Show information about targets and their versions.

When no TARGET is specified, this command lists all available targets. When a TARGET is specified without a VERSION, this command lists all known versions of the specified target. If a VERSION is specified, this command lists all known information about the specific version.

See the example below for details of the output.

Added in version 257.

Check if any updates are available for the specified targets. If no targets are specified, all available targets will be checked for updates.

See the example below for details of the output.

Added in version 257.

Update the specified targets to the specified versions. If a target is specified without a version, then it will be updated to the latest version. If no targets are specified, then all available targets will be updated to the latest version.

Added in version 257.

Clean up old versions of the specified targets. If no targets are specified, all available targets will be vacuumed.

Added in version 257.

When no FEATURE is specified, this command lists all optional features. When a FEATURE is specified, this command lists all known information about that feature.

Added in version 257.

These commands enable or disable optional features. See sysupdate.features(5). These commands always operate on the host system.

By default, these commands will only change the system's configuration by creating or deleting drop-in files; they will not immediately download the enabled features, or clean up after the disabled ones. Enabled features will be downloaded and installed the next time the target is updated, and disabled transfers will be cleaned up the next time the target is updated or vacuumed. Pass --now to immediately apply these changes.

Added in version 257.

Print a short help text and exit.

Print a short version string and exit.

When used with the update command, reboots the system after updates finish applying. If any update fails, the system will not reboot.

When used with the enable or disable commands and the --now flag, reboots the system after download or clean-up finish applying.

Added in version 257.

When used with the list command, disables fetching metadata from the network. This makes the list command only return information that is available locally (i.e. about versions already installed on the system).

Added in version 257.

When used with the enable command, downloads and installs the enabled features. When used with the disable command, deletes all resources downloaded by the disabled features.

Added in version 257.

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.

Do not pipe output into a pager.

Do not print the legend, i.e. column headers and the footer with hints.

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.

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.

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.

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.

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.

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).

Whether to ratelimit kmsg or not. Takes a boolean. Defaults to "true". If disabled, systemd will not ratelimit messages written to kmsg.

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.

Override the options passed to less (by default "FRSXMK").

Users might want to change two options in particular:

Note that setting the regular $LESS environment variable has no effect for less invocations by systemd tools.

See less(1) for more discussion.

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.

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.

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.

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.