Environment$SYSTEMD_LOG_LEVELThe maximum log level of emitted messages (messages with a higher
log level, i.e. less important ones, will be suppressed). Takes a comma-separated list of values. A
value may be either one of (in order of decreasing importance) emerg,
alert, crit, err,
warning, notice, info,
debug, or an integer in the range 0…7. See
syslog3
for more information. Each value may optionally be prefixed with one of console,
syslog, kmsg or journal followed by a
colon to set the maximum log level for that specific log target (e.g.
SYSTEMD_LOG_LEVEL=debug,console:info specifies to log at debug level except when
logging to the console which should be at info level). Note that the global maximum log level takes
priority over any per target maximum log levels.$SYSTEMD_LOG_COLORA 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
journalctl1 and
other tools that display logs will color messages based on the log level on their own.$SYSTEMD_LOG_TIMEA boolean. If true, console log messages will be prefixed with a
timestamp.This setting is only useful when messages are written directly to the terminal or a file, because
journalctl1 and
other tools that display logs will attach timestamps based on the entry metadata on their own.$SYSTEMD_LOG_LOCATIONA 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.$SYSTEMD_LOG_TIDA boolean. If true, messages will be prefixed with the current
numerical thread ID (TID).Note that the this information is attached as metadata to journal entries anyway. Including it
directly in the message text can nevertheless be convenient when debugging programs.$SYSTEMD_LOG_TARGETThe 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 syslog3,
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_PAGERPager to use when 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
less1 and
more1, 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 .Note: if $SYSTEMD_PAGERSECURE is not set, $SYSTEMD_PAGER
(as well as $PAGER) will be silently ignored.$SYSTEMD_LESSOverride the options passed to less (by default
FRSXMK).Users might want to change two options in particular:This option instructs the pager to exit immediately when
CtrlC is pressed. To allow
less to handle CtrlC
itself to switch back to the pager command prompt, unset this option.If the value of $SYSTEMD_LESS does not include K,
and the pager that is invoked is less,
CtrlC will be ignored by the
executable, and needs to be handled by the pager.This option instructs the pager to not send termcap initialization and deinitialization
strings to the terminal. It is set by default to allow command output to remain visible in the
terminal even after the pager exits. Nevertheless, this prevents some pager functionality from
working, in particular paged output cannot be scrolled with the mouse.See
less1
for more discussion.$SYSTEMD_LESSCHARSETOverride the charset passed to less (by default utf-8, if
the invoking terminal is determined to be UTF-8 compatible).$SYSTEMD_PAGERSECURETakes 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
geteuid2
and sd_pid_get_owner_uid3.
In secure mode, 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
less1
implements secure mode.)Note: when commands are invoked with elevated privileges, for example under sudo8 or
pkexec1, 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, $SYSTEMD_PAGERSECURE must be set too. It might be reasonable to completely
disable the pager using instead.$SYSTEMD_COLORSTakes 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_URLIFYThe 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.