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   systemd    ( 1 )

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Окружение (Environment)

The environment block for the system manager is initially set by the kernel. (In particular, "key=value" assignments on the kernel command line are returned into environment variables for PID 1). For the user manager, the system manager sets the environment as described in the "Environment Variables in Spawned Processes" section of systemd.exec(5). The DefaultEnvironment= setting in the system manager applies to all services including user@.service. Additional entries may be configured (as for any other service) through the Environment= and EnvironmentFile= settings for user@.service (see systemd.exec(5)). Also, additional environment variables may be set through the ManagerEnvironment= setting in systemd-system.conf(5) and systemd-user.conf(5).

Some of the variables understood by systemd:

$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.

This can be overridden with --log-level=.

$SYSTEMD_LOG_COLOR A boolean. If true, messages written to the tty will be colored according to priority.

This can be overridden with --log-color=.

$SYSTEMD_LOG_TIME A boolean. If true, console log messages will be prefixed with a timestamp.

This can be overridden with --log-time=.

$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.

This can be overridden with --log-location=.

$SYSTEMD_LOG_TID A boolean. If true, messages will be prefixed with the current numerical thread ID (TID).

$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).

This can be overridden with --log-target=.

$XDG_CONFIG_HOME, $XDG_CONFIG_DIRS, $XDG_DATA_HOME, $XDG_DATA_DIRS The systemd user manager uses these variables in accordance to the XDG Base Directory specification[6] to find its configuration.

$SYSTEMD_UNIT_PATH, $SYSTEMD_GENERATOR_PATH, $SYSTEMD_ENVIRONMENT_GENERATOR_PATH Controls where systemd looks for unit files and generators.

These variables may contain a list of paths, separated by colons (":"). When set, if the list ends with an empty component ("...:"), this list is prepended to the usual set of paths. Otherwise, the specified list replaces the usual set of paths.

$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.

$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.

$LISTEN_PID, $LISTEN_FDS, $LISTEN_FDNAMES Set by systemd for supervised processes during socket-based activation. See sd_listen_fds(3) for more information.

$NOTIFY_SOCKET Set by systemd for supervised processes for status and start-up completion notification. See sd_notify(3) for more information.

For further environment variables understood by systemd and its various components, see Known Environment Variables[7].