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6 This file is part of systemd.
8 Copyright 2012 Lennart Poettering
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24 <refentry id="journalctl">
27 <title>journalctl</title>
28 <productname>systemd</productname>
32 <contrib>Developer</contrib>
33 <firstname>Lennart</firstname>
34 <surname>Poettering</surname>
35 <email>lennart@poettering.net</email>
41 <refentrytitle>journalctl</refentrytitle>
42 <manvolnum>1</manvolnum>
46 <refname>journalctl</refname>
47 <refpurpose>Query the systemd journal</refpurpose>
52 <command>journalctl</command>
53 <arg choice="opt" rep="repeat">OPTIONS</arg>
54 <arg choice="opt" rep="repeat">MATCHES</arg>
59 <title>Description</title>
61 <para><command>journalctl</command> may be used to
62 query the contents of the
63 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
65 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
67 <para>If called without parameters, it will show the full
68 contents of the journal, starting with the oldest
69 entry collected.</para>
71 <para>If one or more match arguments are passed, the
72 output is filtered accordingly. A match is in the
73 format <literal>FIELD=VALUE</literal>,
74 e.g. <literal>_SYSTEMD_UNIT=httpd.service</literal>,
75 referring to the components of a structured journal
77 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
78 for a list of well-known fields. If multiple matches
79 are specified matching different fields, the log
80 entries are filtered by both, i.e. the resulting output
81 will show only entries matching all the specified
82 matches of this kind. If two matches apply to the same
83 field, then they are automatically matched as
84 alternatives, i.e. the resulting output will show
85 entries matching any of the specified matches for the
86 same field. Finally, if the character
87 <literal>+</literal> appears as separate word on the
88 command line, all matches before and after are combined
89 in a disjunction (i.e. logical OR).</para>
91 <para>As shortcuts for a few types of field/value
92 matches, file paths may be specified. If a file path
93 refers to an executable file, this is equivalent to an
94 <literal>_EXE=</literal> match for the canonicalized
95 binary path. Similarly, if a path refers to a device
96 node, this is equivalent to a
97 <literal>_KERNEL_DEVICE=</literal> match for the
100 <para>Output is interleaved from all accessible
101 journal files, whether they are rotated or currently
102 being written, and regardless of whether they belong to the
103 system itself or are accessible user journals.</para>
105 <para>All users are granted access to their private
106 per-user journals. However, by default, only root and
107 users who are members of the <literal>adm</literal>
108 group get access to the system journal and the
109 journals of other users.</para>
111 <para>The output is paged through
112 <command>less</command> by default, and long lines are
113 "truncated" to screen width. The hidden part can be
114 viewed by using the left-arrow and right-arrow
115 keys. Paging can be disabled, see
116 <option>--no-pager</option> and section Environment
119 <para>When outputing to a tty, lines are colored
120 according to priority: lines of level ERROR and higher
121 are colored red, lines of level NOTICE and higher are
122 highlighted, and other lines are displayed normally.
127 <title>Options</title>
129 <para>The following options are understood:</para>
133 <term><option>-h</option></term>
134 <term><option>--help</option></term>
136 <listitem><para>Prints a short help
137 text and exits.</para></listitem>
141 <term><option>--version</option></term>
143 <listitem><para>Prints a short version
144 string and exits.</para></listitem>
148 <term><option>--no-pager</option></term>
150 <listitem><para>Do not pipe output into a
151 pager.</para></listitem>
155 <term><option>-l</option></term>
156 <term><option>--full</option></term>
158 <listitem><para>Show all (printable) fields in
159 full.</para></listitem>
163 <term><option>-a</option></term>
164 <term><option>--all</option></term>
166 <listitem><para>Show all fields in
167 full, even if they include unprintable
168 characters or are very
169 long.</para></listitem>
173 <term><option>-f</option></term>
174 <term><option>--follow</option></term>
176 <listitem><para>Show only the most recent
177 journal entries, and continuously print
178 new entries as they are appended to
179 the journal.</para></listitem>
183 <term><option>-e</option></term>
184 <term><option>--pager-end</option></term>
186 <listitem><para>Immediately jump to
187 the end of the journal inside the
188 implied pager tool. This implies
189 <option>-n1000</option> to guarantee
190 that the pager will not buffer logs of
191 unbounded size. This may be overridden
192 with an explicit <option>-n</option>
193 with some other numeric value on the
194 command line. Note that this option is
195 only supported for the
196 <citerefentry><refentrytitle>less</refentrytitle><manvolnum>1</manvolnum></citerefentry>
197 pager.</para></listitem>
201 <term><option>-n</option></term>
202 <term><option>--lines=</option></term>
204 <listitem><para>Show the most recent
205 journal events and limit the number of
207 <option>--follow</option> is used,
208 this option is implied. The argument,
209 a positive integer, is optional, and
210 defaults to 10. </para></listitem>
214 <term><option>--no-tail</option></term>
216 <listitem><para>Show all stored output
217 lines, even in follow mode. Undoes the
219 <option>--lines=</option>.</para></listitem>
223 <term><option>-r</option></term>
224 <term><option>--reverse</option></term>
226 <listitem><para>Reverse output, so the newest
227 entries are displayed first.</para></listitem>
231 <term><option>-o</option></term>
232 <term><option>--output=</option></term>
234 <listitem><para>Controls the
235 formatting of the journal entries that
236 are shown. Takes one of the following options:
241 <option>short</option>
245 and generates an output
246 that is mostly identical
248 classic syslog files,
250 journal entry.</para>
256 <option>short-monotonic</option>
259 <para>is very similar
261 timestamps instead of
262 wallclock timestamps.
269 <option>verbose</option>
273 full-structured entry
274 items with all fields.
281 <option>export</option>
285 journal into a binary
286 (but mostly text-based)
290 url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal
291 Export Format</ulink>
299 <option>json</option>
302 <para>formats entries
303 as JSON data structures,
304 one per line (see <ulink
305 url="http://www.freedesktop.org/wiki/Software/systemd/json">Journal
306 JSON Format</ulink> for
307 more information).</para>
313 <option>json-pretty</option>
316 <para>formats entries as
317 JSON data structures,
319 multiple lines in order
321 readable for humans.</para>
327 <option>json-sse</option>
330 <para>formats entries as
331 JSON data structures,
333 format suitable for <ulink
334 url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent
335 Events</ulink>.</para>
344 <para>generates a very
347 message of each journal
348 entry with no meta data,
349 not even a timestamp.
358 <term><option>-x</option></term>
359 <term><option>--catalog</option></term>
361 <listitem><para>Augment log lines with
362 explanation texts from the message
363 catalog. This will add explanatory
364 help texts to log messages in the
365 output where this is available. These
366 short help texts will explain the
367 context of an error or log event,
368 possible solutions, as well as
369 pointers to support forums, developer
370 documentation and any other relevant
371 manuals. Note that help texts are not
372 available for all messages, but only
373 for selected ones. For more
374 information on the message catalog,
375 please refer to the <ulink
376 url="http://www.freedesktop.org/wiki/Software/systemd/catalog">Message
378 Documentation</ulink>.</para></listitem>
382 <term><option>-q</option></term>
383 <term><option>--quiet</option></term>
385 <listitem><para>Suppresses any warning
386 message regarding inaccessible system
387 journals when run as normal
388 user.</para></listitem>
392 <term><option>-m</option></term>
393 <term><option>--merge</option></term>
395 <listitem><para>Show entries
396 interleaved from all available
397 journals, including remote
398 ones.</para></listitem>
402 <term><option>-b <optional><replaceable>ID</replaceable></optional></option></term>
403 <term><option>--boot=<optional><replaceable>ID</replaceable></optional></option></term>
405 <listitem><para>Show messages from the specified
406 boot <replaceable>ID</replaceable> or from
407 current boot if no <replaceable>ID</replaceable>
408 is given. This will add a match for
409 <literal>_BOOT_ID=</literal>.</para>
411 <para>The argument is a 128 bit ID given in
412 short or UUID form and optionally followed by
413 <literal>:n</literal> which identifies the nth
414 boot relative to the boot ID given to the left
415 of <literal>:</literal>. Supplying a negative
416 value for n will look for a past boot and a
417 positive value for a future boot. The boot IDs
418 are searched for in chronological order. If no
419 number is provided after <literal>:</literal>,
420 <literal>-1</literal> is assumed. A value of 0
421 is valid and equivalent to omitting
422 <literal>:0</literal>.</para>
424 <para>Alternatively, the argument may constist
425 only of <literal>:n</literal>. In this case, a
426 positive value will look up the nth boot
427 starting from the beginning of the jouranl, a
428 negative value will look up a previous boot
429 relative to the current boot. <literal>:0</literal>
430 will look for the current boot ID. Thus,
431 <literal>:1</literal> is the first boot found in
432 the journal, <literal>:2</literal> the second
433 and so on; while <literal>:-1</literal> is the
434 previous boot, <literal>:-2</literal> the boot
435 before that and so on. Omitting a value after
436 <literal>:</literal> will look for the previous
437 boot.</para></listitem>
441 <term><option>-k</option></term>
442 <term><option>--dmesg</option></term>
444 <listitem><para>Show only kernel messages. This
445 implies <option>-b</option> and adds the match
446 <literal>_TRANSPORT=kernel</literal>.
451 <term><option>-u</option></term>
452 <term><option>--unit=</option></term>
454 <listitem><para>Show messages for the
455 specified systemd unit. This will add
456 a match for messages from the unit
457 (<literal>_SYSTEMD_UNIT=</literal>)
458 and additional matches for messages
459 from systemd and messages about
460 coredumps for the specified unit.</para>
461 <para>This parameter can be specified multiple times.
466 <term><option>--user-unit=</option></term>
468 <listitem><para>Show messages for the
469 specified user session unit. This will
470 add a match for messages from the unit
471 (<literal>_SYSTEMD_USER_UNIT=</literal>
472 and <literal>_UID=</literal>) and
473 additional matches for messages from
474 session systemd and messages about
475 coredumps for the specified unit.</para>
476 <para>This parameter can be specified multiple times.
481 <term><option>-p</option></term>
482 <term><option>--priority=</option></term>
484 <listitem><para>Filter output by
485 message priorities or priority
486 ranges. Takes either a single numeric
487 or textual log level (i.e. between
488 0/<literal>emerg</literal> and
489 7/<literal>debug</literal>), or a
490 range of numeric/text log levels in
491 the form FROM..TO. The log levels are
492 the usual syslog log levels as
494 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
495 i.e. <literal>emerg</literal> (0),
496 <literal>alert</literal> (1),
497 <literal>crit</literal> (2),
498 <literal>err</literal> (3),
499 <literal>warning</literal> (4),
500 <literal>notice</literal> (5),
501 <literal>info</literal> (6),
502 <literal>debug</literal> (7). If a
503 single log level is specified, all
504 messages with this log level or a
505 lower (hence more important) log level
506 are shown. If a range is specified, all
507 messages within the range are shown,
508 including both the start and the end
509 value of the range. This will add
510 <literal>PRIORITY=</literal> matches
512 priorities.</para></listitem>
516 <term><option>-c</option></term>
517 <term><option>--cursor=</option></term>
519 <listitem><para>Start showing entries
520 from the location in the journal
521 specified by the passed
522 cursor.</para></listitem>
526 <term><option>--since=</option></term>
527 <term><option>--until=</option></term>
529 <listitem><para>Start showing entries
530 on or newer than the specified date,
531 or on or older than the specified
532 date, respectively. Date specifications
533 should be of the format
534 <literal>2012-10-30 18:17:16</literal>.
535 If the time part is omitted,
536 <literal>00:00:00</literal> is assumed.
537 If only the seconds component is omitted,
538 <literal>:00</literal> is assumed. If the
539 date component is omitted, the current
540 day is assumed. Alternatively the strings
541 <literal>yesterday</literal>,
542 <literal>today</literal>,
543 <literal>tomorrow</literal> are
544 understood, which refer to 00:00:00 of
545 the day before the current day, the
546 current day, or the day after the
547 current day, respectively. <literal>now</literal>
548 refers to the current time. Finally,
549 relative times may be specified,
550 prefixed with <literal>-</literal> or
551 <literal>+</literal>, referring to
552 times before or after the current
553 time, respectively.</para></listitem>
557 <term><option>-F</option></term>
558 <term><option>--field=</option></term>
560 <listitem><para>Print all possible
561 data values the specified field can
562 take in all entries of the
563 journal.</para></listitem>
567 <term><option>--system</option></term>
568 <term><option>--user</option></term>
570 <listitem><para>Show messages from
571 system services and the kernel (with
572 <option>--system</option>). Show
573 messages from service of current user
574 (with <option>--user</option>).
575 If neither is specified, show all
576 messages that the user can see.
581 <term><option>-D <replaceable>DIR</replaceable></option></term>
582 <term><option>--directory=<replaceable>DIR</replaceable></option></term>
584 <listitem><para>Takes a directory path
585 as argument. If specified, journalctl
586 will operate on the specified journal
588 <replaceable>DIR</replaceable> instead
589 of the default runtime and system
590 journal paths.</para></listitem>
594 <term><option>--file=<replaceable>GLOB</replaceable></option></term>
596 <listitem><para>Takes a file glob as
597 argument. If specified, journalctl will
598 operate on the specified journal files
599 matching <replaceable>GLOB</replaceable>
600 instead of the default runtime and
601 system journal paths. May be specified
602 multiple times, in which case files will
603 be suitably interleaved.</para></listitem>
607 <term><option>--root=<replaceable>ROOT</replaceable></option></term>
609 <listitem><para>Takes a directory path
610 as argument. If specified, journalctl
611 will operate on catalog file hierarchy
612 underneath the specified directory
613 instead of the root directory
614 (e.g. <option>--update-catalog</option>
616 <filename><replaceable>ROOT</replaceable>/var/lib/systemd/catalog/database</filename>).
621 <term><option>--new-id128</option></term>
623 <listitem><para>Instead of showing
624 journal contents, generate a new 128
625 bit ID suitable for identifying
626 messages. This is intended for usage
627 by developers who need a new
628 identifier for a new message they
629 introduce and want to make
630 recognizable. This will print the new ID in
631 three different formats which can be
632 copied into source code or
633 similar.</para></listitem>
637 <term><option>--header</option></term>
639 <listitem><para>Instead of showing
640 journal contents, show internal header
641 information of the journal fields
642 accessed.</para></listitem>
646 <term><option>--disk-usage</option></term>
648 <listitem><para>Shows the current disk
650 journal files.</para></listitem>
654 <term><option>--list-catalog
655 <optional><replaceable>ID128...</replaceable></optional>
658 <listitem><para>List the contents of
659 the message catalog, as table of
660 message IDs plus their short
661 description strings.</para>
664 <replaceable>ID128</replaceable>s are
665 specified, only those entries are shown.
671 <term><option>--dump-catalog
672 <optional><replaceable>ID128...</replaceable></optional>
675 <listitem><para>Show the contents of
676 the message catalog, with entries
677 separated by a line consisting of two
678 dashes and the id (the format is the
679 same as <filename>.catalog</filename>
683 <replaceable>ID128</replaceable>s are
684 specified, only those entries are shown.
690 <term><option>--update-catalog</option></term>
692 <listitem><para>Update the message
693 catalog index. This command needs to
694 be executed each time new catalog
695 files are installed, removed or
696 updated to rebuild the binary catalog
697 index.</para></listitem>
701 <term><option>--setup-keys</option></term>
703 <listitem><para>Instead of showing
704 journal contents, generate a new key
705 pair for Forward Secure Sealing
706 (FSS). This will generate a sealing
707 key and a verification key. The
708 sealing key is stored in the journal
709 data directory and shall remain on the
710 host. The verification key should be
711 stored externally. Also see the
712 <option>Seal=</option> option in
713 <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
714 for details.</para></listitem>
718 <term><option>--force</option></term>
720 <listitem><para>When --setup-keys is passed and
721 Forward Secure Sealing has already been set up,
722 recreate FSS keys.</para></listitem>
726 <term><option>--interval=</option></term>
728 <listitem><para>Specifies the change
729 interval for the sealing key when
730 generating an FSS key pair with
731 <option>--setup-keys</option>. Shorter
732 intervals increase CPU consumption but
733 shorten the time range of
735 alterations. Defaults to
736 15min.</para></listitem>
740 <term><option>--verify</option></term>
742 <listitem><para>Check the journal file
743 for internal consistency. If the
744 file has been generated with FSS
745 enabled and the FSS verification key
746 has been specified with
747 <option>--verify-key=</option>,
748 authenticity of the journal file is
749 verified.</para></listitem>
753 <term><option>--verify-key=</option></term>
755 <listitem><para>Specifies the FSS
756 verification key to use for the
757 <option>--verify</option>
758 operation.</para></listitem>
765 <title>Exit status</title>
767 <para>On success, 0 is returned, a non-zero failure
768 code otherwise.</para>
772 <title>Environment</title>
774 <variablelist class='environment-variables'>
776 <term><varname>$SYSTEMD_PAGER</varname></term>
777 <listitem><para>Pager to use when
778 <option>--no-pager</option> is not given;
779 overrides <varname>$PAGER</varname>. Setting
780 this to an empty string or the value
781 <literal>cat</literal> is equivalent to passing
782 <option>--no-pager</option>.</para></listitem>
788 <title>Examples</title>
790 <para>Without arguments, all collected logs are shown
793 <programlisting>journalctl</programlisting>
795 <para>With one match specified, all entries with a field matching the expression are shown:</para>
797 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
799 <para>If two different fields are matched, only entries matching both expressions at the same time are shown:</para>
801 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
803 <para>If two matches refer to the same field, all entries matching either expression are shown:</para>
805 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
807 <para>If the separator <literal>+</literal> is used,
808 two expressions may be combined in a logical OR. The
809 following will show all messages from the Avahi
810 service process with the PID 28097 plus all messages
811 from the D-Bus service (from any of its
814 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
816 <para>Show all logs generated by the D-Bus executable:</para>
818 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
820 <para>Show all logs of the kernel device node <filename noindex='true'>/dev/sda</filename>:</para>
822 <programlisting>journalctl /dev/sda</programlisting>
824 <para>Show all kernel logs from last boot:</para>
826 <programlisting>journalctl -k -b :</programlisting>
831 <title>See Also</title>
833 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
834 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
835 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
836 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
837 <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>