Ubuntu Manpage: loginctl - Control the systemd login manager

Provided by: systemd_251.4-1ubuntu7_amd64

NAME

       loginctl - Control the systemd login manager

SYNOPSIS

       loginctl [OPTIONS...] {COMMAND} [NAME...]

DESCRIPTION

       loginctl may be used to introspect and control the state of the systemd(1) login manager
       systemd-logind.service(8).

COMMANDS

The following commands are understood:

Session Commands
list-sessions
List current sessions.

session-status [ID...]
Show terse runtime status information about one or more sessions, followed by the most
recent log data from the journal. Takes one or more session identifiers as parameters.
If no session identifiers are passed, the status of the caller's session is shown.
This function is intended to generate human-readable output. If you are looking for
computer-parsable output, use show-session instead.

show-session [ID...]
Show properties of one or more sessions or the manager itself. If no argument is
specified, properties of the manager will be shown. If a session ID is specified,
properties of the session are shown. By default, empty properties are suppressed. Use
--all to show those too. To select specific properties to show, use --property=. This
command is intended to be used whenever computer-parsable output is required. Use
session-status if you are looking for formatted human-readable output.

activate [ID]
Activate a session. This brings a session into the foreground if another session is
currently in the foreground on the respective seat. Takes a session identifier as
argument. If no argument is specified, the session of the caller is put into
foreground.

lock-session [ID...], unlock-session [ID...]
Activates/deactivates the screen lock on one or more sessions, if the session supports
it. Takes one or more session identifiers as arguments. If no argument is specified,
the session of the caller is locked/unlocked.

lock-sessions, unlock-sessions
Activates/deactivates the screen lock on all current sessions supporting it.

terminate-session ID...
Terminates a session. This kills all processes of the session and deallocates all
resources attached to the session. If the argument is specified as empty string the
session invoking the command is terminated.

kill-session ID...
Send a signal to one or more processes of the session. Use --kill-who= to select which
process to kill. Use --signal= to select the signal to send. If the argument is
specified as empty string the signal is sent to the session invoking the command.

User Commands
list-users
List currently logged in users.

user-status [USER...]
Show terse runtime status information about one or more logged in users, followed by
the most recent log data from the journal. Takes one or more user names or numeric
user IDs as parameters. If no parameters are passed, the status is shown for the user
of the session of the caller. This function is intended to generate human-readable
output. If you are looking for computer-parsable output, use show-user instead.

show-user [USER...]
Show properties of one or more users or the manager itself. If no argument is
specified, properties of the manager will be shown. If a user is specified, properties
of the user are shown. By default, empty properties are suppressed. Use --all to show
those too. To select specific properties to show, use --property=. This command is
intended to be used whenever computer-parsable output is required. Use user-status if
you are looking for formatted human-readable output.

enable-linger [USER...], disable-linger [USER...]
Enable/disable user lingering for one or more users. If enabled for a specific user, a
user manager is spawned for the user at boot and kept around after logouts. This
allows users who are not logged in to run long-running services. Takes one or more
user names or numeric UIDs as argument. If no argument is specified, enables/disables
lingering for the user of the session of the caller.

See also KillUserProcesses= setting in logind.conf(5).

terminate-user USER...
Terminates all sessions of a user. This kills all processes of all sessions of the
user and deallocates all runtime resources attached to the user. If the argument is
specified as empty string the sessions of the user invoking the command are
terminated.

kill-user USER...
Send a signal to all processes of a user. Use --signal= to select the signal to send.
If the argument is specified as empty string the signal is sent to the sessions of the
user invoking the command.

Seat Commands
list-seats
List currently available seats on the local system.

seat-status [NAME...]
Show terse runtime status information about one or more seats. Takes one or more seat
names as parameters. If no seat names are passed the status of the caller's session's
seat is shown. This function is intended to generate human-readable output. If you are
looking for computer-parsable output, use show-seat instead.

show-seat [NAME...]
Show properties of one or more seats or the manager itself. If no argument is
specified, properties of the manager will be shown. If a seat is specified, properties
of the seat are shown. By default, empty properties are suppressed. Use --all to show
those too. To select specific properties to show, use --property=. This command is
intended to be used whenever computer-parsable output is required. Use seat-status if
you are looking for formatted human-readable output.

attach NAME DEVICE...
Persistently attach one or more devices to a seat. The devices should be specified via
device paths in the /sys/ file system. To create a new seat, attach at least one
graphics card to a previously unused seat name. Seat names may consist only of a–z,
A–Z, 0–9, "-" and "_" and must be prefixed with "seat". To drop assignment of a device
to a specific seat, just reassign it to a different seat, or use flush-devices.

flush-devices
Removes all device assignments previously created with attach. After this call, only
automatically generated seats will remain, and all seat hardware is assigned to them.

terminate-seat NAME...
Terminates all sessions on a seat. This kills all processes of all sessions on the
seat and deallocates all runtime resources attached to them.

OPTIONS

The following options are understood:

--no-ask-password
Do not query the user for authentication for privileged operations.

-p, --property=
When showing session/user/seat properties, limit display to certain properties as
specified as argument. If not specified, all set properties are shown. The argument
should be a property name, such as "Sessions". If specified more than once, all
properties with the specified names are shown.

--value
When showing session/user/seat properties, only print the value, and skip the property
name and "=".

-a, --all
When showing session/user/seat properties, show all properties regardless of whether
they are set or not.

-l, --full
Do not ellipsize process tree entries.

--kill-who=
When used with kill-session, choose which processes to kill. Must be one of leader, or
all to select whether to kill only the leader process of the session or all processes
of the session. If omitted, defaults to all.

-s, --signal=
When used with kill-session or kill-user, choose which signal to send to selected
processes. Must be one of the well known signal specifiers, such as SIGTERM, SIGINT or
SIGSTOP. If omitted, defaults to SIGTERM.

The special value "help" will list the known values and the program will exit
immediately, and the special value "list" will list known values along with the
numerical signal numbers and the program will exit immediately.

-n, --lines=
When used with user-status and session-status, controls the number of journal lines to
show, counting from the most recent ones. Takes a positive integer argument. Defaults
to 10.

-o, --output=
When used with user-status and session-status, controls the formatting of the journal
entries that are shown. For the available choices, see journalctl(1). Defaults to
"short".

-H, --host=
Execute the operation remotely. Specify a hostname, or a username and hostname
separated by "@", to connect to. The hostname may optionally be suffixed by a port ssh
is listening on, separated by ":", and then a container name, separated by "/", which
connects directly to a specific container on the specified host. This will use SSH to
talk to the remote machine manager instance. Container names may be enumerated with
machinectl -H HOST. Put IPv6 addresses in brackets.

-M, --machine=
Execute operation on a local container. Specify a container name to connect to,
optionally prefixed by a user name to connect as and a separating "@" character. If
the special string ".host" is used in place of the container name, a connection to the
local system is made (which is useful to connect to a specific user's user bus:
"--user --machine=lennart@.host"). If the "@" syntax is not used, the connection is
made as root user. If the "@" syntax is used either the left hand side or the right
hand side may be omitted (but not both) in which case the local user name and ".host"
are implied.

--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.

EXIT STATUS

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

EXAMPLES

       Example 1. Querying user status

           $ loginctl user-status
           fatima (1005)
                      Since: Sat 2016-04-09 14:23:31 EDT; 54min ago
                      State: active
                   Sessions: 5 *3
                       Unit: user-1005.slice
                             ├─user@1005.service
                               ...
                             ├─session-3.scope
                               ...
                             └─session-5.scope
                               ├─3473 login -- fatima
                               └─3515 -zsh

           Apr 09 14:40:30 laptop login[2325]: pam_unix(login:session):
                                  session opened for user fatima by LOGIN(uid=0)
           Apr 09 14:40:30 laptop login[2325]: LOGIN ON tty3 BY fatima

       There are two sessions, 3 and 5. Session 3 is a graphical session, marked with a star. The
       tree of processing including the two corresponding scope units and the user manager unit
       are shown.

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). 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.

$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_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.

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).

$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.