistentry >
<term > <option > --service=</option> <replaceable > SERVICE</replaceable> <optional > :<replaceable > SERVICE…</replaceable> </optional> </term>
<term > <option > -s</option> <replaceable > SERVICE</replaceable> :<replaceable > SERVICE…</replaceable> </term>
<listitem > <para > Controls which services to query for users/groups. Takes a list of one or more
service names, separated by <literal > :</literal> . See below for a list of well-known service
names. If not specified all available services are queried at once.</para> </listitem>
</varlistentry>
<varlistentry >
<term > <option > --with-nss=</option> <replaceable > BOOL</replaceable> </term>
<listitem > <para > Controls whether to include classic glibc/NSS user/group lookups in the output. If
<option > --with-nss=no</option> is used any attempts to resolve or enumerate users/groups provided
only via glibc NSS is suppressed. If <option > --with-nss=yes</option> is specified such users/groups
are included in the output (which is the default).</para> </listitem>
</varlistentry>
<varlistentry >
<term > <option > --synthesize=</option> <replaceable > BOOL</replaceable> </term>
<listitem > <para > Controls whether to synthesize records for the root and nobody users/groups if they
aren't defined otherwise. By default (or <literal > yes</literal> ) such records are implicitly
synthesized if otherwise missing since they have special significance to the OS. When
<literal > no</literal> this synthesizing is turned off.</para> </listitem>
</varlistentry>
<varlistentry >
<term > <option > -N</option> </term>
<listitem > <para > This option is short for <option > --with-nss=no</option>
<option > --synthesize=no</option> . Use this option to show only records that are natively defined as
JSON user or group records, with all NSS/glibc compatibility and all implicit synthesis turned
off.</para> </listitem>
</varlistentry>
<xi:include href= "standard-options.xml" xpointer= "no-pager" />
<xi:include href= "standard-options.xml" xpointer= "no-legend" />
<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 > user</command> <optional > <replaceable > USER</replaceable> …</optional> </term>
<listitem > <para > List all known users records or show details of one or more specified user
records. Use <option > --output=</option> to tweak output mode.</para> </listitem>
</varlistentry>
<varlistentry >
<term > <command > group</command> <optional > <replaceable > GROUP</replaceable> …</optional> </term>
<listitem > <para > List all known group records or show details of one or more specified group
records. Use <option > --output=</option> to tweak output mode.</para> </listitem>
</varlistentry>
<varlistentry >
<term > <command > users-in-group</command> <optional > <replaceable > GROUP</replaceable> …</optional> </term>
<listitem > <para > List users that are members of the specified groups. If no groups are specified list
all user/group memberships defined. Use <option > --output=</option> to tweak output
mode.</para> </listitem>
</varlistentry>
<varlistentry >
<term > <command > groups-of-user</command> <optional > <replaceable > USER</replaceable> …</optional> </term>
<listitem > <para > List groups that the specified users are members of. If no users are specified list
all user/group memberships defined (in this case <command > groups-of-user</command> and
<command > users-in-group</command> are equivalent). Use <option > --output=</option> to tweak output
mode.</para> </listitem>
</varlistentry>
<varlistentry >
<term > <command > services</command> </term>
<listitem > <para > List all services currently providing user/group definitions to the system. See below
for a list of well-known services providing user information.</para> </listitem>
</varlistentry>
<varlistentry >
<term > <command > ssh-authorized-keys</command> </term>
<listitem > <para > This operation is not a public, user-facing interface. It is used to allow the SSH daemon to pick
up authorized keys from user records, see below.</para> </listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1 >
<title > Well-Known Services</title>
<para > The <command > userdbctl services</command> command will list all currently running services that
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provide user or group definitions to the system. The following well-known services are shown among
this list:</para>
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<variablelist >
<varlistentry >
<term > <constant > io.systemd.DynamicUser</constant> </term>
<listitem > <para > This service is provided by the system service manager itself (i.e. PID 1) and
makes all users (and their groups) synthesized through the <varname > DynamicUser=</varname> setting in
service unit files available to the system (see
<citerefentry > <refentrytitle > systemd.exec</refentrytitle> <manvolnum > 5</manvolnum> </citerefentry> for
details about this setting).</para> </listitem>
</varlistentry>
<varlistentry >
<term > <constant > io.systemd.Home</constant> </term>
<listitem > <para > This service is provided by
<citerefentry > <refentrytitle > systemd-homed.service</refentrytitle> <manvolnum > 8</manvolnum> </citerefentry>
and makes all users (and their groups) belonging to home directories managed by that service
available to the system.</para> </listitem>
</varlistentry>
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<varlistentry >
<term > <constant > io.systemd.Machine</constant> </term>
<listitem > <para > This service is provided by
<citerefentry > <refentrytitle > systemd-machined.service</refentrytitle> <manvolnum > 8</manvolnum> </citerefentry>
and synthesizes records for all users/groups used by a container that employs user
namespacing.</para> </listitem>
</varlistentry>
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<varlistentry >
<term > <constant > io.systemd.Multiplexer</constant> </term>
<listitem > <para > This service is provided by
<citerefentry > <refentrytitle > systemd-userdbd.service</refentrytitle> <manvolnum > 8</manvolnum> </citerefentry>
and multiplexes user/group look-ups to all other running lookup services. This is the primary entry point
for user/group record clients, as it simplifies client side implementation substantially since they
can ask a single service for lookups instead of asking all running services in parallel.
<command > userdbctl</command> uses this service preferably, too, unless <option > --with-nss=</option>
or <option > --service=</option> are used, in which case finer control over the services to talk to is
required.</para> </listitem>
</varlistentry>
<varlistentry >
<term > <constant > io.systemd.NameSeviceSwitch</constant> </term>
<listitem > <para > This service is (also) provided by
<citerefentry > <refentrytitle > systemd-userdbd.service</refentrytitle> <manvolnum > 8</manvolnum> </citerefentry>
and converts classic NSS/glibc user and group records to JSON user/group records, providing full
backwards compatibility. Use <option > --with-nss=no</option> to disable this compatibility, see
above. Note that compatibility is actually provided in both directions:
<citerefentry > <refentrytitle > nss-systemd</refentrytitle> <manvolnum > 8</manvolnum> </citerefentry> will
automatically synthesize classic NSS/glibc user/group records from all JSON user/group records
provided to the system, thus using both APIs is mostly equivalent and provides access to the same
data, however the NSS/glibc APIs necessarily expose a more reduced set of fields
only.</para> </listitem>
</varlistentry>
</variablelist>
<para > Note that <command > userdbctl</command> has internal support for NSS-based lookups too. This means
that if neither <constant > io.systemd.Multiplexer</constant> nor
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<constant > io.systemd.NameSeviceSwitch</constant> are running look-ups into the basic user/group
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databases will still work.</para>
</refsect1>
<refsect1 >
<title > Integration with SSH</title>
<para > The <command > userdbctl</command> tool may be used to make the list of SSH authorized keys possibly
contained in a user record available to the SSH daemon for authentication. For that configure the
following in <citerefentry
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project='die-net'><refentrytitle > sshd_config</refentrytitle> <manvolnum > 5</manvolnum> </citerefentry> :</para>
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<programlisting > …
AuthorizedKeysCommand /usr/bin/userdbctl ssh-authorized-keys %u
AuthorizedKeysCommandUser root
…</programlisting>
</refsect1>
<refsect1 >
<title > Exit status</title>
<para > On success, 0 is returned, a non-zero failure code otherwise.</para>
</refsect1>
<xi:include href= "less-variables.xml" />
<refsect1 >
<title > See Also</title>
<para >
<citerefentry > <refentrytitle > systemd</refentrytitle> <manvolnum > 1</manvolnum> </citerefentry> ,
<citerefentry > <refentrytitle > systemd-userdbd.service</refentrytitle> <manvolnum > 8</manvolnum> </citerefentry> ,
<citerefentry > <refentrytitle > systemd-homed.service</refentrytitle> <manvolnum > 8</manvolnum> </citerefentry> ,
<citerefentry > <refentrytitle > nss-systemd</refentrytitle> <manvolnum > 8</manvolnum> </citerefentry> ,
<citerefentry project= 'man-pages' > <refentrytitle > getent</refentrytitle> <manvolnum > 1</manvolnum> </citerefentry>
</para>
</refsect1>
</refentry>