OPTIONS¶
The following options are understood:
--output=MODE
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.
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 aren't 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.
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.
--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.
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.
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 to use when
--no-pager is not given;
overrides
$PAGER. If neither
$SYSTEMD_PAGER nor
$PAGER
are set, a set of well-known pager implementations are tried in turn,
including
less(1) and
more(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
--no-pager.
Note: if $SYSTEMD_PAGERSECURE is not set,
$SYSTEMD_PAGER (as well as $PAGER) will be silently
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
Takes a boolean argument. When true, the
"secure" mode of the pager is enabled; if false, disabled. If
$SYSTEMD_PAGERSECURE 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
geteuid(2) and
sd_pid_get_owner_uid(3). In secure mode,
LESSSECURE=1 will be set when invoking the pager, and the pager shall
disable commands that open or create new files or start new subprocesses. When
$SYSTEMD_PAGERSECURE is not set at all, pagers which are not known to
implement secure mode will not be used. (Currently only
less(1)
implements secure mode.)
Note: when commands are invoked with elevated privileges, for
example under sudo(8) or pkexec(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 SYSTEMD_PAGERSECURE=0 or not removing it from
the inherited environment allows the user to invoke arbitrary commands. Note
that if the $SYSTEMD_PAGER or $PAGER variables are to be
honoured, $SYSTEMD_PAGERSECURE must be set too. It might be
reasonable to completely disable the pager using --no-pager
instead.
$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.