summaryrefslogtreecommitdiffstats
path: root/man/systemd.time.xml
blob: 4f80a306bfa0cea7696a79dc5deb86387949d8c8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
        "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

<!--
  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
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  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 <http://www.gnu.org/licenses/>.
-->

<refentry id="systemd.time">

        <refentryinfo>
                <title>systemd.time</title>
                <productname>systemd</productname>

                <authorgroup>
                        <author>
                                <contrib>Developer</contrib>
                                <firstname>Lennart</firstname>
                                <surname>Poettering</surname>
                                <email>lennart@poettering.net</email>
                        </author>
                </authorgroup>
        </refentryinfo>

        <refmeta>
                <refentrytitle>systemd.time</refentrytitle>
                <manvolnum>7</manvolnum>
        </refmeta>

        <refnamediv>
                <refname>systemd.time</refname>
                <refpurpose>Time and date specifications</refpurpose>
        </refnamediv>

        <refsect1>
                <title>Description</title>

                <para>In systemd timestamps, timespans, and calendar
                events are displayed and may be specified in closely
                related syntaxes.</para>
        </refsect1>

        <refsect1>
                <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
                unit.</para>

                <programlisting>2h 30min</programlisting>

                <para>All specified time values are meant to be added
                up. The above hence refers to 150 minutes.</para>
        </refsect1>

        <refsect1>
                <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>

                <itemizedlist>
                        <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>
                </itemizedlist>

                <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
2hours
48hr
1y 12month
55s500ms
300ms20s 5day</programlisting>
        </refsect1>

        <refsect1>
                <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>
        </refsect1>

        <refsect1>
                <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
                century).</para>

                <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>yesterday</literal>,
                <literal>tomorrow</literal> refer to 00:00:00 of the
                current day, the day before or the next day,
                respectively.</para>

                <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
                <literal>ago</literal>.</para>

                <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>
        </refsect1>

        <refsect1>
                <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
                matched.</para>

                <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>,
                respectively.</para>

                <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
                  <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>
                  for details.</para>

        </refsect1>

        <refsect1>
                  <title>See Also</title>
                  <para>
                          <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
                          <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
                          <citerefentry><refentrytitle>systemd.timer</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
                          <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry>
                  </para>
        </refsect1>

</refentry>