1USERDBCTL(1) userdbctl USERDBCTL(1)
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6 userdbctl - Inspect users, groups and group memberships
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9 userdbctl [OPTIONS...] {COMMAND} [NAME...]
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12 userdbctl may be used to inspect user and groups (as well as group
13 memberships) of the system. This client utility inquires user/group
14 information provided by various system services, both operating on JSON
15 user/group records (as defined by the JSON User Record[1] and JSON
16 Group Record[2] definitions), and classic UNIX NSS/glibc user and group
17 records. This tool is primarily a client to the User/Group Record
18 Lookup API via Varlink[3].
19
21 The following options are understood:
22 --output=MODE
24 Choose the output mode, takes one of "classic", "friendly",
25 "table", "json". If "classic", an output very close to the format
26 of /etc/passwd or /etc/group is generated. If "friendly" a more
27 comprehensive and user friendly, human readable output is
28 generated; if "table" a minimal, tabular output is generated; if
29 "json" a JSON formatted output is generated. Defaults to "friendly"
30 if a user/group is specified on the command line, "table"
31 otherwise.
32 --service=SERVICE[:SERVICE...], -s SERVICE:SERVICE...
34 Controls which services to query for users/groups. Takes a list of
35 one or more service names, separated by ":". See below for a list
36 of well-known service names. If not specified all available
37 services are queried at once.
38 --with-nss=BOOL
40 Controls whether to include classic glibc/NSS user/group lookups in
41 the output. If --with-nss=no is used any attempts to resolve or
42 enumerate users/groups provided only via glibc NSS is suppressed.
43 If --with-nss=yes is specified such users/groups are included in
44 the output (which is the default).
45 --synthesize=BOOL
47 Controls whether to synthesize records for the root and nobody
48 users/groups if they aren't defined otherwise. By default (or
49 "yes") such records are implicitly synthesized if otherwise missing
50 since they have special significance to the OS. When "no" this
51 synthesizing is turned off.
52 -N
54 This option is short for --with-nss=no --synthesize=no. Use this
55 option to show only records that are natively defined as JSON user
56 or group records, with all NSS/glibc compatibility and all implicit
57 synthesis turned off.
58 --no-pager
60 Do not pipe output into a pager.
61 --no-legend
63 Do not print the legend, i.e. column headers and the footer with
64 hints.
65 -h, --help
67 Print a short help text and exit.
68 --version
70 Print a short version string and exit.
71
73 The following commands are understood:
74 user [USER...]
76 List all known users records or show details of one or more
77 specified user records. Use --output= to tweak output mode.
78 group [GROUP...]
80 List all known group records or show details of one or more
81 specified group records. Use --output= to tweak output mode.
82 users-in-group [GROUP...]
84 List users that are members of the specified groups. If no groups
85 are specified list all user/group memberships defined. Use
86 --output= to tweak output mode.
87 groups-of-user [USER...]
89 List groups that the specified users are members of. If no users
90 are specified list all user/group memberships defined (in this case
91 groups-of-user and users-in-group are equivalent). Use --output= to
92 tweak output mode.
93 services
95 List all services currently providing user/group definitions to the
96 system. See below for a list of well-known services providing user
97 information.
98 ssh-authorized-keys
100 This operation is not a public, user-facing interface. It is used
101 to allow the SSH daemon to pick up authorized keys from user
102 records, see below.
103
105 The userdbctl services command will list all currently running services
106 that provide user or group definitions to the system. The following
107 well-known services are shown among this list:
108 io.systemd.DynamicUser
110 This service is provided by the system service manager itself (i.e.
111 PID 1) and makes all users (and their groups) synthesized through
112 the DynamicUser= setting in service unit files available to the
113 system (see systemd.exec(5) for details about this setting).
114 io.systemd.Home
116 This service is provided by systemd-homed.service(8) and makes all
117 users (and their groups) belonging to home directories managed by
118 that service available to the system.
119 io.systemd.Machine
121 This service is provided by systemd-machined.service(8) and
122 synthesizes records for all users/groups used by a container that
123 employs user namespacing.
124 io.systemd.Multiplexer
126 This service is provided by systemd-userdbd.service(8) and
127 multiplexes user/group look-ups to all other running lookup
128 services. This is the primary entry point for user/group record
129 clients, as it simplifies client side implementation substantially
130 since they can ask a single service for lookups instead of asking
131 all running services in parallel. userdbctl uses this service
132 preferably, too, unless --with-nss= or --service= are used, in
133 which case finer control over the services to talk to is required.
134 io.systemd.NameSeviceSwitch
136 This service is (also) provided by systemd-userdbd.service(8) and
137 converts classic NSS/glibc user and group records to JSON
138 user/group records, providing full backwards compatibility. Use
139 --with-nss=no to disable this compatibility, see above. Note that
140 compatibility is actually provided in both directions: nss-
141 systemd(8) will automatically synthesize classic NSS/glibc
142 user/group records from all JSON user/group records provided to the
143 system, thus using both APIs is mostly equivalent and provides
144 access to the same data, however the NSS/glibc APIs necessarily
145 expose a more reduced set of fields only.
146 Note that userdbctl has internal support for NSS-based lookups too.
148 This means that if neither io.systemd.Multiplexer nor
149 io.systemd.NameSeviceSwitch are running look-ups into the basic
150 user/group databases will still work.
151
153 The userdbctl tool may be used to make the list of SSH authorized keys
154 possibly contained in a user record available to the SSH daemon for
155 authentication. For that configure the following in sshd_config(5):
156 ...
158 AuthorizedKeysCommand /usr/bin/userdbctl ssh-authorized-keys %u
159 AuthorizedKeysCommandUser root
160 ...
161
163 On success, 0 is returned, a non-zero failure code otherwise.
164
166 $SYSTEMD_PAGER
167 Pager to use when --no-pager is not given; overrides $PAGER. If
168 neither $SYSTEMD_PAGER nor $PAGER are set, a set of well-known
169 pager implementations are tried in turn, including less(1) and
170 more(1), until one is found. If no pager implementation is
171 discovered no pager is invoked. Setting this environment variable
172 to an empty string or the value "cat" is equivalent to passing
173 --no-pager.
174 $SYSTEMD_LESS
176 Override the options passed to less (by default "FRSXMK").
177 Users might want to change two options in particular:
179 K
181 This option instructs the pager to exit immediately when Ctrl+C
182 is pressed. To allow less to handle Ctrl+C itself to switch
183 back to the pager command prompt, unset this option.
184 If the value of $SYSTEMD_LESS does not include "K", and the
186 pager that is invoked is less, Ctrl+C will be ignored by the
187 executable, and needs to be handled by the pager.
188 X
190 This option instructs the pager to not send termcap
191 initialization and deinitialization strings to the terminal. It
192 is set by default to allow command output to remain visible in
193 the terminal even after the pager exits. Nevertheless, this
194 prevents some pager functionality from working, in particular
195 paged output cannot be scrolled with the mouse.
196 See less(1) for more discussion.
198 $SYSTEMD_LESSCHARSET
200 Override the charset passed to less (by default "utf-8", if the
201 invoking terminal is determined to be UTF-8 compatible).
202 $SYSTEMD_PAGERSECURE
204 Takes a boolean argument. When true, the "secure" mode of the pager
205 is enabled; if false, disabled. If $SYSTEMD_PAGERSECURE is not set
206 at all, secure mode is enabled if the effective UID is not the same
207 as the owner of the login session, see geteuid(2) and
208 sd_pid_get_owner_uid(3). In secure mode, LESSSECURE=1 will be set
209 when invoking the pager, and the pager shall disable commands that
210 open or create new files or start new subprocesses. When
211 $SYSTEMD_PAGERSECURE is not set at all, pagers which are not known
212 to implement secure mode will not be used. (Currently only less(1)
213 implements secure mode.)
214 Note: when commands are invoked with elevated privileges, for
216 example under sudo(8) or pkexec(1), care must be taken to ensure
217 that unintended interactive features are not enabled. "Secure" mode
218 for the pager may be enabled automatically as describe above.
219 Setting SYSTEMD_PAGERSECURE=0 or not removing it from the inherited
220 environment allows the user to invoke arbitrary commands. Note that
221 if the $SYSTEMD_PAGER or $PAGER variables are to be honoured,
222 $SYSTEMD_PAGERSECURE must be set too. It might be reasonable to
223 completly disable the pager using --no-pager instead.
224 $SYSTEMD_COLORS
226 The value must be a boolean. Controls whether colorized output
227 should be generated. This can be specified to override the decision
228 that systemd makes based on $TERM and what the console is connected
229 to.
230 $SYSTEMD_URLIFY
232 The value must be a boolean. Controls whether clickable links
233 should be generated in the output for terminal emulators supporting
234 this. This can be specified to override the decision that systemd
235 makes based on $TERM and other conditions.
236
238 systemd(1), systemd-userdbd.service(8), systemd-homed.service(8), nss-
239 systemd(8), getent(1)
240
242 1. JSON User Record
243 https://systemd.io/USER_RECORD
244 2. JSON Group Record
246 https://systemd.io/GROUP_RECORD
247 3. User/Group Record Lookup API via Varlink
249 https://systemd.io/USER_GROUP_API
250systemd 246 USERDBCTL(1)