summaryrefslogtreecommitdiff
path: root/man/journalctl.xml
blob: 5af98c67cbc50da7ba3550957105dfe320bb43e3 (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
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
<?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 2012 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="journalctl"
            xmlns:xi="http://www.w3.org/2001/XInclude">

    <refentryinfo>
      <title>journalctl</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>journalctl</refentrytitle>
      <manvolnum>1</manvolnum>
    </refmeta>

    <refnamediv>
      <refname>journalctl</refname>
      <refpurpose>Query the systemd journal</refpurpose>
    </refnamediv>

    <refsynopsisdiv>
      <cmdsynopsis>
        <command>journalctl</command>
        <arg choice="opt" rep="repeat">OPTIONS</arg>
        <arg choice="opt" rep="repeat">MATCHES</arg>
      </cmdsynopsis>
    </refsynopsisdiv>

    <refsect1>
      <title>Description</title>

      <para><command>journalctl</command> may be used to query the
      contents of the
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
      journal as written by
      <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>

      <para>If called without parameters, it will show the full
      contents of the journal, starting with the oldest entry
      collected.</para>

      <para>If one or more match arguments are passed, the output is
      filtered accordingly. A match is in the format
      <literal>FIELD=VALUE</literal>,
      e.g. <literal>_SYSTEMD_UNIT=httpd.service</literal>, referring
      to the components of a structured journal entry. See
      <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
      for a list of well-known fields. If multiple matches are
      specified matching different fields, the log entries are
      filtered by both, i.e. the resulting output will show only
      entries matching all the specified matches of this kind. If two
      matches apply to the same field, then they are automatically
      matched as alternatives, i.e. the resulting output will show
      entries matching any of the specified matches for the same
      field. Finally, the character <literal>+</literal> may appear
      as a separate word between other terms on the command line. This
      causes all matches before and after to be combined in a
      disjunction (i.e. logical OR).</para>

      <para>As shortcuts for a few types of field/value matches, file
      paths may be specified. If a file path refers to an executable
      file, this is equivalent to an <literal>_EXE=</literal> match
      for the canonicalized binary path. Similarly, if a path refers
      to a device node, this is equivalent to a
      <literal>_KERNEL_DEVICE=</literal> match for the device.</para>

      <para>Additional constraints may be added using options
      <option>--boot</option>, <option>--unit=</option>, etc., to
      further limit what entries will be shown (logical AND).</para>

      <para>Output is interleaved from all accessible journal files,
      whether they are rotated or currently being written, and
      regardless of whether they belong to the system itself or are
      accessible user journals.</para>

      <para>The set of journal files which will be used can be
      modified using the <option>--user</option>,
      <option>--system</option>, <option>--directory</option>, and
      <option>--file</option> options, see below.</para>

      <para>All users are granted access to their private per-user
      journals. However, by default, only root and users who are
      members of a few special groups are granted access to the system
      journal and the journals of other users. Members of the groups
      <literal>systemd-journal</literal>, <literal>adm</literal>, and
      <literal>wheel</literal> can read all journal files. Note
      that the two latter groups traditionally have additional
      privileges specified by the distribution. Members of the
      <literal>wheel</literal> group can often perform administrative
      tasks.</para>

      <para>The output is paged through <command>less</command> by
      default, and long lines are "truncated" to screen width. The
      hidden part can be viewed by using the left-arrow and
      right-arrow keys. Paging can be disabled; see the
      <option>--no-pager</option> option and the "Environment" section
      below.</para>

      <para>When outputting to a tty, lines are colored according to
      priority: lines of level ERROR and higher are colored red; lines
      of level NOTICE and higher are highlighted; other lines are
      displayed normally.</para>
    </refsect1>

    <refsect1>
      <title>Options</title>

      <para>The following options are understood:</para>

      <variablelist>
        <varlistentry>
          <term><option>--no-full</option></term>
          <term><option>--full</option></term>
          <term><option>-l</option></term>

          <listitem><para>Ellipsize fields when they do not fit in
          available columns.  The default is to show full fields,
          allowing them to wrap or be truncated by the pager, if one
          is used.</para>

          <para>The old options
          <option>-l</option>/<option>--full</option> are not useful
          anymore, except to undo <option>--no-full</option>.</para>
          </listitem>
        </varlistentry>

        <varlistentry>
          <term><option>-a</option></term>
          <term><option>--all</option></term>

          <listitem><para>Show all fields in full, even if they
          include unprintable characters or are very
          long.</para></listitem>
        </varlistentry>

        <varlistentry>
          <term><option>-f</option></term>
          <term><option>--follow</option></term>

          <listitem><para>Show only the most recent journal entries,
          and continuously print new entries as they are appended to
          the journal.</para></listitem>
        </varlistentry>

        <varlistentry>
          <term><option>-e</option></term>
          <term><option>--pager-end</option></term>

          <listitem><para>Immediately jump to the end of the journal
          inside the implied pager tool. This implies
          <option>-n1000</option> to guarantee that the pager will not
          buffer logs of unbounded size. This may be overridden with
          an explicit <option>-n</option> with some other numeric
          value, while <option>-nall</option> will disable this cap.
          Note that this option is only supported for the
          <citerefentry project='man-pages'><refentrytitle>less</refentrytitle><manvolnum>1</manvolnum></citerefentry>
          pager.</para></listitem>
        </varlistentry>

        <varlistentry>
          <term><option>-n</option></term>
          <term><option>--lines=</option></term>

          <listitem><para>Show the most recent journal events and
          limit the number of events shown. If
          <option>--follow</option> is used, this option is
          implied. The argument is a positive integer or
          <literal>all</literal> to disable line limiting. The default
          value is 10 if no argument is given.</para></listitem>
        </varlistentry>

        <varlistentry>
          <term><option>--no-tail</option></term>

          <listitem><para>Show all stored output lines, even in follow
          mode. Undoes the effect of <option>--lines=</option>.
          </para></listitem>
        </varlistentry>

        <varlistentry>
          <term><option>-r</option></term>
          <term><option>--reverse</option></term>

          <listitem><para>Reverse output so that the newest entries
          are displayed first.</para></listitem>
        </varlistentry>

        <varlistentry>
          <term><option>-o</option></term>
          <term><option>--output=</option></term>

          <listitem><para>Controls the formatting of the journal
          entries that are shown. Takes one of the following
          options:</para>
          <variablelist>
            <varlistentry>
              <term>
                <option>short</option>
              </term>
              <listitem>
                <para>is the default and generates an output that is
                mostly identical to the formatting of classic syslog
                files, showing one line per journal entry.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>
                <option>short-iso</option>
              </term>
              <listitem>
                <para>is very similar, but shows ISO 8601 wallclock
                timestamps.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>
                <option>short-precise</option>
              </term>
              <listitem>
                <para>is very similar, but shows timestamps with full
                microsecond precision.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>
                <option>short-monotonic</option>
              </term>
              <listitem>
                <para>is very similar, but shows monotonic timestamps
                instead of wallclock timestamps.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>
                <option>verbose</option>
              </term>
              <listitem>
                <para>shows the full-structured entry items with all
                fields.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>
                <option>export</option>
              </term>
              <listitem>
                <para>serializes the journal into a binary (but mostly
                text-based) stream suitable for backups and network
                transfer (see
                <ulink url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal Export Format</ulink>
                for more information).</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>
                <option>json</option>
              </term>
              <listitem>
                <para>formats entries as JSON data structures, one per
                line (see
                <ulink url="http://www.freedesktop.org/wiki/Software/systemd/json">Journal JSON Format</ulink>
                for more information).</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>
                <option>json-pretty</option>
              </term>
              <listitem>
                <para>formats entries as JSON data structures, but
                formats them in multiple lines in order to make them
                more readable by humans.</para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>
                <option>json-sse</option>
              </term>
              <listitem>
                <para>formats entries as JSON data structures, but wraps
                them in a format suitable for
                <ulink url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent Events</ulink>.
                </para>
              </listitem>
            </varlistentry>

            <varlistentry>
              <term>
                <option>cat</option>
              </term>
              <listitem>
                <para>generates a very terse output, only showing the
                actual message of each journal entry with no metadata,
                not even a timestamp.</para>
              </listitem>
            </varlistentry>
          </variablelist>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--utc</option></term>

        <listitem><para>Express time in Coordinated Universal Time
        (UTC).</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-x</option></term>
        <term><option>--catalog</option></term>

        <listitem><para>Augment log lines with explanation texts from
        the message catalog. This will add explanatory help texts to
        log messages in the output where this is available. These
        short help texts will explain the context of an error or log
        event, possible solutions, as well as pointers to support
        forums, developer documentation, and any other relevant
        manuals. Note that help texts are not available for all
        messages, but only for selected ones. For more information on
        the message catalog, please refer to the
        <ulink url="http://www.freedesktop.org/wiki/Software/systemd/catalog">Message Catalog Developer Documentation</ulink>.</para>

        <para>Note: when attaching <command>journalctl</command>
        output to bug reports, please do <emphasis>not</emphasis> use
        <option>-x</option>.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-q</option></term>
        <term><option>--quiet</option></term>

        <listitem><para>Suppresses all info messages
        (i.e. "-- Logs begin at ...", "-- Reboot --"),
        any warning messages regarding
        inaccessible system journals when run as a normal
        user.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-m</option></term>
        <term><option>--merge</option></term>

        <listitem><para>Show entries interleaved from all available
        journals, including remote ones.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-b <optional><replaceable>ID</replaceable></optional><optional><replaceable>±offset</replaceable></optional></option></term>
        <term><option>--boot=<optional><replaceable>ID</replaceable></optional><optional><replaceable>±offset</replaceable></optional></option></term>

        <listitem><para>Show messages from a specific boot. This will
        add a match for <literal>_BOOT_ID=</literal>.</para>

        <para>The argument may be empty, in which case logs for the
        current boot will be shown.</para>

        <para>If the boot ID is omitted, a positive
        <replaceable>offset</replaceable> will look up the boots
        starting from the beginning of the journal, and an
        equal-or-less-than zero <replaceable>offset</replaceable> will
        look up boots starting from the end of the journal. Thus,
        <constant>1</constant> means the first boot found in the
        journal in chronological order, <constant>2</constant> the
        second and so on; while <constant>-0</constant> is the last
        boot, <constant>-1</constant> the boot before last, and so
        on. An empty <replaceable>offset</replaceable> is equivalent
        to specifying <constant>-0</constant>, except when the current
        boot is not the last boot (e.g. because
        <option>--directory</option> was specified to look at logs
        from a different machine).</para>

        <para>If the 32-character <replaceable>ID</replaceable> is
        specified, it may optionally be followed by
        <replaceable>offset</replaceable> which identifies the boot
        relative to the one given by boot
        <replaceable>ID</replaceable>. Negative values mean earlier
        boots and positive values mean later boots. If
        <replaceable>offset</replaceable> is not specified, a value of
        zero is assumed, and the logs for the boot given by
        <replaceable>ID</replaceable> are shown.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--list-boots</option></term>

        <listitem><para>Show a tabular list of boot numbers (relative to
        the current boot), their IDs, and the timestamps of the first
        and last message pertaining to the boot.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-k</option></term>
        <term><option>--dmesg</option></term>

        <listitem><para>Show only kernel messages. This implies
        <option>-b</option> and adds the match
        <literal>_TRANSPORT=kernel</literal>.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-t</option></term>
        <term><option>--identifier=<replaceable>SYSLOG_IDENTIFIER</replaceable></option></term>

        <listitem><para>Show messages for the specified syslog
        identifier
        <replaceable>SYSLOG_IDENTIFIER</replaceable>.</para>

        <para>This parameter can be specified multiple
        times.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-u</option></term>
        <term><option>--unit=<replaceable>UNIT</replaceable>|<replaceable>PATTERN</replaceable></option></term>

        <listitem><para>Show messages for the specified systemd unit
        <replaceable>UNIT</replaceable> (such as a service unit), or
        for any of the units matched by
        <replaceable>PATTERN</replaceable>.  If a pattern is
        specified, a list of unit names found in the journal is
        compared with the specified pattern and all that match are
        used. For each unit name, a match is added for messages from
        the unit
        (<literal>_SYSTEMD_UNIT=<replaceable>UNIT</replaceable></literal>),
        along with additional matches for messages from systemd and
        messages about coredumps for the specified unit.</para>

        <para>This parameter can be specified multiple times.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--user-unit=</option></term>

        <listitem><para>Show messages for the specified user session
        unit. This will add a match for messages from the unit
        (<literal>_SYSTEMD_USER_UNIT=</literal> and
        <literal>_UID=</literal>) and additional matches for messages
        from session systemd and messages about coredumps for the
        specified unit.</para>

        <para>This parameter can be specified multiple times.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-p</option></term>
        <term><option>--priority=</option></term>

        <listitem><para>Filter output by message priorities or
        priority ranges. Takes either a single numeric or textual log
        level (i.e. between 0/<literal>emerg</literal> and
        7/<literal>debug</literal>), or a range of numeric/text log
        levels in the form FROM..TO. The log levels are the usual
        syslog log levels as documented in
        <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
        i.e. <literal>emerg</literal> (0),
        <literal>alert</literal> (1), <literal>crit</literal> (2),
        <literal>err</literal> (3), <literal>warning</literal> (4),
        <literal>notice</literal> (5), <literal>info</literal> (6),
        <literal>debug</literal> (7). If a single log level is
        specified, all messages with this log level or a lower (hence
        more important) log level are shown. If a range is specified,
        all messages within the range are shown, including both the
        start and the end value of the range. This will add
        <literal>PRIORITY=</literal> matches for the specified
        priorities.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-c</option></term>
        <term><option>--cursor=</option></term>

        <listitem><para>Start showing entries from the location in the
        journal specified by the passed cursor.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--after-cursor=</option></term>

        <listitem><para>Start showing entries from the location in the
        journal <emphasis>after</emphasis> the location specified by
        the passed cursor.  The cursor is shown when the
        <option>--show-cursor</option> option is used.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--show-cursor</option></term>

        <listitem><para>The cursor is shown after the last entry after
        two dashes:</para>
        <programlisting>-- cursor: s=0639...</programlisting>
        <para>The format of the cursor is private
        and subject to change.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-S</option></term>
        <term><option>--since=</option></term>
        <term><option>-U</option></term>
        <term><option>--until=</option></term>

        <listitem><para>Start showing entries on or newer than the
        specified date, or on or older than the specified date,
        respectively. Date specifications should be of the format
        <literal>2012-10-30 18:17:16</literal>.  If the time part is
        omitted, <literal>00:00:00</literal> is assumed.  If only the
        seconds component is omitted, <literal>:00</literal> is
        assumed. If the date component is omitted, the current day is
        assumed. Alternatively the strings
        <literal>yesterday</literal>, <literal>today</literal>,
        <literal>tomorrow</literal> are understood, which refer to
        00:00:00 of the day before the current day, the current day,
        or the day after the current day,
        respectively. <literal>now</literal> refers to the current
        time. Finally, relative times may be specified, prefixed with
        <literal>-</literal> or <literal>+</literal>, referring to
        times before or after the current time, respectively. For complete
        time and date specification, see
        <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
        </para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-F</option></term>
        <term><option>--field=</option></term>

        <listitem><para>Print all possible data values the specified
        field can take in all entries of the journal.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-N</option></term>
        <term><option>--fields</option></term>

        <listitem><para>Print all field names currently used in all entries of the journal.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--system</option></term>
        <term><option>--user</option></term>

        <listitem><para>Show messages from system services and the
        kernel (with <option>--system</option>). Show messages from
        service of current user (with <option>--user</option>).  If
        neither is specified, show all messages that the user can see.
        </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-M</option></term>
        <term><option>--machine=</option></term>

        <listitem><para>Show messages from a running, local
        container. Specify a container name to connect to.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>-D <replaceable>DIR</replaceable></option></term>
        <term><option>--directory=<replaceable>DIR</replaceable></option></term>

        <listitem><para>Takes a directory path as argument. If
        specified, journalctl will operate on the specified journal
        directory <replaceable>DIR</replaceable> instead of the
        default runtime and system journal paths.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--file=<replaceable>GLOB</replaceable></option></term>

        <listitem><para>Takes a file glob as an argument. If
        specified, journalctl will operate on the specified journal
        files matching <replaceable>GLOB</replaceable> instead of the
        default runtime and system journal paths. May be specified
        multiple times, in which case files will be suitably
        interleaved.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--root=<replaceable>ROOT</replaceable></option></term>

        <listitem><para>Takes a directory path as an argument. If
        specified, journalctl will operate on catalog file hierarchy
        underneath the specified directory instead of the root
        directory (e.g. <option>--update-catalog</option> will create
        <filename><replaceable>ROOT</replaceable>/var/lib/systemd/catalog/database</filename>).
        </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--new-id128</option></term>

        <listitem><para>Instead of showing journal contents, generate
        a new 128-bit ID suitable for identifying messages. This is
        intended for usage by developers who need a new identifier for
        a new message they introduce and want to make
        recognizable. This will print the new ID in three different
        formats which can be copied into source code or similar.
        </para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--header</option></term>

        <listitem><para>Instead of showing journal contents, show
        internal header information of the journal fields
        accessed.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--disk-usage</option></term>

        <listitem><para>Shows the current disk usage of all journal
        files. This shows the sum of the disk usage of all archived
        and active journal files.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--vacuum-size=</option></term>
        <term><option>--vacuum-time=</option></term>
        <term><option>--vacuum-files=</option></term>

        <listitem><para>Removes archived journal files until the disk
        space they use falls below the specified size (specified with
        the usual <literal>K</literal>, <literal>M</literal>,
        <literal>G</literal> and <literal>T</literal> suffixes), or all
        journal files contain no data older than the specified
        timespan (specified with the usual <literal>s</literal>,
        <literal>min</literal>, <literal>h</literal>,
        <literal>days</literal>, <literal>months</literal>,
        <literal>weeks</literal> and <literal>years</literal> suffixes),
        or no more than the specified number of separate journal files
        remain. Note that running <option>--vacuum-size=</option> has
        only an indirect effect on the output shown by
        <option>--disk-usage</option>, as the latter includes active
        journal files, while the vacuuming operation only operates
        on archived journal files. Similarly,
        <option>--vacuum-files=</option> might not actually reduce the
        number of journal files to below the specified number, as it
        will not remove active journal
        files. <option>--vacuum-size=</option>,
        <option>--vacuum-time=</option> and
        <option>--vacuum-files=</option> may be combined in a single
        invocation to enforce any combination of a size, a time and a
        number of files limit on the archived journal
        files. Specifying any of these three parameters as zero is
        equivalent to not enforcing the specific limit, and is thus
        redundant.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--list-catalog
        <optional><replaceable>128-bit-ID...</replaceable></optional>
        </option></term>

        <listitem><para>List the contents of the message catalog as a
        table of message IDs, plus their short description strings.
        </para>

        <para>If any <replaceable>128-bit-ID</replaceable>s are
        specified, only those entries are shown.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--dump-catalog
        <optional><replaceable>128-bit-ID...</replaceable></optional>
        </option></term>

        <listitem><para>Show the contents of the message catalog, with
        entries separated by a line consisting of two dashes and the
        ID (the format is the same as <filename>.catalog</filename>
        files).</para>

        <para>If any <replaceable>128-bit-ID</replaceable>s are
        specified, only those entries are shown.</para>
        </listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--update-catalog</option></term>

        <listitem><para>Update the message catalog index. This command
        needs to be executed each time new catalog files are
        installed, removed, or updated to rebuild the binary catalog
        index.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--setup-keys</option></term>

        <listitem><para>Instead of showing journal contents, generate
        a new key pair for Forward Secure Sealing (FSS). This will
        generate a sealing key and a verification key. The sealing key
        is stored in the journal data directory and shall remain on
        the host. The verification key should be stored
        externally. Refer to the <option>Seal=</option> option in
        <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
        for information on Forward Secure Sealing and for a link to a
        refereed scholarly paper detailing the cryptographic theory it
        is based on.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--force</option></term>

        <listitem><para>When <option>--setup-keys</option> is passed
        and Forward Secure Sealing (FSS) has already been configured,
        recreate FSS keys.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--interval=</option></term>

        <listitem><para>Specifies the change interval for the sealing
        key when generating an FSS key pair with
        <option>--setup-keys</option>. Shorter intervals increase CPU
        consumption but shorten the time range of undetectable journal
        alterations. Defaults to 15min.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--verify</option></term>

        <listitem><para>Check the journal file for internal
        consistency. If the file has been generated with FSS enabled and
        the FSS verification key has been specified with
        <option>--verify-key=</option>, authenticity of the journal file
        is verified.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--verify-key=</option></term>

        <listitem><para>Specifies the FSS verification key to use for
        the <option>--verify</option> operation.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--sync</option></term>

        <listitem><para>Asks the journal daemon to write all yet
        unwritten journal data to the backing file system and
        synchronize all journals. This call does not return until the
        synchronization operation is complete. This command guarantees
        that any log messages written before its invocation are safely
        stored on disk at the time it returns.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--flush</option></term>

        <listitem><para>Asks the journal daemon to flush any log data
        stored in <filename>/run/log/journal</filename> into
        <filename>/var/log/journal</filename>, if persistent storage
        is enabled. This call does not return until the operation is
        complete. Note that this call is idempotent: the data is only
        flushed from <filename>/run/log/journal</filename> into
        <filename>/var/log/journal</filename> once during system
        runtime, and this command exits cleanly without executing any
        operation if this has already has happened. This command
        effectively guarantees that all data is flushed to
        <filename>/var/log/journal</filename> at the time it
        returns.</para></listitem>
      </varlistentry>

      <varlistentry>
        <term><option>--rotate</option></term>

        <listitem><para>Asks the journal daemon to rotate journal
        files. This call does not return until the rotation operation
        is complete.</para></listitem>
      </varlistentry>

      <xi:include href="standard-options.xml" xpointer="help" />
      <xi:include href="standard-options.xml" xpointer="version" />
      <xi:include href="standard-options.xml" xpointer="no-pager" />
    </variablelist>
  </refsect1>

  <refsect1>
    <title>Exit status</title>

    <para>On success, 0 is returned; otherwise, a non-zero failure
    code is returned.</para>
  </refsect1>

  <xi:include href="less-variables.xml" />

  <refsect1>
    <title>Examples</title>

    <para>Without arguments, all collected logs are shown
    unfiltered:</para>

    <programlisting>journalctl</programlisting>

    <para>With one match specified, all entries with a field matching
    the expression are shown:</para>

    <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>

    <para>If two different fields are matched, only entries matching
    both expressions at the same time are shown:</para>

    <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>

    <para>If two matches refer to the same field, all entries matching
    either expression are shown:</para>

    <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>

    <para>If the separator <literal>+</literal> is used, two
    expressions may be combined in a logical OR. The following will
    show all messages from the Avahi service process with the PID
    28097 plus all messages from the D-Bus service (from any of its
    processes):</para>

    <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>

    <para>Show all logs generated by the D-Bus executable:</para>

    <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>

    <para>Show all kernel logs from previous boot:</para>

    <programlisting>journalctl -k -b -1</programlisting>

    <para>Show a live log display from a system service
    <filename>apache.service</filename>:</para>

    <programlisting>journalctl -f -u apache</programlisting>

  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>coredumpctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
      <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>
    </para>
  </refsect1>
</refentry>