Commit 7a529f63 authored by Lennart Poettering's avatar Lennart Poettering
Browse files

man: document calendar timers

parent 0979f285
......@@ -477,6 +477,7 @@ MANPAGES = \
man/systemd.kill.5 \
man/systemd.special.7 \
man/systemd.journal-fields.7 \
man/systemd.time.7 \
man/kernel-command-line.7 \
man/daemon.7 \
man/bootup.7 \
......@@ -746,7 +747,8 @@ XML_DIRECTIVE_FILES = \
man/systemd.kill.xml \
man/systemd.device.xml \
man/systemd.conf.xml \
man/systemd.journal-fields.xml \
man/systemd.directives.xml: $(XML_DIRECTIVE_FILES)
$(AM_V_at)$(MKDIR_P) $(dir $@)
<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
This file is part of systemd.
Copyright 2010 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <>.
<refentry id="systemd.time">
<refpurpose>Time and date specifications</refpurpose>
<para>In systemd timestamps, timespans, and calendar
events are displayed and may be specified in closely
related syntaxes.</para>
<title>Displaying Timespans</title>
<para>Timespans refer to time durations. On display
systemd will present timespans as a space separated
series of time values each suffixed by a time
<programlisting>2h 30min</programlisting>
<para>All specified time values are meant to be added
up. The above hence refers to 150 minutes.</para>
<title>Parsing Timespans</title>
<para>When parsing systemd will accept the same
timespan syntax. Separating spaces may be omitted. The
following time units are understood:</para>
<listitem><para>usec, us</para></listitem>
<listitem><para>msec, ms</para></listitem>
<listitem><para>seconds, second, sec, s</para></listitem>
<listitem><para>minutes, minute, min, m</para></listitem>
<listitem><para>hours, hour, hr, h</para></listitem>
<listitem><para>days, day, d</para></listitem>
<listitem><para>weeks, week, w</para></listitem>
<listitem><para>months, month</para></listitem>
<listitem><para>years, year, y</para></listitem>
<para>If no time unit is specified, generally seconds
are assumed, but some exceptions exist and are marked
as such. In a few cases <literal>ns</literal>,
<literal>nsec</literal> is accepted too, where the
granularity of the timespan allows for this.</para>
<para>Examples for valid timespan specifications:</para>
<programlisting>2 h
1y 12month
300ms20s 5day</programlisting>
<title>Displaying Timestamps</title>
<para>Timestamps refer to specific, unique points in
time. On display systemd will format these in the
local timezone as follows:</para>
<programlisting>Fri 2012-11-23 23:02:15 CET</programlisting>
<para>The week day is printed according to the locale
choice of the user.</para>
<title>Parsing Timestamps</title>
<para>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 (<literal>Wed</literal>) or
non-abbreviated (<literal>Wednesday</literal>) 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
<para>A timestamp is considered invalid if a week day
is specified and the date does not actually match the
specified day of the week.</para>
<para>When parsing systemd will also accept a few
special placeholders instead of timestamps:
<literal>now</literal> may be used to refer to the
current time (or of the invocation of the command
that is currently executed). <literal>today</literal>,
<literal>tomorrow</literal> refer to 00:00:00 of the
current day, the day before or the next day,
<para>When parsing systemd will also accept relative
time specifications. A timespan (see above) that is
prefixed with <literal>+</literal> is evaluated to the
current time plus the specified
timespan. Correspondingly a timespan that is prefix
with <literal>-</literal> is evaluated to the current
time minus the specified timespan. Instead of
prefixing the timespan with <literal>-</literal> it
may also be suffixed with a space and the word
<para>Examples for valid timestamps and their
normalized form (assuming the current time was
2012-11-23 18:15:22):</para>
<programlisting>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</programlisting>
<para>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.</para>
<para>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:</para>
<para>2 months 5 days ago</para>
<para>Note that any relative timestamp will also parse
correctly where a timestamp is expected. (see above)</para>
<title>Calendar Events</title>
<para>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:</para>
<programlisting>Thu,Fri 2012-*-1,5 11:12:13</programlisting>
<para>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.</para>
<para>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 colons. Specifying two week
days separated by "-" refers to a range of continuous
week days. "," and "-" may be combined freely.</para>
<para>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
colons. 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
<para>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.</para>
<para>Timezone names may not be specified.</para>
<para>The special expressions
<literal>hourly</literal>, <literal>daily</literal>,
<literal>monthly</literal> and <literal>weekly</literal>
may be used as calendar events which refer to
<literal>*-*-* *:00:00</literal>, <literal>*-*-*
00:00:00</literal>, <literal>*-*-01 00:00:00</literal> and
<literal>Mon *-*-* 00:00:00</literal>,
<para>Examples for valid timestamps and their
normalized form:</para>
<programlisting> 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</programlisting>
<para>Calendar events are used by timer units, see
for details.</para>
<title>See Also</title>
......@@ -105,7 +105,7 @@
<listitem><para>Defines timers
<listitem><para>Defines monotonic timers
relative to different starting points:
<varname>OnActiveSec=</varname> defines a
timer relative to the moment the timer
......@@ -139,8 +139,8 @@
seconds. Example: "OnBootSec=50" means
50s after boot-up. The argument may
also include time units. Example:
"OnBootSec=5h 30min" means 5 hours and 30
minutes after boot-up. For details
"OnBootSec=5h 30min" means 5 hours and
30 minutes after boot-up. For details
about the syntax of time spans see
......@@ -152,14 +152,27 @@
elapse and the configured unit is
started. This is not the case for
timers defined in the other
<para>These are monotonic timers,
independent of wall-clock time and timezones. If the
computer is temporarily suspended, the
monotonic clock stops too.</para>
monotonic clock stops too.</para></listitem>
<listitem><para>Defines realtime
(i.e. wallclock) timers via calendar
event expressions. See
for more information on the syntax of
calendar event
......@@ -185,7 +198,8 @@
......@@ -111,7 +111,7 @@
the values are added up. Example: "50" refers to 50
seconds; "2min 200ms" refers to 2 minutes plus 200
milliseconds, i.e. 120200ms. The following time units
are understood: s, min, h, d, w, ms, us.</para>
are understood: s, min, h, d, w, ms, us. For details see <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
<para>Empty lines and lines starting with # or ; are
ignored. This may be used for commenting. Lines ending
......@@ -1077,6 +1077,7 @@
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