# userdbctl

## NAME



           userdbctl - Inspect users, groups and group memberships
    


## SYNOPSIS



    
           **userdbctl**[OPTIONS...] {COMMAND} [NAME...]
    


## DESCRIPTION



           **userdbctl** 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 **JSON User**
           **Records******[1] and**JSON Group Records******[2] definitions), and classic
           UNIX NSS/glibc user and group records. This tool is primarily a
           client to the**User/Group Record Lookup API via Varlink******[3], and may
           also pick up drop-in JSON user and group records from
           /etc/userdb/, /run/userdb/, /run/host/userdb/, /usr/lib/userdb/
           (seenss-systemd(8) for details about drop-in user records).
    


## OPTIONS



           The following options are understood:
    
           **--output=**_MODE_
               Chooses the output mode. Takes one of "classic", "friendly",
               "table" or "json". If "classic", an output very close to the
               format of /etc/passwd or /etc/group is generated. If
               "friendly", a more comprehensive and user friendly,
               human-readable output is generated. If "table", a minimal,
               tabular output is generated. If "json", a JSON formatted
               output is generated. Defaults to "friendly" if a user/group is
               specified on the command line, "table" otherwise.
    
               Note that most output formats do not show all available
               information. In particular, "classic" and "table" show only
               the most important fields. Various modes also do not show
               password hashes. Use "json" to view all fields, including any
               authentication fields.
    
               Added in version 245.
    
           **--json=**_FORMAT_
               Selects JSON output mode (like **--output=json**) and selects the
               precise display mode. Takes one of "pretty" or "short". If
               "pretty", human-friendly whitespace and newlines are inserted
               in the output to make the JSON data more readable. If "short",
               all superfluous whitespace is suppressed.
    
               Added in version 250.
    
           **--service=**_SERVICE_**[:**_SERVICE..._], **-s** _SERVICE_ :_SERVICE..._
               Controls which services to query for users/groups. Takes a
               list of one or more service names, separated by ":". See below
               for a list of well-known service names. If not specified, all
               available services are queried at once.
    
               Added in version 245.
    
           **--with-nss=**_BOOL_
               Controls whether to include classic glibc/NSS user/group
               lookups in the output. If **--with-nss=no** is used, any attempts
               to resolve or enumerate users/groups provided only via glibc
               NSS is suppressed. If **--with-nss=yes** is specified, such
               users/groups are included in the output (which is the
               default).
    
               Added in version 245.
    
           **--with-varlink=**_BOOL_
               Controls whether to include Varlink user/group lookups in the
               output, i.e. those done via the **User/Group Record Lookup API**
               **via Varlink******[3]. If**--with-varlink=no** is used, any attempts to
               resolve or enumerate users/groups provided only via Varlink
               are suppressed. If **--with-varlink=yes** is specified, such
               users/groups are included in the output (which is the
               default).
    
               Added in version 249.
    
           **--with-dropin=**_BOOL_
               Controls whether to include user/group lookups in the output
               that are defined using drop-in files in /etc/userdb/,
               /run/userdb/, /run/host/userdb/, /usr/lib/userdb/. If
               **--with-dropin=no** is used, these records are suppressed. If
               **--with-dropin=yes** is specified, such users/groups are included
               in the output (which is the default).
    
               Added in version 249.
    
           **--synthesize=**_BOOL_
               Controls whether to synthesize records for the root and nobody
               users/groups if they are not defined otherwise, as well as the
               user/groups for the "foreign" UID range. By default (or with
               "yes"), such records are implicitly synthesized if otherwise
               missing since they have special significance to the OS. When
               "no", this synthesizing is turned off.
    
               Added in version 245.
    
           **-N**
               This option is short for **--with-nss=no --synthesize=no**. 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.
    
               Added in version 245.
    
           **--multiplexer=**_BOOL_
               Controls whether to do lookups via the multiplexer service (if
               specified as true, the default) or do lookups in the client
               (if specified as false). Using the multiplexer service is
               typically preferable, since it runs in a locked down sandbox.
    
               Added in version 250.
    
           **--chain**
               When used with the **ssh-authorized-keys** command, this will
               allow passing an additional command line after the user name
               that is chain executed after the lookup completed. This allows
               chaining multiple tools that show SSH authorized keys.
    
               Added in version 250.
    
           **--fuzzy** , **-z**
               When used with the **user** or **group** command, do a fuzzy string
               search. Any specified arguments will be matched against the
               user name, the real name of the user record, the email
               address, and other descriptive strings of the user or group
               record. Moreover, instead of precise matching, a substring
               match or a match allowing slight deviations in spelling is
               applied.
    
               Added in version 257.
    
           **--disposition=**
               When used with the **user** or **group** command, filters by
               disposition of the record. Takes one of "intrinsic", "system",
               "regular", "dynamic", "container". May be used multiple times,
               in which case only users matching any of the specified
               dispositions are shown.
    
               Added in version 257.
    
           **-I** , **-S** , **-R**
               Shortcuts for **--disposition=intrinsic** , **--disposition=system** ,
               **--disposition=regular** , respectively.
    
               Added in version 257.
    
           **--uid-min=** , **--uid-max=**
               When used with the **user** or **group** command, filters the output
               by UID/GID ranges. Takes numeric minimum or maximum UID/GID
               values, respectively. Shows only records within the specified
               range. When applied to the **user** command, it matches against
               UIDs. When applied to the **group** command, matches against GIDs
               (despite the name of the switch). If unspecified, defaults to
               0 (for the minimum) and 4294967294 (for the maximum), i.e. by
               default, no filtering is applied, as the whole UID/GID range
               is covered.
    
               Added in version 257.
    
           **--boundaries=**
               When used with the **user** or **group** command, controls whether to
               show relevant UID/GID range boundary information in the
               tabular output. Takes a boolean. Defaults to true.
    
               Added in version 257.
    
           **-B**
               Shortcut for **--boundaries=no**.
    
               Added in version 257.
    
           **--from-file=PATH** , **-f**
               When used with the **user** or **group** command, read the user
               definition in JSON format from the specified file, instead of
               querying it from the system. If the path is specified as "-",
               reads the JSON data from standard input. This is useful to
               validate and introspect JSON user or group records quickly,
               and check how they would be interpreted on the local system.
    
               Added in version 258.
    
           **--no-pager**
               Do not pipe output into a pager.
    
           **--no-legend**
               Do not print the legend, i.e. column headers and the footer
               with hints.
    
           **-h** , **--help**
               Print a short help text and exit.
    
           **--version**
               Print a short version string and exit.
    


## COMMANDS



           The following commands are understood:
    
           **user**[_USER_...]
               List all known users records or show details of one or more
               specified user records. Use **--output=** to tweak output mode.
    
               If used in conjunction with **--from-file=** the user record data
               is read in JSON format from the specified file instead of
               querying it from the system. For details see above.
    
               Added in version 245.
    
           **group**[_GROUP_...]
               List all known group records or show details of one or more
               specified group records. Use **--output=** to tweak the output
               mode.
    
               If used in conjunction with **--from-file=** the group record data
               is read in JSON format from the specified file instead of
               querying it from the system. For details see above.
    
               Added in version 245.
    
           **users-in-group**[_GROUP_...]
               List users that are members of the specified groups. If no
               groups are specified, list all user/group memberships defined.
               Use **--output=** to tweak the output mode.
    
               Added in version 245.
    
           **groups-of-user**[_USER_...]
               Lists groups that the specified users are members of. If no
               users are specified, lists all user/group memberships defined
               (in this case, **groups-of-user** and **users-in-group** are
               equivalent). Use **--output=** to tweak the output mode.
    
               Added in version 245.
    
           **services**
               List all services currently providing user/group definitions
               to the system. See below for a list of well-known services
               providing user information.
    
               Added in version 245.
    
           **ssh-authorized-keys**
               Show SSH authorized keys for this account. This command is
               intended to be used to allow the SSH daemon to pick up
               authorized keys from user records, see below.
    
               Added in version 245.
    
           **load-credentials**
               When specified, the following credentials are used when passed
               in:
    
               _userdb.user.*_ , _userdb.group.*_
                   These credentials should contain valid **JSON User******[1] and**JSON Group******[2] records. For each matching credential,
                   various files are created in /etc/userdb/, implementing
                   the interface described innss-systemd(8). Any passed user
                   records must contain valid UID and GID fields. Any passed
                   group records must contain a GID field (i.e. automatic
                   UID/GID allocation is not supported). For both user and
                   group records, the credential suffix (for
                   "userdb.user.foobar" the suffix is "foobar") must match
                   the user or group name encoded in the record.
    
                   Added in version 258.
    
               Added in version 258.
    


## WELL-KNOWN SERVICES



           The **userdbctl services** command will list all currently running
           services that provide user or group definitions to the system. The
           following well-known services are shown among this list:
    
           **io.systemd.DynamicUser**
               This service is provided by the system service manager itself
               (i.e. PID 1) and makes all users (and their groups)
               synthesized through the _DynamicUser=_ setting in service unit
               files available to the system (see systemd.exec(5) for details
               about this setting).
    
               Added in version 245.
    
           **io.systemd.Home**
               This service is provided by systemd-homed.service(8) and makes
               all users (and their groups) belonging to home directories
               managed by that service available to the system.
    
               Added in version 245.
    
           **io.systemd.Machine**
               This service is provided by systemd-machined.service(8) and
               synthesizes records for all users/groups used by a container
               that employs user namespacing.
    
               Added in version 246.
    
           **io.systemd.Multiplexer**
               This service is provided by systemd-userdbd.service(8) 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.  **userdbctl**
               uses this service preferably, too, unless **--with-nss=** or
               **--service=** are used, in which case finer control over the
               services to talk to is required.
    
               Added in version 245.
    
           **io.systemd.NameServiceSwitch**
               This service is (also) provided by systemd-userdbd.service(8)
               and converts classic NSS/glibc user and group records to JSON
               user/group records, providing full backwards compatibility.
               Use **--with-nss=no** to disable this compatibility, see above.
               Note that compatibility is actually provided in both
               directions: nss-systemd(8) 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.
    
               Added in version 245.
    
           **io.systemd.DropIn**
               This service is (also) provided by systemd-userdbd.service(8)
               and picks up JSON user/group records from /etc/userdb/,
               /run/userdb/, /run/host/userdb/, /usr/lib/userdb/.
    
               Added in version 249.
    
           Note that **userdbctl** has internal support for NSS-based lookups
           too. This means that if neither **io.systemd.Multiplexer** nor
           **io.systemd.NameServiceSwitch** are running, look-ups into the basic
           user/group databases will still work.
    


## INTEGRATION WITH SSH



           The **userdbctl** 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
           sshd_config(5):
    
               ...
               AuthorizedKeysCommand /usr/bin/userdbctl ssh-authorized-keys %u
               AuthorizedKeysCommandUser root
               ...
    
           Sometimes, it is useful to allow chain invocation of another
           program to list SSH authorized keys. By using the **--chain** option,
           such a tool may be chain executed by **userdbctl ssh-authorized-keys**
           once a lookup completes, regardless of whether an SSH key was
           found or not. Example:
    
               ...
               AuthorizedKeysCommand /usr/bin/userdbctl ssh-authorized-keys %u --chain /usr/bin/othertool %u
               AuthorizedKeysCommandUser root
               ...
    
           The above will first query the userdb database for SSH keys, and
           then chain execute **/usr/bin/othertool** to also be queried.
    


## EXIT STATUS



           On success, 0 is returned, and a non-zero failure code otherwise.
    


## ENVIRONMENT



           _$SYSTEMD_LOG_LEVEL_
               The maximum log level of emitted messages (messages with a
               higher log level, i.e. less important ones, will be
               suppressed). Takes a comma-separated list of values. A value
               may be either one of (in order of decreasing importance)
               **emerg** , **alert** , **crit** , **err** , **warning** , **notice** , **info** , **debug** , or an
               integer in the range 0...7. See syslog(3) for more
               information. Each value may optionally be prefixed with one of
               **console** , **syslog** , **kmsg** or **journal** followed by a colon to set
               the maximum log level for that specific log target (e.g.
               **SYSTEMD_LOG_LEVEL=debug,console:info** specifies to log at debug
               level except when logging to the console which should be at
               info level). Note that the global maximum log level takes
               priority over any per target maximum log levels.
    
           _$SYSTEMD_LOG_COLOR_
               A boolean. If true, messages written to the tty will be
               colored according to priority.
    
               This setting is only useful when messages are written directly
               to the terminal, because journalctl(1) and other tools that
               display logs will color messages based on the log level on
               their own.
    
           _$SYSTEMD_LOG_TIME_
               A boolean. If true, console log messages will be prefixed with
               a timestamp.
    
               This setting is only useful when messages are written directly
               to the terminal or a file, because journalctl(1) and other
               tools that display logs will attach timestamps based on the
               entry metadata on their own.
    
           _$SYSTEMD_LOG_LOCATION_
               A boolean. If true, messages will be prefixed with a filename
               and line number in the source code where the message
               originates.
    
               Note that the log location is often attached as metadata to
               journal entries anyway. Including it directly in the message
               text can nevertheless be convenient when debugging programs.
    
           _$SYSTEMD_LOG_TID_
               A boolean. If true, messages will be prefixed with the current
               numerical thread ID (TID).
    
               Note that the this information is attached as metadata to
               journal entries anyway. Including it directly in the message
               text can nevertheless be convenient when debugging programs.
    
           _$SYSTEMD_LOG_TARGET_
               The destination for log messages. One of **console**(log to the
               attached tty), **console-prefixed**(log to the attached tty but
               with prefixes encoding the log level and "facility", see
               syslog(3), **kmsg**(log to the kernel circular log buffer),
               **journal**(log to the journal), **journal-or-kmsg**(log to the
               journal if available, and to kmsg otherwise), **auto**(determine
               the appropriate log target automatically, the default), **null**
               (disable log output).
    
           _$SYSTEMD_LOG_RATELIMIT_KMSG_
               Whether to ratelimit kmsg or not. Takes a boolean. Defaults to
               "true". If disabled, systemd will not ratelimit messages
               written to kmsg.
    
           _$SYSTEMD_PAGER_ , _$PAGER_
               Pager to use when **--no-pager** is not given.  _$SYSTEMD_PAGER_ is
               used if set; otherwise _$PAGER_ is used. If neither
               _$SYSTEMD_PAGER_ nor _$PAGER_ are set, a set of well-known pager
               implementations is tried in turn, including less(1) and
               more(1), until one is found. If no pager implementation is
               discovered, no pager is invoked. Setting those environment
               variables to an empty string or the value "cat" is equivalent
               to passing **--no-pager**.
    
               Note: if _$SYSTEMD_PAGERSECURE_ is not set, _$SYSTEMD_PAGER_ and
               _$PAGER_ can only be used to disable the pager (with "cat" or
               ""), and are otherwise ignored.
    
           _$SYSTEMD_LESS_
               Override the options passed to **less**(by default "FRSXMK").
    
               Users might want to change two options in particular:
    
               **K**
                   This option instructs the pager to exit immediately when
                   Ctrl+C is pressed. To allow **less** to handle Ctrl+C itself
                   to switch back to the pager command prompt, unset this
                   option.
    
                   If the value of _$SYSTEMD_LESS_ does not include "K", and
                   the pager that is invoked is **less** , Ctrl+C will be ignored
                   by the executable, and needs to be handled by the pager.
    
               **X**
                   This option instructs the pager to not send termcap
                   initialization and deinitialization strings to the
                   terminal. It is set by default to allow command output to
                   remain visible in the terminal even after the pager exits.
                   Nevertheless, this prevents some pager functionality from
                   working, in particular paged output cannot be scrolled
                   with the mouse.
    
               Note that setting the regular _$LESS_ environment variable has
               no effect for **less** invocations by systemd tools.
    
               See less(1) for more discussion.
    
           _$SYSTEMD_LESSCHARSET_
               Override the charset passed to **less**(by default "utf-8", if
               the invoking terminal is determined to be UTF-8 compatible).
    
               Note that setting the regular _$LESSCHARSET_ environment
               variable has no effect for **less** invocations by systemd tools.
    
           _$SYSTEMD_PAGERSECURE_
               Common pager commands like less(1), in addition to "paging",
               i.e. scrolling through the output, support opening of or
               writing to other files and running arbitrary shell commands.
               When commands are invoked with elevated privileges, for
               example under sudo(8) or **pkexec**(1), the pager becomes a
               security boundary. Care must be taken that only programs with
               strictly limited functionality are used as pagers, and
               unintended interactive features like opening or creation of
               new files or starting of subprocesses are not allowed. "Secure
               mode" for the pager may be enabled as described below, _if the_
               _pager supports that_ (most pagers are not written in a way that
               takes this into consideration). It is recommended to either
               explicitly enable "secure mode" or to completely disable the
               pager using **--no-pager** or _PAGER=cat_ when allowing untrusted
               users to execute commands with elevated privileges.
    
               This option takes a boolean argument. When set to true, the
               "secure mode" of the pager is enabled. In "secure mode",
               **LESSSECURE=1** will be set when invoking the pager, which
               instructs the pager to disable commands that open or create
               new files or start new subprocesses. Currently only less(1) is
               known to understand this variable and implement "secure mode".
    
               When set to false, no limitation is placed on the pager.
               Setting _SYSTEMD_PAGERSECURE=0_ or not removing it from the
               inherited environment may allow the user to invoke arbitrary
               commands.
    
               When _$SYSTEMD_PAGERSECURE_ is not set, systemd tools attempt to
               automatically figure out if "secure mode" should be enabled
               and whether the pager supports it. "Secure mode" is enabled if
               the effective UID is not the same as the owner of the login
               session, see geteuid(2) and sd_pid_get_owner_uid(3), or when
               running under sudo(8) or similar tools (_$SUDO_UID_ is set [4]).
               In those cases, _SYSTEMD_PAGERSECURE=1_ will be set and pagers
               which are not known to implement "secure mode" will not be
               used at all. Note that this autodetection only covers the most
               common mechanisms to elevate privileges and is intended as
               convenience. It is recommended to explicitly set
               _$SYSTEMD_PAGERSECURE_ or disable the pager.
    
               Note that if the _$SYSTEMD_PAGER_ or _$PAGER_ variables are to be
               honoured, other than to disable the pager,
               _$SYSTEMD_PAGERSECURE_ must be set too.
    
           _$SYSTEMD_COLORS_
               Takes a boolean argument. When true, **systemd** and related
               utilities will use colors in their output, otherwise the
               output will be monochrome. Additionally, the variable can take
               one of the following special values: "16", "256" to restrict
               the use of colors to the base 16 or 256 ANSI colors,
               respectively. This can be specified to override the automatic
               decision based on _$TERM_ and what the console is connected to.
    
           _$SYSTEMD_URLIFY_
               The value must be a boolean. Controls whether clickable links
               should be generated in the output for terminal emulators
               supporting this. This can be specified to override the
               decision that **systemd** makes based on _$TERM_ and other
               conditions.
    


## NOTES



            1. JSON User Records
               https://systemd.io/USER_RECORD
    
            2. JSON Group Records
               https://systemd.io/GROUP_RECORD
    
            3. User/Group Record Lookup API via Varlink
               https://systemd.io/USER_GROUP_API
    
            4. It is recommended for other tools to set and check _$SUDO_UID_
               as appropriate, treating it is a common interface.
    


* * *