1 <?xml version='
1.0'
?> <!--*-nxml-*-->
2 <!DOCTYPE refentry PUBLIC
"-//OASIS//DTD DocBook XML V4.5//EN"
3 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4 <!-- SPDX-License-Identifier: LGPL-2.1+ -->
6 <refentry id=
"journalctl"
7 xmlns:
xi=
"http://www.w3.org/2001/XInclude">
10 <title>journalctl
</title>
11 <productname>systemd
</productname>
15 <refentrytitle>journalctl
</refentrytitle>
16 <manvolnum>1</manvolnum>
20 <refname>journalctl
</refname>
21 <refpurpose>Query the systemd journal
</refpurpose>
26 <command>journalctl
</command>
27 <arg choice=
"opt" rep=
"repeat">OPTIONS
</arg>
28 <arg choice=
"opt" rep=
"repeat">MATCHES
</arg>
33 <title>Description
</title>
35 <para><command>journalctl
</command> may be used to query the
37 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
39 <citerefentry><refentrytitle>systemd-journald.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
41 <para>If called without parameters, it will show the full
42 contents of the journal, starting with the oldest entry
45 <para>If one or more match arguments are passed, the output is
46 filtered accordingly. A match is in the format
47 <literal>FIELD=VALUE
</literal>,
48 e.g.
<literal>_SYSTEMD_UNIT=httpd.service
</literal>, referring
49 to the components of a structured journal entry. See
50 <citerefentry><refentrytitle>systemd.journal-fields
</refentrytitle><manvolnum>7</manvolnum></citerefentry>
51 for a list of well-known fields. If multiple matches are
52 specified matching different fields, the log entries are
53 filtered by both, i.e. the resulting output will show only
54 entries matching all the specified matches of this kind. If two
55 matches apply to the same field, then they are automatically
56 matched as alternatives, i.e. the resulting output will show
57 entries matching any of the specified matches for the same
58 field. Finally, the character
<literal>+
</literal> may appear
59 as a separate word between other terms on the command line. This
60 causes all matches before and after to be combined in a
61 disjunction (i.e. logical OR).
</para>
63 <para>It is also possible to filter the entries by specifying an
64 absolute file path as an argument. The file path may be a file or
65 a symbolic link and the file must exist at the time of the query. If a
66 file path refers to an executable binary, an
<literal>_EXE=
</literal>
67 match for the canonicalized binary path is added to the query. If a
68 file path refers to an executable script, a
<literal>_COMM=
</literal>
69 match for the script name is added to the query. If a file path
70 refers to a device node,
<literal>_KERNEL_DEVICE=
</literal> matches for
71 the kernel name of the device and for each of its ancestor devices is
72 added to the query. Symbolic links are dereferenced, kernel names are
73 synthesized, and parent devices are identified from the environment at
74 the time of the query. In general, a device node is the best proxy for
75 an actual device, as log entries do not usually contain fields that
76 identify an actual device. For the resulting log entries to be correct
77 for the actual device, the relevant parts of the environment at the time
78 the entry was logged, in particular the actual device corresponding to
79 the device node, must have been the same as those at the time of the
80 query. Because device nodes generally change their corresponding devices
81 across reboots, specifying a device node path causes the resulting
82 entries to be restricted to those from the current boot.
</para>
84 <para>Additional constraints may be added using options
85 <option>--boot
</option>,
<option>--unit=
</option>, etc., to
86 further limit what entries will be shown (logical AND).
</para>
88 <para>Output is interleaved from all accessible journal files,
89 whether they are rotated or currently being written, and
90 regardless of whether they belong to the system itself or are
91 accessible user journals.
</para>
93 <para>The set of journal files which will be used can be
94 modified using the
<option>--user
</option>,
95 <option>--system
</option>,
<option>--directory
</option>, and
96 <option>--file
</option> options, see below.
</para>
98 <para>All users are granted access to their private per-user
99 journals. However, by default, only root and users who are
100 members of a few special groups are granted access to the system
101 journal and the journals of other users. Members of the groups
102 <literal>systemd-journal
</literal>,
<literal>adm
</literal>, and
103 <literal>wheel
</literal> can read all journal files. Note
104 that the two latter groups traditionally have additional
105 privileges specified by the distribution. Members of the
106 <literal>wheel
</literal> group can often perform administrative
109 <para>The output is paged through
<command>less
</command> by
110 default, and long lines are
"truncated" to screen width. The
111 hidden part can be viewed by using the left-arrow and
112 right-arrow keys. Paging can be disabled; see the
113 <option>--no-pager
</option> option and the
"Environment" section
116 <para>When outputting to a tty, lines are colored according to
117 priority: lines of level ERROR and higher are colored red; lines
118 of level NOTICE and higher are highlighted; lines of level DEBUG
119 are colored lighter grey; other lines are displayed normally.
</para>
123 <title>Options
</title>
125 <para>The following options are understood:
</para>
129 <term><option>--no-full
</option></term>
130 <term><option>--full
</option></term>
131 <term><option>-l
</option></term>
133 <listitem><para>Ellipsize fields when they do not fit in
134 available columns. The default is to show full fields,
135 allowing them to wrap or be truncated by the pager, if one
138 <para>The old options
139 <option>-l
</option>/
<option>--full
</option> are not useful
140 anymore, except to undo
<option>--no-full
</option>.
</para>
145 <term><option>-a
</option></term>
146 <term><option>--all
</option></term>
148 <listitem><para>Show all fields in full, even if they include unprintable characters or are very long. By
149 default, fields with unprintable characters are abbreviated as
"blob data". (Note that the pager may escape
150 unprintable characters again.)
</para></listitem>
154 <term><option>-f
</option></term>
155 <term><option>--follow
</option></term>
157 <listitem><para>Show only the most recent journal entries,
158 and continuously print new entries as they are appended to
159 the journal.
</para></listitem>
163 <term><option>-e
</option></term>
164 <term><option>--pager-end
</option></term>
166 <listitem><para>Immediately jump to the end of the journal
167 inside the implied pager tool. This implies
168 <option>-n1000
</option> to guarantee that the pager will not
169 buffer logs of unbounded size. This may be overridden with
170 an explicit
<option>-n
</option> with some other numeric
171 value, while
<option>-nall
</option> will disable this cap.
172 Note that this option is only supported for the
173 <citerefentry project='man-pages'
><refentrytitle>less
</refentrytitle><manvolnum>1</manvolnum></citerefentry>
174 pager.
</para></listitem>
178 <term><option>-n
</option></term>
179 <term><option>--lines=
</option></term>
181 <listitem><para>Show the most recent journal events and
182 limit the number of events shown. If
183 <option>--follow
</option> is used, this option is
184 implied. The argument is a positive integer or
185 <literal>all
</literal> to disable line limiting. The default
186 value is
10 if no argument is given.
</para></listitem>
190 <term><option>--no-tail
</option></term>
192 <listitem><para>Show all stored output lines, even in follow
193 mode. Undoes the effect of
<option>--lines=
</option>.
198 <term><option>-r
</option></term>
199 <term><option>--reverse
</option></term>
201 <listitem><para>Reverse output so that the newest entries
202 are displayed first.
</para></listitem>
206 <term><option>-o
</option></term>
207 <term><option>--output=
</option></term>
209 <listitem><para>Controls the formatting of the journal
210 entries that are shown. Takes one of the following
215 <option>short
</option>
218 <para>is the default and generates an output that is
219 mostly identical to the formatting of classic syslog
220 files, showing one line per journal entry.
</para>
226 <option>short-full
</option>
229 <para>is very similar, but shows timestamps in the format the
<option>--since=
</option> and
230 <option>--until=
</option> options accept. Unlike the timestamp information shown in
231 <option>short
</option> output mode this mode includes weekday, year and timezone information in the
232 output, and is locale-independent.
</para>
238 <option>short-iso
</option>
241 <para>is very similar, but shows ISO
8601 wallclock
248 <option>short-iso-precise
</option>
251 <para>as for
<option>short-iso
</option> but includes full
252 microsecond precision.
</para>
258 <option>short-precise
</option>
261 <para>is very similar, but shows classic syslog timestamps
262 with full microsecond precision.
</para>
268 <option>short-monotonic
</option>
271 <para>is very similar, but shows monotonic timestamps
272 instead of wallclock timestamps.
</para>
278 <option>short-unix
</option>
281 <para>is very similar, but shows seconds passed since January
1st
1970 UTC instead of wallclock
282 timestamps (
"UNIX time"). The time is shown with microsecond accuracy.
</para>
288 <option>verbose
</option>
291 <para>shows the full-structured entry items with all
298 <option>export
</option>
301 <para>serializes the journal into a binary (but mostly
302 text-based) stream suitable for backups and network
304 <ulink url=
"https://www.freedesktop.org/wiki/Software/systemd/export">Journal Export Format
</ulink>
305 for more information). To import the binary stream back
306 into native journald format use
307 <citerefentry><refentrytitle>systemd-journal-remote
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para>
313 <option>json
</option>
316 <para>formats entries as JSON objects, separated by newline characters (see
<ulink
317 url=
"https://www.freedesktop.org/wiki/Software/systemd/json">Journal JSON Format
</ulink> for more
318 information). Field values are generally encoded as JSON strings, with three exceptions:
320 <listitem><para>Fields larger than
4096 bytes are encoded as
<constant>null
</constant> values. (This
321 may be turned off by passing
<option>--all
</option>, but be aware that this may allocate overly long
322 JSON objects.)
</para></listitem>
324 <listitem><para>Journal entries permit non-unique fields within the same log entry. JSON does not allow
325 non-unique fields within objects. Due to this, if a non-unique field is encountered a JSON array is
326 used as field value, listing all field values as elements.
</para></listitem>
328 <listitem><para>Fields containing non-printable or non-UTF8 bytes are encoded as arrays containing
329 the raw bytes individually formatted as unsigned numbers.
</para></listitem>
332 Note that this encoding is reversible (with the exception of the size limit).
</para>
338 <option>json-pretty
</option>
341 <para>formats entries as JSON data structures, but
342 formats them in multiple lines in order to make them
343 more readable by humans.
</para>
349 <option>json-sse
</option>
352 <para>formats entries as JSON data structures, but wraps
353 them in a format suitable for
354 <ulink url=
"https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent Events
</ulink>.
361 <option>json-seq
</option>
364 <para>formats entries as JSON data structures, but prefixes them with an ASCII Record Separator
365 character (
0x1E) and suffixes them with an ASCII Line Feed character (
0x0A), in accordance with
<ulink
366 url=
"https://tools.ietf.org/html/rfc7464">JavaScript Object Notation (JSON) Text Sequences
</ulink>
367 (
<literal>application/json-seq
</literal>).
377 <para>generates a very terse output, only showing the
378 actual message of each journal entry with no metadata,
379 not even a timestamp.
</para>
385 <option>with-unit
</option>
388 <para>similar to short-full, but prefixes the unit and
389 user unit names instead of the traditional syslog
390 identifier. Useful when using templated instances, as it
391 will include the arguments in the unit names.
</para>
399 <term><option>--output-fields=
</option></term>
401 <listitem><para>A comma separated list of the fields which should be included in the output. This only has an
402 effect for the output modes which would normally show all fields (
<option>verbose
</option>,
403 <option>export
</option>,
<option>json
</option>,
<option>json-pretty
</option>,
<option>json-sse
</option> and
404 <option>json-seq
</option>). The
<literal>__CURSOR
</literal>,
<literal>__REALTIME_TIMESTAMP
</literal>,
405 <literal>__MONOTONIC_TIMESTAMP
</literal>, and
<literal>_BOOT_ID
</literal> fields are always
406 printed.
</para></listitem>
410 <term><option>--utc
</option></term>
412 <listitem><para>Express time in Coordinated Universal Time
413 (UTC).
</para></listitem>
417 <term><option>--no-hostname
</option></term>
419 <listitem><para>Don't show the hostname field of log messages originating from the local host. This switch only
420 has an effect on the
<option>short
</option> family of output modes (see above).
</para></listitem>
424 <term><option>-x
</option></term>
425 <term><option>--catalog
</option></term>
427 <listitem><para>Augment log lines with explanation texts from
428 the message catalog. This will add explanatory help texts to
429 log messages in the output where this is available. These
430 short help texts will explain the context of an error or log
431 event, possible solutions, as well as pointers to support
432 forums, developer documentation, and any other relevant
433 manuals. Note that help texts are not available for all
434 messages, but only for selected ones. For more information on
435 the message catalog, please refer to the
436 <ulink url=
"https://www.freedesktop.org/wiki/Software/systemd/catalog">Message Catalog Developer Documentation
</ulink>.
</para>
438 <para>Note: when attaching
<command>journalctl
</command>
439 output to bug reports, please do
<emphasis>not
</emphasis> use
440 <option>-x
</option>.
</para>
445 <term><option>-q
</option></term>
446 <term><option>--quiet
</option></term>
448 <listitem><para>Suppresses all informational messages
449 (i.e.
"-- Logs begin at …",
"-- Reboot --"),
450 any warning messages regarding
451 inaccessible system journals when run as a normal
452 user.
</para></listitem>
456 <term><option>-m
</option></term>
457 <term><option>--merge
</option></term>
459 <listitem><para>Show entries interleaved from all available
460 journals, including remote ones.
</para></listitem>
464 <term><option>-b
<optional><replaceable>ID
</replaceable></optional><optional><replaceable>±offset
</replaceable></optional></option></term>
465 <term><option>--boot=
<optional><replaceable>ID
</replaceable></optional><optional><replaceable>±offset
</replaceable></optional></option></term>
467 <listitem><para>Show messages from a specific boot. This will
468 add a match for
<literal>_BOOT_ID=
</literal>.
</para>
470 <para>The argument may be empty, in which case logs for the
471 current boot will be shown.
</para>
473 <para>If the boot ID is omitted, a positive
474 <replaceable>offset
</replaceable> will look up the boots
475 starting from the beginning of the journal, and an
476 equal-or-less-than zero
<replaceable>offset
</replaceable> will
477 look up boots starting from the end of the journal. Thus,
478 <constant>1</constant> means the first boot found in the
479 journal in chronological order,
<constant>2</constant> the
480 second and so on; while
<constant>-
0</constant> is the last
481 boot,
<constant>-
1</constant> the boot before last, and so
482 on. An empty
<replaceable>offset
</replaceable> is equivalent
483 to specifying
<constant>-
0</constant>, except when the current
484 boot is not the last boot (e.g. because
485 <option>--directory
</option> was specified to look at logs
486 from a different machine).
</para>
488 <para>If the
32-character
<replaceable>ID
</replaceable> is
489 specified, it may optionally be followed by
490 <replaceable>offset
</replaceable> which identifies the boot
491 relative to the one given by boot
492 <replaceable>ID
</replaceable>. Negative values mean earlier
493 boots and positive values mean later boots. If
494 <replaceable>offset
</replaceable> is not specified, a value of
495 zero is assumed, and the logs for the boot given by
496 <replaceable>ID
</replaceable> are shown.
</para>
501 <term><option>--list-boots
</option></term>
503 <listitem><para>Show a tabular list of boot numbers (relative to
504 the current boot), their IDs, and the timestamps of the first
505 and last message pertaining to the boot.
</para></listitem>
509 <term><option>-k
</option></term>
510 <term><option>--dmesg
</option></term>
512 <listitem><para>Show only kernel messages. This implies
513 <option>-b
</option> and adds the match
514 <literal>_TRANSPORT=kernel
</literal>.
</para></listitem>
518 <term><option>-t
</option></term>
519 <term><option>--identifier=
<replaceable>SYSLOG_IDENTIFIER
</replaceable></option></term>
521 <listitem><para>Show messages for the specified syslog
523 <replaceable>SYSLOG_IDENTIFIER
</replaceable>.
</para>
525 <para>This parameter can be specified multiple
526 times.
</para></listitem>
530 <term><option>-u
</option></term>
531 <term><option>--unit=
<replaceable>UNIT
</replaceable>|
<replaceable>PATTERN
</replaceable></option></term>
533 <listitem><para>Show messages for the specified systemd unit
534 <replaceable>UNIT
</replaceable> (such as a service unit), or
535 for any of the units matched by
536 <replaceable>PATTERN
</replaceable>. If a pattern is
537 specified, a list of unit names found in the journal is
538 compared with the specified pattern and all that match are
539 used. For each unit name, a match is added for messages from
541 (
<literal>_SYSTEMD_UNIT=
<replaceable>UNIT
</replaceable></literal>),
542 along with additional matches for messages from systemd and
543 messages about coredumps for the specified unit.
</para>
545 <para>This parameter can be specified multiple times.
</para>
550 <term><option>--user-unit=
</option></term>
552 <listitem><para>Show messages for the specified user session
553 unit. This will add a match for messages from the unit
554 (
<literal>_SYSTEMD_USER_UNIT=
</literal> and
555 <literal>_UID=
</literal>) and additional matches for messages
556 from session systemd and messages about coredumps for the
557 specified unit.
</para>
559 <para>This parameter can be specified multiple times.
</para>
564 <term><option>-p
</option></term>
565 <term><option>--priority=
</option></term>
567 <listitem><para>Filter output by message priorities or
568 priority ranges. Takes either a single numeric or textual log
569 level (i.e. between
0/
<literal>emerg
</literal> and
570 7/
<literal>debug
</literal>), or a range of numeric/text log
571 levels in the form FROM..TO. The log levels are the usual
572 syslog log levels as documented in
573 <citerefentry project='man-pages'
><refentrytitle>syslog
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
574 i.e.
<literal>emerg
</literal> (
0),
575 <literal>alert
</literal> (
1),
<literal>crit
</literal> (
2),
576 <literal>err
</literal> (
3),
<literal>warning
</literal> (
4),
577 <literal>notice
</literal> (
5),
<literal>info
</literal> (
6),
578 <literal>debug
</literal> (
7). If a single log level is
579 specified, all messages with this log level or a lower (hence
580 more important) log level are shown. If a range is specified,
581 all messages within the range are shown, including both the
582 start and the end value of the range. This will add
583 <literal>PRIORITY=
</literal> matches for the specified
584 priorities.
</para></listitem>
588 <term><option>-g
</option></term>
589 <term><option>--grep=
</option></term>
591 <listitem><para>Filter output to entries where the
<varname>MESSAGE=
</varname>
592 field matches the specified regular expression. PERL-compatible regular expressions
594 <citerefentry><refentrytitle>pcre2pattern
</refentrytitle><manvolnum>3</manvolnum></citerefentry>
595 for a detailed description of the syntax.
</para>
597 <para>If the pattern is all lowercase, matching is case insensitive.
598 Otherwise, matching is case sensitive. This can be overridden with the
599 <option>--case-sensitive
</option> option, see below.
</para>
604 <term><option>--case-sensitive
<optional>=BOOLEAN
</optional></option></term>
606 <listitem><para>Make pattern matching case sensitive or case insenstive.
</para>
611 <term><option>-c
</option></term>
612 <term><option>--cursor=
</option></term>
614 <listitem><para>Start showing entries from the location in the
615 journal specified by the passed cursor.
</para></listitem>
619 <term><option>--cursor-file=
<replaceable>FILE
</replaceable></option></term>
621 <listitem><para>If
<replaceable>FILE
</replaceable> exists and contains a
622 cursor, start showing entries
<emphasis>after
</emphasis> this location.
623 Otherwise the show entries according the other given options. At the end,
624 write the cursor of the last entry to
<replaceable>FILE
</replaceable>. Use
625 this option to continually read the journal by sequentially calling
626 <command>journalctl
</command>.
</para></listitem>
630 <term><option>--after-cursor=
</option></term>
632 <listitem><para>Start showing entries from the location in the
633 journal
<emphasis>after
</emphasis> the location specified by
634 the passed cursor. The cursor is shown when the
635 <option>--show-cursor
</option> option is used.
</para>
640 <term><option>--show-cursor
</option></term>
642 <listitem><para>The cursor is shown after the last entry after
644 <programlisting>-- cursor: s=
0639…
</programlisting>
645 <para>The format of the cursor is private
646 and subject to change.
</para></listitem>
650 <term><option>-S
</option></term>
651 <term><option>--since=
</option></term>
652 <term><option>-U
</option></term>
653 <term><option>--until=
</option></term>
655 <listitem><para>Start showing entries on or newer than the specified date, or on or older than the specified
656 date, respectively. Date specifications should be of the format
<literal>2012-
10-
30 18:
17:
16</literal>. If the
657 time part is omitted,
<literal>00:
00:
00</literal> is assumed. If only the seconds component is omitted,
658 <literal>:
00</literal> is assumed. If the date component is omitted, the current day is assumed. Alternatively
659 the strings
<literal>yesterday
</literal>,
<literal>today
</literal>,
<literal>tomorrow
</literal> are understood,
660 which refer to
00:
00:
00 of the day before the current day, the current day, or the day after the current day,
661 respectively.
<literal>now
</literal> refers to the current time. Finally, relative times may be specified,
662 prefixed with
<literal>-
</literal> or
<literal>+
</literal>, referring to times before or after the current
663 time, respectively. For complete time and date specification, see
664 <citerefentry><refentrytitle>systemd.time
</refentrytitle><manvolnum>7</manvolnum></citerefentry>. Note that
665 <option>--output=short-full
</option> prints timestamps that follow precisely this format.
671 <term><option>-F
</option></term>
672 <term><option>--field=
</option></term>
674 <listitem><para>Print all possible data values the specified
675 field can take in all entries of the journal.
</para></listitem>
679 <term><option>-N
</option></term>
680 <term><option>--fields
</option></term>
682 <listitem><para>Print all field names currently used in all entries of the journal.
</para></listitem>
686 <term><option>--system
</option></term>
687 <term><option>--user
</option></term>
689 <listitem><para>Show messages from system services and the
690 kernel (with
<option>--system
</option>). Show messages from
691 service of current user (with
<option>--user
</option>). If
692 neither is specified, show all messages that the user can see.
697 <term><option>-M
</option></term>
698 <term><option>--machine=
</option></term>
700 <listitem><para>Show messages from a running, local
701 container. Specify a container name to connect to.
</para>
706 <term><option>-D
<replaceable>DIR
</replaceable></option></term>
707 <term><option>--directory=
<replaceable>DIR
</replaceable></option></term>
709 <listitem><para>Takes a directory path as argument. If
710 specified, journalctl will operate on the specified journal
711 directory
<replaceable>DIR
</replaceable> instead of the
712 default runtime and system journal paths.
</para></listitem>
716 <term><option>--file=
<replaceable>GLOB
</replaceable></option></term>
718 <listitem><para>Takes a file glob as an argument. If
719 specified, journalctl will operate on the specified journal
720 files matching
<replaceable>GLOB
</replaceable> instead of the
721 default runtime and system journal paths. May be specified
722 multiple times, in which case files will be suitably
723 interleaved.
</para></listitem>
727 <term><option>--root=
<replaceable>ROOT
</replaceable></option></term>
729 <listitem><para>Takes a directory path as an argument. If
730 specified, journalctl will operate on journal directories and catalog file hierarchy
731 underneath the specified directory instead of the root
732 directory (e.g.
<option>--update-catalog
</option> will create
733 <filename><replaceable>ROOT
</replaceable>/var/lib/systemd/catalog/database
</filename>,
734 and journal files under
<filename><replaceable>ROOT
</replaceable>/run/journal
</filename>
735 or
<filename><replaceable>ROOT
</replaceable>/var/log/journal
</filename> will be displayed).
740 <term><option>--header
</option></term>
742 <listitem><para>Instead of showing journal contents, show
743 internal header information of the journal fields
744 accessed.
</para></listitem>
748 <term><option>--disk-usage
</option></term>
750 <listitem><para>Shows the current disk usage of all journal
751 files. This shows the sum of the disk usage of all archived
752 and active journal files.
</para></listitem>
756 <term><option>--vacuum-size=
</option></term>
757 <term><option>--vacuum-time=
</option></term>
758 <term><option>--vacuum-files=
</option></term>
760 <listitem><para>Removes the oldest archived journal files until the disk space they use falls below the
761 specified size (specified with the usual
<literal>K
</literal>,
<literal>M
</literal>,
<literal>G
</literal> and
762 <literal>T
</literal> suffixes), or all archived journal files contain no data older than the specified timespan
763 (specified with the usual
<literal>s
</literal>,
<literal>m
</literal>,
<literal>h
</literal>,
764 <literal>days
</literal>,
<literal>months
</literal>,
<literal>weeks
</literal> and
<literal>years
</literal>
765 suffixes), or no more than the specified number of separate journal files remain. Note that running
766 <option>--vacuum-size=
</option> has only an indirect effect on the output shown by
767 <option>--disk-usage
</option>, as the latter includes active journal files, while the vacuuming operation only
768 operates on archived journal files. Similarly,
<option>--vacuum-files=
</option> might not actually reduce the
769 number of journal files to below the specified number, as it will not remove active journal
772 <para><option>--vacuum-size=
</option>,
<option>--vacuum-time=
</option> and
<option>--vacuum-files=
</option>
773 may be combined in a single invocation to enforce any combination of a size, a time and a number of files limit
774 on the archived journal files. Specifying any of these three parameters as zero is equivalent to not enforcing
775 the specific limit, and is thus redundant.
</para>
777 <para>These three switches may also be combined with
<option>--rotate
</option> into one command. If so, all
778 active files are rotated first, and the requested vacuuming operation is executed right after. The rotation has
779 the effect that all currently active files are archived (and potentially new, empty journal files opened as
780 replacement), and hence the vacuuming operation has the greatest effect as it can take all log data written so
781 far into account.
</para></listitem>
785 <term><option>--list-catalog
786 <optional><replaceable>128-bit-ID…
</replaceable></optional>
789 <listitem><para>List the contents of the message catalog as a
790 table of message IDs, plus their short description strings.
793 <para>If any
<replaceable>128-bit-ID
</replaceable>s are
794 specified, only those entries are shown.
</para>
799 <term><option>--dump-catalog
800 <optional><replaceable>128-bit-ID…
</replaceable></optional>
803 <listitem><para>Show the contents of the message catalog, with
804 entries separated by a line consisting of two dashes and the
805 ID (the format is the same as
<filename>.catalog
</filename>
808 <para>If any
<replaceable>128-bit-ID
</replaceable>s are
809 specified, only those entries are shown.
</para>
814 <term><option>--update-catalog
</option></term>
816 <listitem><para>Update the message catalog index. This command
817 needs to be executed each time new catalog files are
818 installed, removed, or updated to rebuild the binary catalog
819 index.
</para></listitem>
823 <term><option>--setup-keys
</option></term>
825 <listitem><para>Instead of showing journal contents, generate
826 a new key pair for Forward Secure Sealing (FSS). This will
827 generate a sealing key and a verification key. The sealing key
828 is stored in the journal data directory and shall remain on
829 the host. The verification key should be stored
830 externally. Refer to the
<option>Seal=
</option> option in
831 <citerefentry><refentrytitle>journald.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
832 for information on Forward Secure Sealing and for a link to a
833 refereed scholarly paper detailing the cryptographic theory it
834 is based on.
</para></listitem>
838 <term><option>--force
</option></term>
840 <listitem><para>When
<option>--setup-keys
</option> is passed
841 and Forward Secure Sealing (FSS) has already been configured,
842 recreate FSS keys.
</para></listitem>
846 <term><option>--interval=
</option></term>
848 <listitem><para>Specifies the change interval for the sealing
849 key when generating an FSS key pair with
850 <option>--setup-keys
</option>. Shorter intervals increase CPU
851 consumption but shorten the time range of undetectable journal
852 alterations. Defaults to
15min.
</para></listitem>
856 <term><option>--verify
</option></term>
858 <listitem><para>Check the journal file for internal
859 consistency. If the file has been generated with FSS enabled and
860 the FSS verification key has been specified with
861 <option>--verify-key=
</option>, authenticity of the journal file
862 is verified.
</para></listitem>
866 <term><option>--verify-key=
</option></term>
868 <listitem><para>Specifies the FSS verification key to use for
869 the
<option>--verify
</option> operation.
</para></listitem>
873 <term><option>--sync
</option></term>
875 <listitem><para>Asks the journal daemon to write all yet
876 unwritten journal data to the backing file system and
877 synchronize all journals. This call does not return until the
878 synchronization operation is complete. This command guarantees
879 that any log messages written before its invocation are safely
880 stored on disk at the time it returns.
</para></listitem>
884 <term><option>--flush
</option></term>
886 <listitem><para>Asks the journal daemon to flush any log data
887 stored in
<filename>/run/log/journal
</filename> into
888 <filename>/var/log/journal
</filename>, if persistent storage
889 is enabled. This call does not return until the operation is
890 complete. Note that this call is idempotent: the data is only
891 flushed from
<filename>/run/log/journal
</filename> into
892 <filename>/var/log/journal
</filename> once during system
893 runtime, and this command exits cleanly without executing any
894 operation if this has already happened. This command
895 effectively guarantees that all data is flushed to
896 <filename>/var/log/journal
</filename> at the time it
897 returns.
</para></listitem>
901 <term><option>--rotate
</option></term>
903 <listitem><para>Asks the journal daemon to rotate journal files. This call does not return until the rotation
904 operation is complete. Journal file rotation has the effect that all currently active journal files are marked
905 as archived and renamed, so that they are never written to in future. New (empty) journal files are then
906 created in their place. This operation may be combined with
<option>--vacuum-size=
</option>,
907 <option>--vacuum-time=
</option> and
<option>--vacuum-file=
</option> into a single command, see
908 above.
</para></listitem>
911 <xi:include href=
"standard-options.xml" xpointer=
"help" />
912 <xi:include href=
"standard-options.xml" xpointer=
"version" />
913 <xi:include href=
"standard-options.xml" xpointer=
"no-pager" />
918 <title>Exit status
</title>
920 <para>On success,
0 is returned; otherwise, a non-zero failure
921 code is returned.
</para>
924 <xi:include href=
"less-variables.xml" />
927 <title>Examples
</title>
929 <para>Without arguments, all collected logs are shown
932 <programlisting>journalctl
</programlisting>
934 <para>With one match specified, all entries with a field matching
935 the expression are shown:
</para>
937 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service
938 journalctl _SYSTEMD_CGROUP=/user.slice/user-
42.slice/session-c1.scope
</programlisting>
940 <para>If two different fields are matched, only entries matching
941 both expressions at the same time are shown:
</para>
943 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=
28097</programlisting>
945 <para>If two matches refer to the same field, all entries matching
946 either expression are shown:
</para>
948 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service
</programlisting>
950 <para>If the separator
<literal>+
</literal> is used, two
951 expressions may be combined in a logical OR. The following will
952 show all messages from the Avahi service process with the PID
953 28097 plus all messages from the D-Bus service (from any of its
956 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=
28097 + _SYSTEMD_UNIT=dbus.service
</programlisting>
958 <para>To show all fields emitted
<emphasis>by
</emphasis> a unit and
<emphasis>about
</emphasis>
959 the unit, option
<option>-u
</option>/
<option>--unit=
</option> should be used.
960 <command>journalctl -u
<replaceable>name
</replaceable></command>
961 expands to a complex filter similar to
962 <programlisting>_SYSTEMD_UNIT=
<replaceable>name
</replaceable>.service
963 + UNIT=
<replaceable>name
</replaceable>.service _PID=
1
964 + OBJECT_SYSTEMD_UNIT=
<replaceable>name
</replaceable>.service _UID=
0
965 + COREDUMP_UNIT=
<replaceable>name
</replaceable>.service _UID=
0 MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1
967 (see
<citerefentry><refentrytitle>systemd.journal-fields
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
968 for an explanation of those patterns).
971 <para>Show all logs generated by the D-Bus executable:
</para>
973 <programlisting>journalctl /usr/bin/dbus-daemon
</programlisting>
975 <para>Show all kernel logs from previous boot:
</para>
977 <programlisting>journalctl -k -b -
1</programlisting>
979 <para>Show a live log display from a system service
980 <filename>apache.service
</filename>:
</para>
982 <programlisting>journalctl -f -u apache
</programlisting>
987 <title>See Also
</title>
989 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
990 <citerefentry><refentrytitle>systemd-journald.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
991 <citerefentry><refentrytitle>systemctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
992 <citerefentry><refentrytitle>coredumpctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
993 <citerefentry><refentrytitle>systemd.journal-fields
</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
994 <citerefentry><refentrytitle>journald.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
995 <citerefentry><refentrytitle>systemd.time
</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
996 <citerefentry><refentrytitle>systemd-journal-remote.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
997 <citerefentry><refentrytitle>systemd-journal-upload.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>