1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
|
'\" t
.TH "USERDBCTL" "1" "" "systemd 255" "userdbctl"
.\" -----------------------------------------------------------------
.\" * Define some portability stuff
.\" -----------------------------------------------------------------
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.\" http://bugs.debian.org/507673
.\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html
.\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
.ie \n(.g .ds Aq \(aq
.el .ds Aq '
.\" -----------------------------------------------------------------
.\" * set default formatting
.\" -----------------------------------------------------------------
.\" disable hyphenation
.nh
.\" disable justification (adjust text to left margin only)
.ad l
.\" -----------------------------------------------------------------
.\" * MAIN CONTENT STARTS HERE *
.\" -----------------------------------------------------------------
.SH "NAME"
userdbctl \- Inspect users, groups and group memberships
.SH "SYNOPSIS"
.HP \w'\fBuserdbctl\fR\ 'u
\fBuserdbctl\fR [OPTIONS...] {COMMAND} [NAME...]
.SH "DESCRIPTION"
.PP
\fBuserdbctl\fR
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
\m[blue]\fBJSON User Records\fR\m[]\&\s-2\u[1]\d\s+2
and
\m[blue]\fBJSON Group Records\fR\m[]\&\s-2\u[2]\d\s+2
definitions), and classic UNIX NSS/glibc user and group records\&. This tool is primarily a client to the
\m[blue]\fBUser/Group Record Lookup API via Varlink\fR\m[]\&\s-2\u[3]\d\s+2, and may also pick up drop\-in JSON user and group records from
/etc/userdb/,
/run/userdb/,
/run/host/userdb/,
/usr/lib/userdb/\&.
.SH "OPTIONS"
.PP
The following options are understood:
.PP
\fB\-\-output=\fR\fIMODE\fR
.RS 4
Choose the output mode, takes one of
"classic",
"friendly",
"table",
"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\&.
.sp
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\&.
.sp
Added in version 245\&.
.RE
.PP
\fB\-\-json=\fR\fIFORMAT\fR
.RS 4
Selects JSON output mode (like
\fB\-\-output=json\fR) 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\&.
.sp
Added in version 250\&.
.RE
.PP
\fB\-\-service=\fR\fISERVICE\fR[:\fISERVICE\&...\fR], \fB\-s\fR \fISERVICE\fR:\fISERVICE\&...\fR
.RS 4
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\&.
.sp
Added in version 245\&.
.RE
.PP
\fB\-\-with\-nss=\fR\fIBOOL\fR
.RS 4
Controls whether to include classic glibc/NSS user/group lookups in the output\&. If
\fB\-\-with\-nss=no\fR
is used any attempts to resolve or enumerate users/groups provided only via glibc NSS is suppressed\&. If
\fB\-\-with\-nss=yes\fR
is specified such users/groups are included in the output (which is the default)\&.
.sp
Added in version 245\&.
.RE
.PP
\fB\-\-with\-varlink=\fR\fIBOOL\fR
.RS 4
Controls whether to include Varlink user/group lookups in the output, i\&.e\&. those done via the
\m[blue]\fBUser/Group Record Lookup API via Varlink\fR\m[]\&\s-2\u[3]\d\s+2\&. If
\fB\-\-with\-varlink=no\fR
is used any attempts to resolve or enumerate users/groups provided only via Varlink are suppressed\&. If
\fB\-\-with\-varlink=yes\fR
is specified such users/groups are included in the output (which is the default)\&.
.sp
Added in version 249\&.
.RE
.PP
\fB\-\-with\-dropin=\fR\fIBOOL\fR
.RS 4
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
\fB\-\-with\-dropin=no\fR
is used these records are suppressed\&. If
\fB\-\-with\-dropin=yes\fR
is specified such users/groups are included in the output (which is the default)\&.
.sp
Added in version 249\&.
.RE
.PP
\fB\-\-synthesize=\fR\fIBOOL\fR
.RS 4
Controls whether to synthesize records for the root and nobody users/groups if they aren\*(Aqt defined otherwise\&. By default (or
"yes") such records are implicitly synthesized if otherwise missing since they have special significance to the OS\&. When
"no"
this synthesizing is turned off\&.
.sp
Added in version 245\&.
.RE
.PP
\fB\-N\fR
.RS 4
This option is short for
\fB\-\-with\-nss=no\fR
\fB\-\-synthesize=no\fR\&. 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\&.
.sp
Added in version 245\&.
.RE
.PP
\fB\-\-multiplexer=\fR\fIBOOL\fR
.RS 4
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\&.
.sp
Added in version 250\&.
.RE
.PP
\fB\-\-chain\fR
.RS 4
When used with the
\fBssh\-authorized\-keys\fR
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\&.
.sp
Added in version 250\&.
.RE
.PP
\fB\-\-no\-pager\fR
.RS 4
Do not pipe output into a pager\&.
.RE
.PP
\fB\-\-no\-legend\fR
.RS 4
Do not print the legend, i\&.e\&. column headers and the footer with hints\&.
.RE
.PP
\fB\-h\fR, \fB\-\-help\fR
.RS 4
Print a short help text and exit\&.
.RE
.PP
\fB\-\-version\fR
.RS 4
Print a short version string and exit\&.
.RE
.SH "COMMANDS"
.PP
The following commands are understood:
.PP
\fBuser\fR [\fIUSER\fR\&...]
.RS 4
List all known users records or show details of one or more specified user records\&. Use
\fB\-\-output=\fR
to tweak output mode\&.
.sp
Added in version 245\&.
.RE
.PP
\fBgroup\fR [\fIGROUP\fR\&...]
.RS 4
List all known group records or show details of one or more specified group records\&. Use
\fB\-\-output=\fR
to tweak output mode\&.
.sp
Added in version 245\&.
.RE
.PP
\fBusers\-in\-group\fR [\fIGROUP\fR\&...]
.RS 4
List users that are members of the specified groups\&. If no groups are specified list all user/group memberships defined\&. Use
\fB\-\-output=\fR
to tweak output mode\&.
.sp
Added in version 245\&.
.RE
.PP
\fBgroups\-of\-user\fR [\fIUSER\fR\&...]
.RS 4
List groups that the specified users are members of\&. If no users are specified list all user/group memberships defined (in this case
\fBgroups\-of\-user\fR
and
\fBusers\-in\-group\fR
are equivalent)\&. Use
\fB\-\-output=\fR
to tweak output mode\&.
.sp
Added in version 245\&.
.RE
.PP
\fBservices\fR
.RS 4
List all services currently providing user/group definitions to the system\&. See below for a list of well\-known services providing user information\&.
.sp
Added in version 245\&.
.RE
.PP
\fBssh\-authorized\-keys\fR
.RS 4
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\&.
.sp
Added in version 245\&.
.RE
.SH "WELL\-KNOWN SERVICES"
.PP
The
\fBuserdbctl services\fR
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:
.PP
\fBio\&.systemd\&.DynamicUser\fR
.RS 4
This service is provided by the system service manager itself (i\&.e\&. PID 1) and makes all users (and their groups) synthesized through the
\fIDynamicUser=\fR
setting in service unit files available to the system (see
\fBsystemd.exec\fR(5)
for details about this setting)\&.
.sp
Added in version 245\&.
.RE
.PP
\fBio\&.systemd\&.Home\fR
.RS 4
This service is provided by
\fBsystemd-homed.service\fR(8)
and makes all users (and their groups) belonging to home directories managed by that service available to the system\&.
.sp
Added in version 245\&.
.RE
.PP
\fBio\&.systemd\&.Machine\fR
.RS 4
This service is provided by
\fBsystemd-machined.service\fR(8)
and synthesizes records for all users/groups used by a container that employs user namespacing\&.
.sp
Added in version 246\&.
.RE
.PP
\fBio\&.systemd\&.Multiplexer\fR
.RS 4
This service is provided by
\fBsystemd-userdbd.service\fR(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\&.
\fBuserdbctl\fR
uses this service preferably, too, unless
\fB\-\-with\-nss=\fR
or
\fB\-\-service=\fR
are used, in which case finer control over the services to talk to is required\&.
.sp
Added in version 245\&.
.RE
.PP
\fBio\&.systemd\&.NameServiceSwitch\fR
.RS 4
This service is (also) provided by
\fBsystemd-userdbd.service\fR(8)
and converts classic NSS/glibc user and group records to JSON user/group records, providing full backwards compatibility\&. Use
\fB\-\-with\-nss=no\fR
to disable this compatibility, see above\&. Note that compatibility is actually provided in both directions:
\fBnss-systemd\fR(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\&.
.sp
Added in version 245\&.
.RE
.PP
\fBio\&.systemd\&.DropIn\fR
.RS 4
This service is (also) provided by
\fBsystemd-userdbd.service\fR(8)
and picks up JSON user/group records from
/etc/userdb/,
/run/userdb/,
/run/host/userdb/,
/usr/lib/userdb/\&.
.sp
Added in version 249\&.
.RE
.PP
Note that
\fBuserdbctl\fR
has internal support for NSS\-based lookups too\&. This means that if neither
\fBio\&.systemd\&.Multiplexer\fR
nor
\fBio\&.systemd\&.NameServiceSwitch\fR
are running look\-ups into the basic user/group databases will still work\&.
.SH "INTEGRATION WITH SSH"
.PP
The
\fBuserdbctl\fR
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
\fBsshd_config\fR(5):
.sp
.if n \{\
.RS 4
.\}
.nf
\&...
AuthorizedKeysCommand /usr/bin/userdbctl ssh\-authorized\-keys %u
AuthorizedKeysCommandUser root
\&...
.fi
.if n \{\
.RE
.\}
.PP
Sometimes it\*(Aqs useful to allow chain invocation of another program to list SSH authorized keys\&. By using the
\fB\-\-chain\fR
such a tool may be chain executed by
\fBuserdbctl ssh\-authorized\-keys\fR
once a lookup completes (regardless if an SSH key was found or not)\&. Example:
.sp
.if n \{\
.RS 4
.\}
.nf
\&...
AuthorizedKeysCommand /usr/bin/userdbctl ssh\-authorized\-keys %u \-\-chain /usr/bin/othertool %u
AuthorizedKeysCommandUser root
\&...
.fi
.if n \{\
.RE
.\}
.PP
The above will first query the userdb database for SSH keys, and then chain execute
\fB/usr/bin/othertool\fR
to also be queried\&.
.SH "EXIT STATUS"
.PP
On success, 0 is returned, a non\-zero failure code otherwise\&.
.SH "ENVIRONMENT"
.PP
\fI$SYSTEMD_LOG_LEVEL\fR
.RS 4
The maximum log level of emitted messages (messages with a higher log level, i\&.e\&. less important ones, will be suppressed)\&. Either one of (in order of decreasing importance)
\fBemerg\fR,
\fBalert\fR,
\fBcrit\fR,
\fBerr\fR,
\fBwarning\fR,
\fBnotice\fR,
\fBinfo\fR,
\fBdebug\fR, or an integer in the range 0\&...7\&. See
\fBsyslog\fR(3)
for more information\&.
.RE
.PP
\fI$SYSTEMD_LOG_COLOR\fR
.RS 4
A boolean\&. If true, messages written to the tty will be colored according to priority\&.
.sp
This setting is only useful when messages are written directly to the terminal, because
\fBjournalctl\fR(1)
and other tools that display logs will color messages based on the log level on their own\&.
.RE
.PP
\fI$SYSTEMD_LOG_TIME\fR
.RS 4
A boolean\&. If true, console log messages will be prefixed with a timestamp\&.
.sp
This setting is only useful when messages are written directly to the terminal or a file, because
\fBjournalctl\fR(1)
and other tools that display logs will attach timestamps based on the entry metadata on their own\&.
.RE
.PP
\fI$SYSTEMD_LOG_LOCATION\fR
.RS 4
A boolean\&. If true, messages will be prefixed with a filename and line number in the source code where the message originates\&.
.sp
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\&.
.RE
.PP
\fI$SYSTEMD_LOG_TID\fR
.RS 4
A boolean\&. If true, messages will be prefixed with the current numerical thread ID (TID)\&.
.sp
Note that the this information is attached as metadata to journal entries anyway\&. Including it directly in the message text can nevertheless be convenient when debugging programs\&.
.RE
.PP
\fI$SYSTEMD_LOG_TARGET\fR
.RS 4
The destination for log messages\&. One of
\fBconsole\fR
(log to the attached tty),
\fBconsole\-prefixed\fR
(log to the attached tty but with prefixes encoding the log level and "facility", see
\fBsyslog\fR(3),
\fBkmsg\fR
(log to the kernel circular log buffer),
\fBjournal\fR
(log to the journal),
\fBjournal\-or\-kmsg\fR
(log to the journal if available, and to kmsg otherwise),
\fBauto\fR
(determine the appropriate log target automatically, the default),
\fBnull\fR
(disable log output)\&.
.RE
.PP
\fI$SYSTEMD_LOG_RATELIMIT_KMSG\fR
.RS 4
Whether to ratelimit kmsg or not\&. Takes a boolean\&. Defaults to
"true"\&. If disabled, systemd will not ratelimit messages written to kmsg\&.
.RE
.PP
\fI$SYSTEMD_PAGER\fR
.RS 4
Pager to use when
\fB\-\-no\-pager\fR
is not given; overrides
\fI$PAGER\fR\&. If neither
\fI$SYSTEMD_PAGER\fR
nor
\fI$PAGER\fR
are set, a set of well\-known pager implementations are tried in turn, including
\fBless\fR(1)
and
\fBmore\fR(1), until one is found\&. If no pager implementation is discovered no pager is invoked\&. Setting this environment variable to an empty string or the value
"cat"
is equivalent to passing
\fB\-\-no\-pager\fR\&.
.sp
Note: if
\fI$SYSTEMD_PAGERSECURE\fR
is not set,
\fI$SYSTEMD_PAGER\fR
(as well as
\fI$PAGER\fR) will be silently ignored\&.
.RE
.PP
\fI$SYSTEMD_LESS\fR
.RS 4
Override the options passed to
\fBless\fR
(by default
"FRSXMK")\&.
.sp
Users might want to change two options in particular:
.PP
\fBK\fR
.RS 4
This option instructs the pager to exit immediately when
Ctrl+C
is pressed\&. To allow
\fBless\fR
to handle
Ctrl+C
itself to switch back to the pager command prompt, unset this option\&.
.sp
If the value of
\fI$SYSTEMD_LESS\fR
does not include
"K", and the pager that is invoked is
\fBless\fR,
Ctrl+C
will be ignored by the executable, and needs to be handled by the pager\&.
.RE
.PP
\fBX\fR
.RS 4
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\&.
.RE
.sp
See
\fBless\fR(1)
for more discussion\&.
.RE
.PP
\fI$SYSTEMD_LESSCHARSET\fR
.RS 4
Override the charset passed to
\fBless\fR
(by default
"utf\-8", if the invoking terminal is determined to be UTF\-8 compatible)\&.
.RE
.PP
\fI$SYSTEMD_PAGERSECURE\fR
.RS 4
Takes a boolean argument\&. When true, the "secure" mode of the pager is enabled; if false, disabled\&. If
\fI$SYSTEMD_PAGERSECURE\fR
is not set at all, secure mode is enabled if the effective UID is not the same as the owner of the login session, see
\fBgeteuid\fR(2)
and
\fBsd_pid_get_owner_uid\fR(3)\&. In secure mode,
\fBLESSSECURE=1\fR
will be set when invoking the pager, and the pager shall disable commands that open or create new files or start new subprocesses\&. When
\fI$SYSTEMD_PAGERSECURE\fR
is not set at all, pagers which are not known to implement secure mode will not be used\&. (Currently only
\fBless\fR(1)
implements secure mode\&.)
.sp
Note: when commands are invoked with elevated privileges, for example under
\fBsudo\fR(8)
or
\fBpkexec\fR(1), care must be taken to ensure that unintended interactive features are not enabled\&. "Secure" mode for the pager may be enabled automatically as describe above\&. Setting
\fISYSTEMD_PAGERSECURE=0\fR
or not removing it from the inherited environment allows the user to invoke arbitrary commands\&. Note that if the
\fI$SYSTEMD_PAGER\fR
or
\fI$PAGER\fR
variables are to be honoured,
\fI$SYSTEMD_PAGERSECURE\fR
must be set too\&. It might be reasonable to completely disable the pager using
\fB\-\-no\-pager\fR
instead\&.
.RE
.PP
\fI$SYSTEMD_COLORS\fR
.RS 4
Takes a boolean argument\&. When true,
\fBsystemd\fR
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
\fI$TERM\fR
and what the console is connected to\&.
.RE
.PP
\fI$SYSTEMD_URLIFY\fR
.RS 4
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
\fBsystemd\fR
makes based on
\fI$TERM\fR
and other conditions\&.
.RE
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1),
\fBsystemd-userdbd.service\fR(8),
\fBsystemd-homed.service\fR(8),
\fBnss-systemd\fR(8),
\fBgetent\fR(1)
.SH "NOTES"
.IP " 1." 4
JSON User Records
.RS 4
\%https://systemd.io/USER_RECORD
.RE
.IP " 2." 4
JSON Group Records
.RS 4
\%https://systemd.io/GROUP_RECORD
.RE
.IP " 3." 4
User/Group Record Lookup API via Varlink
.RS 4
\%https://systemd.io/USER_GROUP_API
.RE
|