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<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>systemd.time</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><style>
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<a href="../libudev/index.html">gudev </a><span style="float:right">systemd 215</span><hr><div class="refentry"><a name="systemd.time"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>systemd.time — Time and date specifications</p></div><div class="refsect1"><a name="idm214177369584"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description">¶</a></h2><p>In systemd, timestamps, time spans, and calendar
events are displayed and may be specified in closely
related syntaxes.</p></div><div class="refsect1"><a name="idm214173533376"></a><h2 id="Displaying Time Spans">Displaying Time Spans<a class="headerlink" title="Permalink to this headline" href="#Displaying%20Time%20Spans">¶</a></h2><p>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.</p><pre class="programlisting">2h 30min</pre><p>All specified time values are meant to be added
up. The above hence refers to 150 minutes.</p></div><div class="refsect1"><a name="idm214173530880"></a><h2 id="Parsing Time Spans">Parsing Time Spans<a class="headerlink" title="Permalink to this headline" href="#Parsing%20Time%20Spans">¶</a></h2><p>When parsing, systemd will accept the same
time span syntax. Separating spaces may be omitted. The
following time units are understood:</p><div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "><li class="listitem"><p>usec, us</p></li><li class="listitem"><p>msec, ms</p></li><li class="listitem"><p>seconds, second, sec, s</p></li><li class="listitem"><p>minutes, minute, min, m</p></li><li class="listitem"><p>hours, hour, hr, h</p></li><li class="listitem"><p>days, day, d</p></li><li class="listitem"><p>weeks, week, w</p></li><li class="listitem"><p>months, month</p></li><li class="listitem"><p>years, year, y</p></li></ul></div><p>If no time unit is specified, generally seconds
are assumed, but some exceptions exist and are marked
as such. In a few cases "<code class="literal">ns</code>",
"<code class="literal">nsec</code>" is accepted too, where the
granularity of the time span allows for this.</p><p>Examples for valid time span specifications:</p><pre class="programlisting">2 h
2hours
48hr
1y 12month
55s500ms
300ms20s 5day</pre></div><div class="refsect1"><a name="idm214173521216"></a><h2 id="Displaying Timestamps">Displaying Timestamps<a class="headerlink" title="Permalink to this headline" href="#Displaying%20Timestamps">¶</a></h2><p>Timestamps refer to specific, unique points in
time. On display, systemd will format these in the
local timezone as follows:</p><pre class="programlisting">Fri 2012-11-23 23:02:15 CET</pre><p>The weekday is printed according to the locale
choice of the user.</p></div><div class="refsect1"><a name="idm214173518768"></a><h2 id="Parsing Timestamps">Parsing Timestamps<a class="headerlink" title="Permalink to this headline" href="#Parsing%20Timestamps">¶</a></h2><p>When parsing systemd will accept a similar
timestamp syntax, but excluding any timezone
specification (this limitation might be removed
eventually). The weekday specification is optional,
but when the weekday is specified it must either be
in the abbreviated ("<code class="literal">Wed</code>") or
non-abbreviated ("<code class="literal">Wednesday</code>") 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, 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).</p><p>A timestamp is considered invalid if a weekday
is specified and the date does not actually match the
specified day of the week.</p><p>When parsing, systemd will also accept a few
special placeholders instead of timestamps:
"<code class="literal">now</code>" may be used to refer to the
current time (or of the invocation of the command
that is currently executed). "<code class="literal">today</code>",
"<code class="literal">yesterday</code>",
"<code class="literal">tomorrow</code>" refer to 00:00:00 of the
current day, the day before or the next day,
respectively.</p><p>When parsing, systemd will also accept relative
time specifications. A time span (see above) that is
prefixed with "<code class="literal">+</code>" is evaluated to the
current time plus the specified time
span. Correspondingly, a time span that is prefixed
with "<code class="literal">-</code>" is evaluated to the current
time minus the specified time span. Instead of
prefixing the time span with "<code class="literal">+</code>" or
"<code class="literal">-</code>", it may also be suffixed with a
space and the word "<code class="literal">left</code>" or
"<code class="literal">ago</code>".</p><p>Finally, a timespan prefixed with
"<code class="literal">@</code>" is evaluated relative to the UNIX
time epoch 1st Jan, 1970, 00:00.</p><p>Examples for valid timestamps and their
normalized form (assuming the current time was
2012-11-23 18:15:22):</p><pre class="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
@1395716396 → Tue 2014-03-25 03:59:56</pre><p>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 weekday while
parsing only accepts English weekday names.</p><p>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:</p><p>2 months 5 days ago</p><p>Note that any relative timestamp will also parse
correctly where a timestamp is expected. (see above)</p></div><div class="refsect1"><a name="idm214177428256"></a><h2 id="Calendar Events">Calendar Events<a class="headerlink" title="Permalink to this headline" href="#Calendar%20Events">¶</a></h2><p>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:</p><pre class="programlisting">Thu,Fri 2012-*-1,5 11:12:13</pre><p>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.</p><p>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 "<code class="literal">-</code>" refers to a
range of continuous weekdays. "<code class="literal">,</code>" and
"<code class="literal">-</code>" may be combined freely.</p><p>In the date and time specifications, any
component may be specified as "<code class="literal">*</code>" in
which case any value will match. Alternatively, each
component can be specified as a list of values separated
by commas. Values may also be suffixed with
"<code class="literal">/</code>" and a repetition value, which
indicates that the value and all values plus multiples
of the repetition value are matched.</p><p>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, "<code class="literal">:00</code>" is assumed.</p><p>Timezone names may not be specified.</p><p>The special expressions
"<code class="literal">hourly</code>", "<code class="literal">daily</code>",
"<code class="literal">monthly</code>" and "<code class="literal">weekly</code>"
may be used as calendar events which refer to
"<code class="literal">*-*-* *:00:00</code>", "<code class="literal">*-*-*
00:00:00</code>", "<code class="literal">*-*-01 00:00:00</code>" and
"<code class="literal">Mon *-*-* 00:00:00</code>",
respectively.</p><p>Examples for valid timestamps and their
normalized form:</p><pre class="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</pre><p>Calendar events are used by timer units, see
<a href="systemd.timer.html"><span class="citerefentry"><span class="refentrytitle">systemd.timer</span>(5)</span></a>
for details.</p></div><div class="refsect1"><a name="idm214172453600"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also">¶</a></h2><p>
<a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
<a href="journalctl.html"><span class="citerefentry"><span class="refentrytitle">journalctl</span>(1)</span></a>,
<a href="systemd.timer.html"><span class="citerefentry"><span class="refentrytitle">systemd.timer</span>(5)</span></a>,
<a href="systemd.unit.html"><span class="citerefentry"><span class="refentrytitle">systemd.unit</span>(5)</span></a>,
<a href="systemd.directives.html"><span class="citerefentry"><span class="refentrytitle">systemd.directives</span>(7)</span></a>
</p></div></div></body></html>
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