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
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
|
<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
<refentry id="journalctl"
xmlns:xi="http://www.w3.org/2001/XInclude">
<refentryinfo>
<title>journalctl</title>
<productname>systemd</productname>
</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>It is also possible to filter the entries by specifying an
absolute file path as an argument. The file path may be a file or
a symbolic link and the file must exist at the time of the query. If a
file path refers to an executable binary, an <literal>_EXE=</literal>
match for the canonicalized binary path is added to the query. If a
file path refers to an executable script, a <literal>_COMM=</literal>
match for the script name is added to the query. If a file path
refers to a device node, <literal>_KERNEL_DEVICE=</literal> matches for
the kernel name of the device and for each of its ancestor devices is
added to the query. Symbolic links are dereferenced, kernel names are
synthesized, and parent devices are identified from the environment at
the time of the query. In general, a device node is the best proxy for
an actual device, as log entries do not usually contain fields that
identify an actual device. For the resulting log entries to be correct
for the actual device, the relevant parts of the environment at the time
the entry was logged, in particular the actual device corresponding to
the device node, must have been the same as those at the time of the
query. Because device nodes generally change their corresponding devices
across reboots, specifying a device node path causes the resulting
entries to be restricted to those from the current boot.</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; lines of level DEBUG
are colored lighter grey; 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. By
default, fields with unprintable characters are abbreviated as "blob data". (Note that the pager may escape
unprintable characters again.)</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-full</option>
</term>
<listitem>
<para>is very similar, but shows timestamps in the format the <option>--since=</option> and
<option>--until=</option> options accept. Unlike the timestamp information shown in
<option>short</option> output mode this mode includes weekday, year and timezone information in the
output, and is locale-independent.</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-iso-precise</option>
</term>
<listitem>
<para>as for <option>short-iso</option> but includes full
microsecond precision.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>short-precise</option>
</term>
<listitem>
<para>is very similar, but shows classic syslog 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>short-unix</option>
</term>
<listitem>
<para>is very similar, but shows seconds passed since January 1st 1970 UTC instead of wallclock
timestamps ("UNIX time"). The time is shown with microsecond accuracy.</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="https://www.freedesktop.org/wiki/Software/systemd/export">Journal Export Format</ulink>
for more information). To import the binary stream back
into native journald format use
<citerefentry><refentrytitle>systemd-journal-remote</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>json</option>
</term>
<listitem>
<para>formats entries as JSON objects, separated by newline characters (see <ulink
url="https://www.freedesktop.org/wiki/Software/systemd/json">Journal JSON Format</ulink> for more
information). Field values are generally encoded as JSON strings, with three exceptions:
<orderedlist>
<listitem><para>Fields larger than 4096 bytes are encoded as <constant>null</constant> values. (This
may be turned off by passing <option>--all</option>, but be aware that this may allocate overly long
JSON objects.) </para></listitem>
<listitem><para>Journal entries permit non-unique fields within the same log entry. JSON does not allow
non-unique fields within objects. Due to this, if a non-unique field is encountered a JSON array is
used as field value, listing all field values as elements.</para></listitem>
<listitem><para>Fields containing non-printable or non-UTF8 bytes are encoded as arrays containing
the raw bytes individually formatted as unsigned numbers.</para></listitem>
</orderedlist>
Note that this encoding is reversible (with the exception of the size limit).</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>json-seq</option>
</term>
<listitem>
<para>formats entries as JSON data structures, but prefixes them with an ASCII Record Separator
character (0x1E) and suffixes them with an ASCII Line Feed character (0x0A), in accordance with <ulink
url="https://tools.ietf.org/html/rfc7464">JavaScript Object Notation (JSON) Text Sequences </ulink>
(<literal>application/json-seq</literal>).
</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. If combined with the
<option>--output-fields=</option> option will output the listed fields for each log record,
instead of the message.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>with-unit</option>
</term>
<listitem>
<para>similar to short-full, but prefixes the unit and
user unit names instead of the traditional syslog
identifier. Useful when using templated instances, as it
will include the arguments in the unit names.</para>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--output-fields=</option></term>
<listitem><para>A comma separated list of the fields which should be included in the output. This has
an effect only for the output modes which would normally show all fields (<option>verbose</option>,
<option>export</option>, <option>json</option>, <option>json-pretty</option>,
<option>json-sse</option> and <option>json-seq</option>), as well as on <option>cat</option>. For the
former, the <literal>__CURSOR</literal>, <literal>__REALTIME_TIMESTAMP</literal>,
<literal>__MONOTONIC_TIMESTAMP</literal>, and <literal>_BOOT_ID</literal> fields are always
printed.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--utc</option></term>
<listitem><para>Express time in Coordinated Universal Time
(UTC).</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--no-hostname</option></term>
<listitem><para>Don't show the hostname field of log messages originating from the local host. This
switch has an effect only on the <option>short</option> family of output modes (see above).
</para>
<para>Note: this option does not remove occurrences of the hostname from log entries themselves, so
it does not prevent the hostname from being visible in the logs.</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="https://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 informational messages
(i.e. "-- Journal begins 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><optional><replaceable>ID</replaceable></optional><optional><replaceable>±offset</replaceable></optional>|<constant>all</constant></optional></option></term>
<term><option>--boot<optional>=<optional><replaceable>ID</replaceable></optional><optional><replaceable>±offset</replaceable></optional>|<constant>all</constant></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>
<para>The special argument <constant>all</constant> can be
used to negate the effect of an earlier use of
<option>-b</option>.</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. A match
is also added for <literal>_SYSTEMD_SLICE=<replaceable>UNIT</replaceable></literal>,
such that if the provided <replaceable>UNIT</replaceable> is a
<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>
unit, all logs of children of the slice will be shown.
</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. A match
is also added for <literal>_SYSTEMD_USER_SLICE=<replaceable>UNIT</replaceable></literal>,
such that if the provided <replaceable>UNIT</replaceable> is a
<citerefentry><refentrytitle>systemd.slice</refentrytitle><manvolnum>5</manvolnum></citerefentry>
unit, all logs of children of the unit will be shown.</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>--facility=</option></term>
<listitem><para>Filter output by syslog facility. Takes a comma-separated list of numbers or facility
names. The names are the usual syslog facilities as documented in
<citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
<option>--facility=help</option> may be used to display a list of known facility names and exit.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-g</option></term>
<term><option>--grep=</option></term>
<listitem><para>Filter output to entries where the <varname>MESSAGE=</varname>
field matches the specified regular expression. PERL-compatible regular expressions
are used, see
<citerefentry project='url'><refentrytitle url='http://pcre.org/current/doc/html/pcre2pattern.html'>pcre2pattern</refentrytitle><manvolnum>3</manvolnum></citerefentry>
for a detailed description of the syntax.</para>
<para>If the pattern is all lowercase, matching is case insensitive.
Otherwise, matching is case sensitive. This can be overridden with the
<option>--case-sensitive</option> option, see below.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--case-sensitive<optional>=BOOLEAN</optional></option></term>
<listitem><para>Make pattern matching case sensitive or case insensitive.</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>--cursor-file=<replaceable>FILE</replaceable></option></term>
<listitem><para>If <replaceable>FILE</replaceable> exists and contains a
cursor, start showing entries <emphasis>after</emphasis> this location.
Otherwise the show entries according the other given options. At the end,
write the cursor of the last entry to <replaceable>FILE</replaceable>. Use
this option to continually read the journal by sequentially calling
<command>journalctl</command>.</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>. Note that
<option>--output=short-full</option> prints timestamps that follow precisely this format.
</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, <command>journalctl</command>
will operate on journal directories and 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>, and journal
files under <filename><replaceable>ROOT</replaceable>/run/journal/</filename> or
<filename><replaceable>ROOT</replaceable>/var/log/journal/</filename> will be displayed).
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--image=<replaceable>IMAGE</replaceable></option></term>
<listitem><para>Takes a path to a disk image file or block device node. If specified,
<command>journalctl</command> will operate on the file system in the indicated disk image. This is
similar to <option>--root=</option> but operates on file systems stored in disk images or block
devices, thus providing an easy way to extract log data from disk images. The disk image should
either contain just a file system or a set of file systems within a GPT partition table, following
the <ulink url="https://systemd.io/DISCOVERABLE_PARTITIONS">Discoverable Partitions
Specification</ulink>. For further information on supported disk images, see
<citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
switch of the same name.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--namespace=<replaceable>NAMESPACE</replaceable></option></term>
<listitem><para>Takes a journal namespace identifier string as argument. If not specified the data
collected by the default namespace is shown. If specified shows the log data of the specified
namespace instead. If the namespace is specified as <literal>*</literal> data from all namespaces is
shown, interleaved. If the namespace identifier is prefixed with <literal>+</literal> data from the
specified namespace and the default namespace is shown, interleaved, but no other. For details about
journal namespaces see
<citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</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 the oldest 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 archived journal files contain no data older than the specified timespan
(specified with the usual <literal>s</literal>, <literal>m</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.</para>
<para><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>
<para>These three switches may also be combined with <option>--rotate</option> into one command. If so, all
active files are rotated first, and the requested vacuuming operation is executed right after. The rotation has
the effect that all currently active files are archived (and potentially new, empty journal files opened as
replacement), and hence the vacuuming operation has the greatest effect as it can take all log data written so
far into account.</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 (but see
<option>--relinquish-var</option> below), and this command exits cleanly without executing any
operation if this has already 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>--relinquish-var</option></term>
<listitem><para>Asks the journal daemon for the reverse operation to <option>--flush</option>: if
requested the daemon will write further log data to <filename>/run/log/journal/</filename> and stops
writing to <filename>/var/log/journal/</filename>. A subsequent call to <option>--flush</option>
causes the log output to switch back to <filename>/var/log/journal/</filename>, see
above.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--smart-relinquish-var</option></term>
<listitem><para>Similar to <option>--relinquish-var</option> but executes no operation if the root file
system and <filename>/var/lib/journal/</filename> reside on the same mount point. This operation is
used during system shutdown in order to make the journal daemon stop writing data to
<filename>/var/log/journal/</filename> in case that directory is located on a mount point that needs
to be unmounted.</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. Journal file rotation has the effect that all currently active journal files are marked
as archived and renamed, so that they are never written to in future. New (empty) journal files are then
created in their place. This operation may be combined with <option>--vacuum-size=</option>,
<option>--vacuum-time=</option> and <option>--vacuum-file=</option> into a single command, see
above.</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
journalctl _SYSTEMD_CGROUP=/user.slice/user-42.slice/session-c1.scope</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>To show all fields emitted <emphasis>by</emphasis> a unit and <emphasis>about</emphasis>
the unit, option <option>-u</option>/<option>--unit=</option> should be used.
<command>journalctl -u <replaceable>name</replaceable></command>
expands to a complex filter similar to
<programlisting>_SYSTEMD_UNIT=<replaceable>name</replaceable>.service
+ UNIT=<replaceable>name</replaceable>.service _PID=1
+ OBJECT_SYSTEMD_UNIT=<replaceable>name</replaceable>.service _UID=0
+ COREDUMP_UNIT=<replaceable>name</replaceable>.service _UID=0 MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1
</programlisting>
(see <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
for an explanation of those patterns).
</para>
<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>,
<citerefentry><refentrytitle>systemd-journal-remote.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-journal-upload.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
|