systemd.time(7) — Linux manual page


SYSTEMD.TIME(7)                 systemd.time                 SYSTEMD.TIME(7)

NAME         top

       systemd.time - Time and date specifications

DESCRIPTION         top

       In systemd, timestamps, time spans, and calendar events are displayed
       and may be specified in closely related syntaxes.


       Time spans refer to time durations. On display, systemd will present
       time spans as a space-separated series of time values each suffixed
       by a time unit. Example:

           2h 30min

       All specified time values are meant to be added up. The above hence
       refers to 150 minutes. Display is locale-independent, only English
       names for the time units are used.


       When parsing, systemd will accept the same time span syntax.
       Separating spaces may be omitted. The following time units are

       ·   usec, us, µs

       ·   msec, ms

       ·   seconds, second, sec, s

       ·   minutes, minute, min, m

       ·   hours, hour, hr, h

       ·   days, day, d

       ·   weeks, week, w

       ·   months, month, M (defined as 30.44 days)

       ·   years, year, y (defined as 365.25 days)

       If no time unit is specified, generally seconds are assumed, but some
       exceptions exist and are marked as such. In a few cases "ns", "nsec"
       is accepted too, where the granularity of the time span permits this.
       Parsing is generally locale-independent, non-English names for the
       time units are not accepted.

       Examples for valid time span specifications:

           2 h
           1y 12month
           300ms20s 5day

       One can use the timespan command of systemd-analyze(1) to normalise a
       textual time span for testing and validation purposes.


       Timestamps refer to specific, unique points in time. On display,
       systemd will format these in the local timezone as follows:

           Fri 2012-11-23 23:02:15 CET

       The weekday is printed in the abbreviated English language form. The
       formatting is locale-independent.

       In some cases timestamps are shown in the UTC timezone instead of the
       local timezone, which is indicated via the "UTC" timezone specifier
       in the output.

       In some cases timestamps are shown with microsecond granularity. In
       this case the sub-second remainder is separated by a full stop from
       the seconds component.


       When parsing, systemd will accept a similar syntax, but expects no
       timezone specification, unless it is given as the literal string
       "UTC" (for the UTC timezone), or is specified to be the locally
       configured timezone, or the timezone name in the IANA timezone
       database format. The complete list of timezones supported on your
       system can be obtained using the "timedatectl list-timezones" (see
       timedatectl(1)). Using IANA format is recommended over local timezone
       names, as less prone to errors (e.g. with local timezone it's
       possible to specify daylight saving time in winter, even though that
       is not correct). The weekday specification is optional, but when the
       weekday is specified, it must either be in the abbreviated ("Wed") or
       non-abbreviated ("Wednesday") English language form (case does not
       matter), and is not subject to the locale choice of the user. Either
       the date, or the time part may be omitted, in which case the current
       date or 00:00:00, respectively, is assumed. The seconds component of
       the time may also be omitted, in which case ":00" is assumed. Year
       numbers may be specified in full or may be abbreviated (omitting the

       A timestamp is considered invalid if a weekday is specified and the
       date does not match the specified day of the week.

       When parsing, systemd will also accept a few special placeholders
       instead of timestamps: "now" may be used to refer to the current time
       (or of the invocation of the command that is currently executed).
       "today", "yesterday", and "tomorrow" refer to 00:00:00 of the current
       day, the day before, or the next day, respectively.

       When parsing, systemd will also accept relative time specifications.
       A time span (see above) that is prefixed with "+" is evaluated to the
       current time plus the specified time span. Correspondingly, a time
       span that is prefixed with "-" is evaluated to the current time minus
       the specified time span. Instead of prefixing the time span with "+"
       or "-", it may also be suffixed with a space and the word "left" or

       Finally, a timespan prefixed with "@" is evaluated relative to the
       UNIX time epoch 1st Jan, 1970, 00:00.

       Examples for valid timestamps and their normalized form (assuming the
       current time was 2012-11-23 18:15:22 and the timezone was UTC+8, for
       example "TZ=:Asia/Shanghai"):

             Fri 2012-11-23 11:12:13 → Fri 2012-11-23 11:12:13
                 2012-11-23 11:12:13 → Fri 2012-11-23 11:12:13
             2012-11-23 11:12:13 UTC → Fri 2012-11-23 19:12:13
                          2012-11-23 → Fri 2012-11-23 00:00:00
                            12-11-23 → Fri 2012-11-23 00:00:00
                            11:12:13 → Fri 2012-11-23 11:12:13
                               11:12 → Fri 2012-11-23 11:12:00
                                 now → Fri 2012-11-23 18:15:22
                               today → Fri 2012-11-23 00:00:00
                           today UTC → Fri 2012-11-23 16:00:00
                           yesterday → Fri 2012-11-22 00:00:00
                            tomorrow → Fri 2012-11-24 00:00:00
           tomorrow Pacific/Auckland → Thu 2012-11-23 19:00:00
                            +3h30min → Fri 2012-11-23 21:45:22
                                 -5s → Fri 2012-11-23 18:15:17
                           11min ago → Fri 2012-11-23 18:04:22
                         @1395716396 → Tue 2014-03-25 03:59:56

       Note that timestamps displayed by remote systems with a non-matching
       timezone are usually not parsable locally, as the timezone component
       is not understood (unless it happens to be "UTC").

       Timestamps may also be specified with microsecond granularity. The
       sub-second remainder is expected separated by a full stop from the
       seconds component. Example:

           2014-03-25 03:59:56.654563

       In some cases, systemd will display a relative timestamp (relative to
       the current time, or the time of invocation of the command) instead
       of or in addition to an absolute timestamp as described above. A
       relative timestamp is formatted as follows:

           2 months 5 days ago

       Note that a relative timestamp is also accepted where a timestamp is
       expected (see above).

       Use the timestamp command of systemd-analyze(1) to validate and
       normalize timestamps for testing purposes.


       Calendar events may be used to refer to one or more points in time in
       a single expression. They form a superset of the absolute timestamps
       explained above:

           Thu,Fri 2012-*-1,5 11:12:13

       The above refers to 11:12:13 of the first or fifth day of any month
       of the year 2012, but only if that day is a Thursday or Friday.

       The weekday specification is optional. If specified, it should
       consist of one or more English language weekday names, either in the
       abbreviated (Wed) or non-abbreviated (Wednesday) form (case does not
       matter), separated by commas. Specifying two weekdays separated by
       ".."  refers to a range of continuous weekdays.  "," and ".."  may be
       combined freely.

       In the date and time specifications, any component may be specified
       as "*" in which case any value will match. Alternatively, each
       component can be specified as a list of values separated by commas.
       Values may be suffixed with "/" and a repetition value, which
       indicates that the value itself and the value plus all multiples of
       the repetition value are matched. Two values separated by ".."  may
       be used to indicate a range of values; ranges may also be followed
       with "/" and a repetition value, in which case the expression matches
       all times starting with the start value, and continuing with all
       multiples of the repetition value relative to the start value, ending
       at the end value the latest.

       A date specification may use "~" to indicate the last day(s) in a
       month. For example, "*-02~03" means "the third last day in February,"
       and "Mon *-05~07/1" means "the last Monday in May."

       The seconds component may contain decimal fractions both in the value
       and the repetition. All fractions are rounded to 6 decimal places.

       Either time or date specification may be omitted, in which case the
       current day and 00:00:00 is implied, respectively. If the second
       component is not specified, ":00" is assumed.

       Timezone can be specified as the literal string "UTC", or the local
       timezone, similar to the supported syntax of timestamps (see above),
       or the timezone in the IANA timezone database format (also see

       The following special expressions may be used as shorthands for
       longer normalized forms:

               minutely → *-*-* *:*:00
                 hourly → *-*-* *:00:00
                  daily → *-*-* 00:00:00
                monthly → *-*-01 00:00:00
                 weekly → Mon *-*-* 00:00:00
                 yearly → *-01-01 00:00:00
              quarterly → *-01,04,07,10-01 00:00:00
           semiannually → *-01,07-01 00:00:00

       Examples for valid timestamps and their normalized form:

             Sat,Thu,Mon..Wed,Sat..Sun → Mon..Thu,Sat,Sun *-*-* 00:00:00
                 Mon,Sun 12-*-* 2,1:23 → Mon,Sun 2012-*-* 01,02:23:00
                               Wed *-1 → Wed *-*-01 00:00:00
                      Wed..Wed,Wed *-1 → Wed *-*-01 00:00:00
                            Wed, 17:48 → Wed *-*-* 17:48:00
           Wed..Sat,Tue 12-10-15 1:2:3 → Tue..Sat 2012-10-15 01:02:03
                           *-*-7 0:0:0 → *-*-07 00:00:00
                                 10-15 → *-10-15 00:00:00
                   monday *-12-* 17:00 → Mon *-12-* 17:00:00
             Mon,Fri *-*-3,1,2 *:30:45 → Mon,Fri *-*-01,02,03 *:30:45
                  12,14,13,12:20,10,30 → *-*-* 12,13,14:10,20,30:00
                       12..14:10,20,30 → *-*-* 12..14:10,20,30:00
             mon,fri *-1/2-1,3 *:30:45 → Mon,Fri *-01/2-01,03 *:30:45
                        03-05 08:05:40 → *-03-05 08:05:40
                              08:05:40 → *-*-* 08:05:40
                                 05:40 → *-*-* 05:40:00
                Sat,Sun 12-05 08:05:40 → Sat,Sun *-12-05 08:05:40
                      Sat,Sun 08:05:40 → Sat,Sun *-*-* 08:05:40
                      2003-03-05 05:40 → 2003-03-05 05:40:00
            05:40:23.4200004/3.1700005 → *-*-* 05:40:23.420000/3.170001
                        2003-02..04-05 → 2003-02..04-05 00:00:00
                  2003-03-05 05:40 UTC → 2003-03-05 05:40:00 UTC
                            2003-03-05 → 2003-03-05 00:00:00
                                 03-05 → *-03-05 00:00:00
                                hourly → *-*-* *:00:00
                                 daily → *-*-* 00:00:00
                             daily UTC → *-*-* 00:00:00 UTC
                               monthly → *-*-01 00:00:00
                                weekly → Mon *-*-* 00:00:00
               weekly Pacific/Auckland → Mon *-*-* 00:00:00 Pacific/Auckland
                                yearly → *-01-01 00:00:00
                              annually → *-01-01 00:00:00
                                 *:2/3 → *-*-* *:02/3:00

       Calendar events are used by timer units, see systemd.timer(5) for

       Use the calendar command of systemd-analyze(1) to validate and
       normalize calendar time specifications for testing purposes. The tool
       also calculates when a specified calendar event would occur next.

SEE ALSO         top

       systemd(1), journalctl(1), systemd.timer(5), systemd.unit(5),
       systemd.directives(7), systemd-analyze(1)

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
       project.  Information about the project can be found at 
       ⟨⟩.  If you have a bug
       report for this manual page, see
       ⟨⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨⟩ on 2020-07-14.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2020-07-14.)  If you discover any rendering problems in
       this HTML version of the page, or you believe there is a better or
       more up-to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not part
       of the original manual page), send a mail to

systemd 246                                                  SYSTEMD.TIME(7)

Pages that refer to this page: homectl(1)journalctl(1)systemd-analyze(1)systemd-mount(1)systemd-umount(1)systemd.exec(5)systemd.socket(5)systemd.timer(5)systemd.unit(5)30-systemd-environment-d-generator(7)systemd.index(7)systemd.syntax(7)