Provided by: systemd_204-5ubuntu20.31_amd64 
NAME
systemd.time - Time and date specifications
DESCRIPTION
In systemd timestamps, timespans, and calendar events are displayed and may be specified in closely
related syntaxes.
DISPLAYING TIMESPANS
Timespans refer to time durations. On display systemd will present timespans as a space separated series
of time values each suffixed by a time unit.
2h 30min
All specified time values are meant to be added up. The above hence refers to 150 minutes.
PARSING TIMESPANS
When parsing systemd will accept the same timespan syntax. Separating spaces may be omitted. The
following time units are understood:
• usec, us
• msec, ms
• seconds, second, sec, s
• minutes, minute, min, m
• hours, hour, hr, h
• days, day, d
• weeks, week, w
• months, month
• years, year, y
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 timespan allows for this.
Examples for valid timespan specifications:
2 h
2hours
48hr
1y 12month
55s500ms
300ms20s 5day
DISPLAYING TIMESTAMPS
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 week day is printed according to the locale choice of the user.
PARSING TIMESTAMPS
When parsing systemd will accept a similar timestamp syntax, but excluding any timezone specification
(this limitation might be removed eventually). The week day specification is optional, but when the week
day is specified it must either be in the abbreviated (Wed) or non-abbreviated (Wednesday) english
language form (case doesn't 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, resp., 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 century).
A timestamp is considered invalid if a week day is specified and the date does not actually 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, 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 timespan (see above) that is
prefixed with + is evaluated to the current time plus the specified timespan. Correspondingly a timespan
that is prefix with - is evaluated to the current time minus the specified timespan. Instead of prefixing
the timespan with - it may also be suffixed with a space and the word ago.
Examples for valid timestamps and their normalized form (assuming the current time was 2012-11-23
18:15:22):
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 → 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
yesterday → Fri 2012-11-22 00:00:00
tomorrow → Fri 2012-11-24 00:00:00
+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
Note that timestamps printed by systemd will not be parsed correctly by systemd, as the timezone
specification is not accepted, and printing timestamps is subject to locale settings for the week day
while parsing only accepts english week day names.
In some cases systemd will display a relative timestamp (relative to the current time, or the time of
invocation of the command) instead or in addition to an absolute timestamp as described above. A relative
timestamp is formatted as follows:
2 months 5 days ago
Note that any relative timestamp will also parse correctly where a timestamp is expected. (see above)
CALENDAR EVENTS
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, given that it is a
thursday or friday.
The weekday specification is optional. If specified it should consist of one or more english language
week day names, either in the abbreviated (Wed) or non-abbreviated (Wednesday) form (case does not
matter), separated by commas. Specifying two week days separated by "-" refers to a range of continuous
week days. "," 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 list of values separated by commas. Values may
also be suffixed with "/" and a repetition value, which indicates that the value and all values plus
multiples of the repetition value are matched.
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 names may not be specified.
The special expressions hourly, daily, monthly and weekly may be used as calendar events which refer to
*-*-* *:00:00, *-*-* 00:00:00, *-*-01 00:00:00 and Mon *-*-* 00:00:00, respectively.
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
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
2003-03-05 → 2003-03-05 00:00:00
03-05 → *-03-05 00:00:00
hourly → *-*-* *:00:00
daily → *-*-* 00:00:00
monthly → *-*-01 00:00:00
weekly → Mon *-*-* 00:00:00
*:2/3 → *-*-* *:02/3:00
Calendar events are used by timer units, see systemd.timer(5) for details.
SEE ALSO
systemd(1), journalctl(1), systemd.timer(5), systemd.unit(5), systemd.directives(7)
systemd 204 SYSTEMD.TIME(7)