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 has an
402 effect only 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
420 switch has an effect only on the
<option>short
</option> family of output modes (see above).
423 <para>Note: this option does not remove occurrences of the hostname from log entries themselves, so
424 it does not prevent the hostname from being visible in the logs.
</para>
429 <term><option>-x
</option></term>
430 <term><option>--catalog
</option></term>
432 <listitem><para>Augment log lines with explanation texts from
433 the message catalog. This will add explanatory help texts to
434 log messages in the output where this is available. These
435 short help texts will explain the context of an error or log
436 event, possible solutions, as well as pointers to support
437 forums, developer documentation, and any other relevant
438 manuals. Note that help texts are not available for all
439 messages, but only for selected ones. For more information on
440 the message catalog, please refer to the
441 <ulink url=
"https://www.freedesktop.org/wiki/Software/systemd/catalog">Message Catalog Developer Documentation
</ulink>.
</para>
443 <para>Note: when attaching
<command>journalctl
</command>
444 output to bug reports, please do
<emphasis>not
</emphasis> use
445 <option>-x
</option>.
</para>
450 <term><option>-q
</option></term>
451 <term><option>--quiet
</option></term>
453 <listitem><para>Suppresses all informational messages
454 (i.e.
"-- Logs begin at …",
"-- Reboot --"),
455 any warning messages regarding
456 inaccessible system journals when run as a normal
457 user.
</para></listitem>
461 <term><option>-m
</option></term>
462 <term><option>--merge
</option></term>
464 <listitem><para>Show entries interleaved from all available
465 journals, including remote ones.
</para></listitem>
469 <term><option>-b
<optional><optional><replaceable>ID
</replaceable></optional><optional><replaceable>±offset
</replaceable></optional>|
<constant>all
</constant></optional></option></term>
470 <term><option>--boot
<optional>=
<optional><replaceable>ID
</replaceable></optional><optional><replaceable>±offset
</replaceable></optional>|
<constant>all
</constant></optional></option></term>
472 <listitem><para>Show messages from a specific boot. This will
473 add a match for
<literal>_BOOT_ID=
</literal>.
</para>
475 <para>The argument may be empty, in which case logs for the
476 current boot will be shown.
</para>
478 <para>If the boot ID is omitted, a positive
479 <replaceable>offset
</replaceable> will look up the boots
480 starting from the beginning of the journal, and an
481 equal-or-less-than zero
<replaceable>offset
</replaceable> will
482 look up boots starting from the end of the journal. Thus,
483 <constant>1</constant> means the first boot found in the
484 journal in chronological order,
<constant>2</constant> the
485 second and so on; while
<constant>-
0</constant> is the last
486 boot,
<constant>-
1</constant> the boot before last, and so
487 on. An empty
<replaceable>offset
</replaceable> is equivalent
488 to specifying
<constant>-
0</constant>, except when the current
489 boot is not the last boot (e.g. because
490 <option>--directory
</option> was specified to look at logs
491 from a different machine).
</para>
493 <para>If the
32-character
<replaceable>ID
</replaceable> is
494 specified, it may optionally be followed by
495 <replaceable>offset
</replaceable> which identifies the boot
496 relative to the one given by boot
497 <replaceable>ID
</replaceable>. Negative values mean earlier
498 boots and positive values mean later boots. If
499 <replaceable>offset
</replaceable> is not specified, a value of
500 zero is assumed, and the logs for the boot given by
501 <replaceable>ID
</replaceable> are shown.
</para>
503 <para>The special argument
<constant>all
</constant> can be
504 used to negate the effect of an earlier use of
505 <option>-b
</option>.
</para>
510 <term><option>--list-boots
</option></term>
512 <listitem><para>Show a tabular list of boot numbers (relative to
513 the current boot), their IDs, and the timestamps of the first
514 and last message pertaining to the boot.
</para></listitem>
518 <term><option>-k
</option></term>
519 <term><option>--dmesg
</option></term>
521 <listitem><para>Show only kernel messages. This implies
522 <option>-b
</option> and adds the match
523 <literal>_TRANSPORT=kernel
</literal>.
</para></listitem>
527 <term><option>-t
</option></term>
528 <term><option>--identifier=
<replaceable>SYSLOG_IDENTIFIER
</replaceable></option></term>
530 <listitem><para>Show messages for the specified syslog
532 <replaceable>SYSLOG_IDENTIFIER
</replaceable>.
</para>
534 <para>This parameter can be specified multiple
535 times.
</para></listitem>
539 <term><option>-u
</option></term>
540 <term><option>--unit=
<replaceable>UNIT
</replaceable>|
<replaceable>PATTERN
</replaceable></option></term>
542 <listitem><para>Show messages for the specified systemd unit
543 <replaceable>UNIT
</replaceable> (such as a service unit), or
544 for any of the units matched by
545 <replaceable>PATTERN
</replaceable>. If a pattern is
546 specified, a list of unit names found in the journal is
547 compared with the specified pattern and all that match are
548 used. For each unit name, a match is added for messages from
550 (
<literal>_SYSTEMD_UNIT=
<replaceable>UNIT
</replaceable></literal>),
551 along with additional matches for messages from systemd and
552 messages about coredumps for the specified unit. A match
553 is also added for
<literal>_SYSTEMD_SLICE=
<replaceable>UNIT
</replaceable></literal>,
554 such that if the provided
<replaceable>UNIT
</replaceable> is a
555 <citerefentry><refentrytitle>systemd.slice
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
556 unit, all logs of the children of the slice will be logged.
559 <para>This parameter can be specified multiple times.
</para>
564 <term><option>--user-unit=
</option></term>
566 <listitem><para>Show messages for the specified user session
567 unit. This will add a match for messages from the unit
568 (
<literal>_SYSTEMD_USER_UNIT=
</literal> and
569 <literal>_UID=
</literal>) and additional matches for messages
570 from session systemd and messages about coredumps for the
571 specified unit. A match
572 is also added for
<literal>_SYSTEMD_USER_SLICE=
<replaceable>UNIT
</replaceable></literal>,
573 such that if the provided
<replaceable>UNIT
</replaceable> is a
574 <citerefentry><refentrytitle>systemd.slice
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
575 unit, all logs of the children of the unit will be logged.
</para>
577 <para>This parameter can be specified multiple times.
</para>
582 <term><option>-p
</option></term>
583 <term><option>--priority=
</option></term>
585 <listitem><para>Filter output by message priorities or
586 priority ranges. Takes either a single numeric or textual log
587 level (i.e. between
0/
<literal>emerg
</literal> and
588 7/
<literal>debug
</literal>), or a range of numeric/text log
589 levels in the form FROM..TO. The log levels are the usual
590 syslog log levels as documented in
591 <citerefentry project='man-pages'
><refentrytitle>syslog
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
592 i.e.
<literal>emerg
</literal> (
0),
593 <literal>alert
</literal> (
1),
<literal>crit
</literal> (
2),
594 <literal>err
</literal> (
3),
<literal>warning
</literal> (
4),
595 <literal>notice
</literal> (
5),
<literal>info
</literal> (
6),
596 <literal>debug
</literal> (
7). If a single log level is
597 specified, all messages with this log level or a lower (hence
598 more important) log level are shown. If a range is specified,
599 all messages within the range are shown, including both the
600 start and the end value of the range. This will add
601 <literal>PRIORITY=
</literal> matches for the specified
602 priorities.
</para></listitem>
606 <term><option>--facility=
</option></term>
608 <listitem><para>Filter output by syslog facility. Takes a comma-separated list of numbers or facility
609 names. The names are the usual syslog facilities as documented in
610 <citerefentry project='man-pages'
><refentrytitle>syslog
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
611 <option>--facility=help
</option> may be used to display a list of known facility names and exit.
616 <term><option>-g
</option></term>
617 <term><option>--grep=
</option></term>
619 <listitem><para>Filter output to entries where the
<varname>MESSAGE=
</varname>
620 field matches the specified regular expression. PERL-compatible regular expressions
622 <citerefentry><refentrytitle>pcre2pattern
</refentrytitle><manvolnum>3</manvolnum></citerefentry>
623 for a detailed description of the syntax.
</para>
625 <para>If the pattern is all lowercase, matching is case insensitive.
626 Otherwise, matching is case sensitive. This can be overridden with the
627 <option>--case-sensitive
</option> option, see below.
</para>
632 <term><option>--case-sensitive
<optional>=BOOLEAN
</optional></option></term>
634 <listitem><para>Make pattern matching case sensitive or case insenstive.
</para>
639 <term><option>-c
</option></term>
640 <term><option>--cursor=
</option></term>
642 <listitem><para>Start showing entries from the location in the
643 journal specified by the passed cursor.
</para></listitem>
647 <term><option>--cursor-file=
<replaceable>FILE
</replaceable></option></term>
649 <listitem><para>If
<replaceable>FILE
</replaceable> exists and contains a
650 cursor, start showing entries
<emphasis>after
</emphasis> this location.
651 Otherwise the show entries according the other given options. At the end,
652 write the cursor of the last entry to
<replaceable>FILE
</replaceable>. Use
653 this option to continually read the journal by sequentially calling
654 <command>journalctl
</command>.
</para></listitem>
658 <term><option>--after-cursor=
</option></term>
660 <listitem><para>Start showing entries from the location in the
661 journal
<emphasis>after
</emphasis> the location specified by
662 the passed cursor. The cursor is shown when the
663 <option>--show-cursor
</option> option is used.
</para>
668 <term><option>--show-cursor
</option></term>
670 <listitem><para>The cursor is shown after the last entry after
672 <programlisting>-- cursor: s=
0639…
</programlisting>
673 <para>The format of the cursor is private
674 and subject to change.
</para></listitem>
678 <term><option>-S
</option></term>
679 <term><option>--since=
</option></term>
680 <term><option>-U
</option></term>
681 <term><option>--until=
</option></term>
683 <listitem><para>Start showing entries on or newer than the specified date, or on or older than the specified
684 date, respectively. Date specifications should be of the format
<literal>2012-
10-
30 18:
17:
16</literal>. If the
685 time part is omitted,
<literal>00:
00:
00</literal> is assumed. If only the seconds component is omitted,
686 <literal>:
00</literal> is assumed. If the date component is omitted, the current day is assumed. Alternatively
687 the strings
<literal>yesterday
</literal>,
<literal>today
</literal>,
<literal>tomorrow
</literal> are understood,
688 which refer to
00:
00:
00 of the day before the current day, the current day, or the day after the current day,
689 respectively.
<literal>now
</literal> refers to the current time. Finally, relative times may be specified,
690 prefixed with
<literal>-
</literal> or
<literal>+
</literal>, referring to times before or after the current
691 time, respectively. For complete time and date specification, see
692 <citerefentry><refentrytitle>systemd.time
</refentrytitle><manvolnum>7</manvolnum></citerefentry>. Note that
693 <option>--output=short-full
</option> prints timestamps that follow precisely this format.
699 <term><option>-F
</option></term>
700 <term><option>--field=
</option></term>
702 <listitem><para>Print all possible data values the specified
703 field can take in all entries of the journal.
</para></listitem>
707 <term><option>-N
</option></term>
708 <term><option>--fields
</option></term>
710 <listitem><para>Print all field names currently used in all entries of the journal.
</para></listitem>
714 <term><option>--system
</option></term>
715 <term><option>--user
</option></term>
717 <listitem><para>Show messages from system services and the
718 kernel (with
<option>--system
</option>). Show messages from
719 service of current user (with
<option>--user
</option>). If
720 neither is specified, show all messages that the user can see.
725 <term><option>-M
</option></term>
726 <term><option>--machine=
</option></term>
728 <listitem><para>Show messages from a running, local
729 container. Specify a container name to connect to.
</para>
734 <term><option>-D
<replaceable>DIR
</replaceable></option></term>
735 <term><option>--directory=
<replaceable>DIR
</replaceable></option></term>
737 <listitem><para>Takes a directory path as argument. If
738 specified, journalctl will operate on the specified journal
739 directory
<replaceable>DIR
</replaceable> instead of the
740 default runtime and system journal paths.
</para></listitem>
744 <term><option>--file=
<replaceable>GLOB
</replaceable></option></term>
746 <listitem><para>Takes a file glob as an argument. If
747 specified, journalctl will operate on the specified journal
748 files matching
<replaceable>GLOB
</replaceable> instead of the
749 default runtime and system journal paths. May be specified
750 multiple times, in which case files will be suitably
751 interleaved.
</para></listitem>
755 <term><option>--root=
<replaceable>ROOT
</replaceable></option></term>
757 <listitem><para>Takes a directory path as an argument. If
758 specified, journalctl will operate on journal directories and catalog file hierarchy
759 underneath the specified directory instead of the root
760 directory (e.g.
<option>--update-catalog
</option> will create
761 <filename><replaceable>ROOT
</replaceable>/var/lib/systemd/catalog/database
</filename>,
762 and journal files under
<filename><replaceable>ROOT
</replaceable>/run/journal
</filename>
763 or
<filename><replaceable>ROOT
</replaceable>/var/log/journal
</filename> will be displayed).
768 <term><option>--namespace=
<replaceable>NAMESPACE
</replaceable></option></term>
770 <listitem><para>Takes a journal namespace identifier string as argument. If not specified the data
771 collected by the default namespace is shown. If specified shows the log data of the specified
772 namespace instead. If the namespace is specified as
<literal>*
</literal> data from all namespaces is
773 shown, interleaved. If the namespace identifier is prefixed with
<literal>+
</literal> data from the
774 specified namespace and the default namespace is shown, interleaved, but no other. For details about
775 journal namespaces see
776 <citerefentry><refentrytitle>systemd-journald.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para></listitem>
780 <term><option>--header
</option></term>
782 <listitem><para>Instead of showing journal contents, show
783 internal header information of the journal fields
784 accessed.
</para></listitem>
788 <term><option>--disk-usage
</option></term>
790 <listitem><para>Shows the current disk usage of all journal
791 files. This shows the sum of the disk usage of all archived
792 and active journal files.
</para></listitem>
796 <term><option>--vacuum-size=
</option></term>
797 <term><option>--vacuum-time=
</option></term>
798 <term><option>--vacuum-files=
</option></term>
800 <listitem><para>Removes the oldest archived journal files until the disk space they use falls below the
801 specified size (specified with the usual
<literal>K
</literal>,
<literal>M
</literal>,
<literal>G
</literal> and
802 <literal>T
</literal> suffixes), or all archived journal files contain no data older than the specified timespan
803 (specified with the usual
<literal>s
</literal>,
<literal>m
</literal>,
<literal>h
</literal>,
804 <literal>days
</literal>,
<literal>months
</literal>,
<literal>weeks
</literal> and
<literal>years
</literal>
805 suffixes), or no more than the specified number of separate journal files remain. Note that running
806 <option>--vacuum-size=
</option> has only an indirect effect on the output shown by
807 <option>--disk-usage
</option>, as the latter includes active journal files, while the vacuuming operation only
808 operates on archived journal files. Similarly,
<option>--vacuum-files=
</option> might not actually reduce the
809 number of journal files to below the specified number, as it will not remove active journal
812 <para><option>--vacuum-size=
</option>,
<option>--vacuum-time=
</option> and
<option>--vacuum-files=
</option>
813 may be combined in a single invocation to enforce any combination of a size, a time and a number of files limit
814 on the archived journal files. Specifying any of these three parameters as zero is equivalent to not enforcing
815 the specific limit, and is thus redundant.
</para>
817 <para>These three switches may also be combined with
<option>--rotate
</option> into one command. If so, all
818 active files are rotated first, and the requested vacuuming operation is executed right after. The rotation has
819 the effect that all currently active files are archived (and potentially new, empty journal files opened as
820 replacement), and hence the vacuuming operation has the greatest effect as it can take all log data written so
821 far into account.
</para></listitem>
825 <term><option>--list-catalog
826 <optional><replaceable>128-bit-ID…
</replaceable></optional>
829 <listitem><para>List the contents of the message catalog as a
830 table of message IDs, plus their short description strings.
833 <para>If any
<replaceable>128-bit-ID
</replaceable>s are
834 specified, only those entries are shown.
</para>
839 <term><option>--dump-catalog
840 <optional><replaceable>128-bit-ID…
</replaceable></optional>
843 <listitem><para>Show the contents of the message catalog, with
844 entries separated by a line consisting of two dashes and the
845 ID (the format is the same as
<filename>.catalog
</filename>
848 <para>If any
<replaceable>128-bit-ID
</replaceable>s are
849 specified, only those entries are shown.
</para>
854 <term><option>--update-catalog
</option></term>
856 <listitem><para>Update the message catalog index. This command
857 needs to be executed each time new catalog files are
858 installed, removed, or updated to rebuild the binary catalog
859 index.
</para></listitem>
863 <term><option>--setup-keys
</option></term>
865 <listitem><para>Instead of showing journal contents, generate
866 a new key pair for Forward Secure Sealing (FSS). This will
867 generate a sealing key and a verification key. The sealing key
868 is stored in the journal data directory and shall remain on
869 the host. The verification key should be stored
870 externally. Refer to the
<option>Seal=
</option> option in
871 <citerefentry><refentrytitle>journald.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
872 for information on Forward Secure Sealing and for a link to a
873 refereed scholarly paper detailing the cryptographic theory it
874 is based on.
</para></listitem>
878 <term><option>--force
</option></term>
880 <listitem><para>When
<option>--setup-keys
</option> is passed
881 and Forward Secure Sealing (FSS) has already been configured,
882 recreate FSS keys.
</para></listitem>
886 <term><option>--interval=
</option></term>
888 <listitem><para>Specifies the change interval for the sealing
889 key when generating an FSS key pair with
890 <option>--setup-keys
</option>. Shorter intervals increase CPU
891 consumption but shorten the time range of undetectable journal
892 alterations. Defaults to
15min.
</para></listitem>
896 <term><option>--verify
</option></term>
898 <listitem><para>Check the journal file for internal
899 consistency. If the file has been generated with FSS enabled and
900 the FSS verification key has been specified with
901 <option>--verify-key=
</option>, authenticity of the journal file
902 is verified.
</para></listitem>
906 <term><option>--verify-key=
</option></term>
908 <listitem><para>Specifies the FSS verification key to use for
909 the
<option>--verify
</option> operation.
</para></listitem>
913 <term><option>--sync
</option></term>
915 <listitem><para>Asks the journal daemon to write all yet
916 unwritten journal data to the backing file system and
917 synchronize all journals. This call does not return until the
918 synchronization operation is complete. This command guarantees
919 that any log messages written before its invocation are safely
920 stored on disk at the time it returns.
</para></listitem>
924 <term><option>--flush
</option></term>
926 <listitem><para>Asks the journal daemon to flush any log data stored in
927 <filename>/run/log/journal/
</filename> into
<filename>/var/log/journal/
</filename>, if persistent
928 storage is enabled. This call does not return until the operation is complete. Note that this call is
929 idempotent: the data is only flushed from
<filename>/run/log/journal/
</filename> into
930 <filename>/var/log/journal
</filename> once during system runtime (but see
931 <option>--relinquish-var
</option> below), and this command exits cleanly without executing any
932 operation if this has already happened. This command effectively guarantees that all data is flushed
933 to
<filename>/var/log/journal
</filename> at the time it returns.
</para></listitem>
937 <term><option>--relinquish-var
</option></term>
939 <listitem><para>Asks the journal daemon for the reverse operation to
<option>--flush
</option>: if
940 requested the daemon will write further log data to
<filename>/run/log/journal/
</filename> and stops
941 writing to
<filename>/var/log/journal/
</filename>. A subsequent call to
<option>--flush
</option>
942 causes the log output to switch back to
<filename>/var/log/journal/
</filename>, see
943 above.
</para></listitem>
947 <term><option>--smart-relinquish-var
</option></term>
949 <listitem><para>Similar to
<option>--relinquish-var
</option> but executes no operation if the root file
950 system and
<filename>/var/lib/journal/
</filename> reside on the same mount point. This operation is
951 used during system shutdown in order to make the journal daemon stop writing data to
952 <filename>/var/log/journal/
</filename> in case that directory is located on a mount point that needs
953 to be unmounted.
</para></listitem>
957 <term><option>--rotate
</option></term>
959 <listitem><para>Asks the journal daemon to rotate journal files. This call does not return until the rotation
960 operation is complete. Journal file rotation has the effect that all currently active journal files are marked
961 as archived and renamed, so that they are never written to in future. New (empty) journal files are then
962 created in their place. This operation may be combined with
<option>--vacuum-size=
</option>,
963 <option>--vacuum-time=
</option> and
<option>--vacuum-file=
</option> into a single command, see
964 above.
</para></listitem>
967 <xi:include href=
"standard-options.xml" xpointer=
"help" />
968 <xi:include href=
"standard-options.xml" xpointer=
"version" />
969 <xi:include href=
"standard-options.xml" xpointer=
"no-pager" />
974 <title>Exit status
</title>
976 <para>On success,
0 is returned; otherwise, a non-zero failure
977 code is returned.
</para>
980 <xi:include href=
"less-variables.xml" />
983 <title>Examples
</title>
985 <para>Without arguments, all collected logs are shown
988 <programlisting>journalctl
</programlisting>
990 <para>With one match specified, all entries with a field matching
991 the expression are shown:
</para>
993 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service
994 journalctl _SYSTEMD_CGROUP=/user.slice/user-
42.slice/session-c1.scope
</programlisting>
996 <para>If two different fields are matched, only entries matching
997 both expressions at the same time are shown:
</para>
999 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=
28097</programlisting>
1001 <para>If two matches refer to the same field, all entries matching
1002 either expression are shown:
</para>
1004 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service
</programlisting>
1006 <para>If the separator
<literal>+
</literal> is used, two
1007 expressions may be combined in a logical OR. The following will
1008 show all messages from the Avahi service process with the PID
1009 28097 plus all messages from the D-Bus service (from any of its
1012 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=
28097 + _SYSTEMD_UNIT=dbus.service
</programlisting>
1014 <para>To show all fields emitted
<emphasis>by
</emphasis> a unit and
<emphasis>about
</emphasis>
1015 the unit, option
<option>-u
</option>/
<option>--unit=
</option> should be used.
1016 <command>journalctl -u
<replaceable>name
</replaceable></command>
1017 expands to a complex filter similar to
1018 <programlisting>_SYSTEMD_UNIT=
<replaceable>name
</replaceable>.service
1019 + UNIT=
<replaceable>name
</replaceable>.service _PID=
1
1020 + OBJECT_SYSTEMD_UNIT=
<replaceable>name
</replaceable>.service _UID=
0
1021 + COREDUMP_UNIT=
<replaceable>name
</replaceable>.service _UID=
0 MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1
1023 (see
<citerefentry><refentrytitle>systemd.journal-fields
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1024 for an explanation of those patterns).
1027 <para>Show all logs generated by the D-Bus executable:
</para>
1029 <programlisting>journalctl /usr/bin/dbus-daemon
</programlisting>
1031 <para>Show all kernel logs from previous boot:
</para>
1033 <programlisting>journalctl -k -b -
1</programlisting>
1035 <para>Show a live log display from a system service
1036 <filename>apache.service
</filename>:
</para>
1038 <programlisting>journalctl -f -u apache
</programlisting>
1043 <title>See Also
</title>
1045 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1046 <citerefentry><refentrytitle>systemd-journald.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1047 <citerefentry><refentrytitle>systemctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1048 <citerefentry><refentrytitle>coredumpctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1049 <citerefentry><refentrytitle>systemd.journal-fields
</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1050 <citerefentry><refentrytitle>journald.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1051 <citerefentry><refentrytitle>systemd.time
</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1052 <citerefentry><refentrytitle>systemd-journal-remote.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1053 <citerefentry><refentrytitle>systemd-journal-upload.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>