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

       Internally, systemd generally operates with microsecond time
       granularity, while the default time unit in user-configurable
       time spans is usually seconds (see above). This disparity becomes
       visible when comparing the same settings in the (high-level) unit
       file syntax with the matching (more low-level) D-Bus properties
       (which are what systemctl(1)'s show command displays). The former
       typically are suffixed with "...Sec" to indicate the default unit
       of seconds, the latter are typically suffixed with "...USec" to
       indicate the underlying low-level time unit, even if they both
       encapsulate the very same settings.


       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 some
       fields can be omitted, and the space between the date and time
       can be replaced with a "T" (à la the RFC 3339[1] profile of ISO
       8601); thus, in CET, the following are all identical: "Fri
       2012-11-23 23:02:15 CET", "Fri 2012-11-23T23:02:15",
       "2012-11-23T23:02:15 CET", "2012-11-23 23:02:15".

       The timezone defaults to the current timezone if not specified
       explicitly. It may be given after a space, like above, in which
       case it can be: "UTC", an entry in the installed IANA timezone
       database ("CET", "Asia/Tokyo", &c.; complete list obtainable with
       "timedatectl list-timezones" (see timedatectl(1))), or "±05",
       "±0530", "±05:30", "Z".

       It may also be affixed directly to the timestamp, in which case
       it must correspond to one of the formats defined in the RFC
       3339[1] profile of ISO 8601: "±05:30" or "Z". Thus, the following
       are also identical to the above: "2012-11-23T23:02:15+01:00",
       "2012-11-23 22:02:15Z".

       A timestamp can start with a field containing a weekday, which
       can be in an abbreviated ("Wed") or non-abbreviated ("Wednesday")
       English language form (case does not matter), regardless of the
       locale. However, if a weekday is specified and doesn't match the
       date, the timestamp is rejected.

       If the date is omitted, it defaults to today. If the time is
       omitted, it defaults to 00:00:00. Fractional seconds can be
       specified down to 1µs precision. The seconds field can also be
       omitted, defaulting to 0.

       There are special tokens that can be used in place 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.

       Relative times are also accepted: a time span (see above)
       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 "ago".

       Finally, an integer prefixed with "@" is evaluated relative to
       the UNIX epoch – 1970-01-01 00:00:00 UTC.

       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
                2012-11-23T11:12:13Z → Fri 2012-11-23 19:12:13
              2012-11-23T11:12+02:00 → Fri 2012-11-23 17:12:00
                          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

       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

       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 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

       Either time or date specification may be omitted, in which case
       *-*-* and 00:00:00 is implied, respectively. If the seconds
       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 above).

       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

SEE ALSO         top

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

NOTES         top

        1. RFC 3339

COLOPHON         top

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systemd 255                                              SYSTEMD.TIME(7)

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