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 actual message of each journal entry
378 with no metadata, not even a timestamp. If combined with the
379 <option>--output-fields=
</option> option will output the listed fields for each log record,
380 instead of the message.
</para>
386 <option>with-unit
</option>
389 <para>similar to short-full, but prefixes the unit and
390 user unit names instead of the traditional syslog
391 identifier. Useful when using templated instances, as it
392 will include the arguments in the unit names.
</para>
400 <term><option>--output-fields=
</option></term>
402 <listitem><para>A comma separated list of the fields which should be included in the output. This has
403 an effect only for the output modes which would normally show all fields (
<option>verbose
</option>,
404 <option>export
</option>,
<option>json
</option>,
<option>json-pretty
</option>,
405 <option>json-sse
</option> and
<option>json-seq
</option>), as well as on
<option>cat
</option>. For the
406 former, the
<literal>__CURSOR
</literal>,
<literal>__REALTIME_TIMESTAMP
</literal>,
407 <literal>__MONOTONIC_TIMESTAMP
</literal>, and
<literal>_BOOT_ID
</literal> fields are always
408 printed.
</para></listitem>
412 <term><option>--utc
</option></term>
414 <listitem><para>Express time in Coordinated Universal Time
415 (UTC).
</para></listitem>
419 <term><option>--no-hostname
</option></term>
421 <listitem><para>Don't show the hostname field of log messages originating from the local host. This
422 switch has an effect only on the
<option>short
</option> family of output modes (see above).
425 <para>Note: this option does not remove occurrences of the hostname from log entries themselves, so
426 it does not prevent the hostname from being visible in the logs.
</para>
431 <term><option>-x
</option></term>
432 <term><option>--catalog
</option></term>
434 <listitem><para>Augment log lines with explanation texts from
435 the message catalog. This will add explanatory help texts to
436 log messages in the output where this is available. These
437 short help texts will explain the context of an error or log
438 event, possible solutions, as well as pointers to support
439 forums, developer documentation, and any other relevant
440 manuals. Note that help texts are not available for all
441 messages, but only for selected ones. For more information on
442 the message catalog, please refer to the
443 <ulink url=
"https://www.freedesktop.org/wiki/Software/systemd/catalog">Message Catalog Developer Documentation
</ulink>.
</para>
445 <para>Note: when attaching
<command>journalctl
</command>
446 output to bug reports, please do
<emphasis>not
</emphasis> use
447 <option>-x
</option>.
</para>
452 <term><option>-q
</option></term>
453 <term><option>--quiet
</option></term>
455 <listitem><para>Suppresses all informational messages
456 (i.e.
"-- Logs begin at …",
"-- Reboot --"),
457 any warning messages regarding
458 inaccessible system journals when run as a normal
459 user.
</para></listitem>
463 <term><option>-m
</option></term>
464 <term><option>--merge
</option></term>
466 <listitem><para>Show entries interleaved from all available
467 journals, including remote ones.
</para></listitem>
471 <term><option>-b
<optional><optional><replaceable>ID
</replaceable></optional><optional><replaceable>±offset
</replaceable></optional>|
<constant>all
</constant></optional></option></term>
472 <term><option>--boot
<optional>=
<optional><replaceable>ID
</replaceable></optional><optional><replaceable>±offset
</replaceable></optional>|
<constant>all
</constant></optional></option></term>
474 <listitem><para>Show messages from a specific boot. This will
475 add a match for
<literal>_BOOT_ID=
</literal>.
</para>
477 <para>The argument may be empty, in which case logs for the
478 current boot will be shown.
</para>
480 <para>If the boot ID is omitted, a positive
481 <replaceable>offset
</replaceable> will look up the boots
482 starting from the beginning of the journal, and an
483 equal-or-less-than zero
<replaceable>offset
</replaceable> will
484 look up boots starting from the end of the journal. Thus,
485 <constant>1</constant> means the first boot found in the
486 journal in chronological order,
<constant>2</constant> the
487 second and so on; while
<constant>-
0</constant> is the last
488 boot,
<constant>-
1</constant> the boot before last, and so
489 on. An empty
<replaceable>offset
</replaceable> is equivalent
490 to specifying
<constant>-
0</constant>, except when the current
491 boot is not the last boot (e.g. because
492 <option>--directory
</option> was specified to look at logs
493 from a different machine).
</para>
495 <para>If the
32-character
<replaceable>ID
</replaceable> is
496 specified, it may optionally be followed by
497 <replaceable>offset
</replaceable> which identifies the boot
498 relative to the one given by boot
499 <replaceable>ID
</replaceable>. Negative values mean earlier
500 boots and positive values mean later boots. If
501 <replaceable>offset
</replaceable> is not specified, a value of
502 zero is assumed, and the logs for the boot given by
503 <replaceable>ID
</replaceable> are shown.
</para>
505 <para>The special argument
<constant>all
</constant> can be
506 used to negate the effect of an earlier use of
507 <option>-b
</option>.
</para>
512 <term><option>--list-boots
</option></term>
514 <listitem><para>Show a tabular list of boot numbers (relative to
515 the current boot), their IDs, and the timestamps of the first
516 and last message pertaining to the boot.
</para></listitem>
520 <term><option>-k
</option></term>
521 <term><option>--dmesg
</option></term>
523 <listitem><para>Show only kernel messages. This implies
524 <option>-b
</option> and adds the match
525 <literal>_TRANSPORT=kernel
</literal>.
</para></listitem>
529 <term><option>-t
</option></term>
530 <term><option>--identifier=
<replaceable>SYSLOG_IDENTIFIER
</replaceable></option></term>
532 <listitem><para>Show messages for the specified syslog
534 <replaceable>SYSLOG_IDENTIFIER
</replaceable>.
</para>
536 <para>This parameter can be specified multiple
537 times.
</para></listitem>
541 <term><option>-u
</option></term>
542 <term><option>--unit=
<replaceable>UNIT
</replaceable>|
<replaceable>PATTERN
</replaceable></option></term>
544 <listitem><para>Show messages for the specified systemd unit
545 <replaceable>UNIT
</replaceable> (such as a service unit), or
546 for any of the units matched by
547 <replaceable>PATTERN
</replaceable>. If a pattern is
548 specified, a list of unit names found in the journal is
549 compared with the specified pattern and all that match are
550 used. For each unit name, a match is added for messages from
552 (
<literal>_SYSTEMD_UNIT=
<replaceable>UNIT
</replaceable></literal>),
553 along with additional matches for messages from systemd and
554 messages about coredumps for the specified unit. A match
555 is also added for
<literal>_SYSTEMD_SLICE=
<replaceable>UNIT
</replaceable></literal>,
556 such that if the provided
<replaceable>UNIT
</replaceable> is a
557 <citerefentry><refentrytitle>systemd.slice
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
558 unit, all logs of the children of the slice will be logged.
561 <para>This parameter can be specified multiple times.
</para>
566 <term><option>--user-unit=
</option></term>
568 <listitem><para>Show messages for the specified user session
569 unit. This will add a match for messages from the unit
570 (
<literal>_SYSTEMD_USER_UNIT=
</literal> and
571 <literal>_UID=
</literal>) and additional matches for messages
572 from session systemd and messages about coredumps for the
573 specified unit. A match
574 is also added for
<literal>_SYSTEMD_USER_SLICE=
<replaceable>UNIT
</replaceable></literal>,
575 such that if the provided
<replaceable>UNIT
</replaceable> is a
576 <citerefentry><refentrytitle>systemd.slice
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
577 unit, all logs of the children of the unit will be logged.
</para>
579 <para>This parameter can be specified multiple times.
</para>
584 <term><option>-p
</option></term>
585 <term><option>--priority=
</option></term>
587 <listitem><para>Filter output by message priorities or
588 priority ranges. Takes either a single numeric or textual log
589 level (i.e. between
0/
<literal>emerg
</literal> and
590 7/
<literal>debug
</literal>), or a range of numeric/text log
591 levels in the form FROM..TO. The log levels are the usual
592 syslog log levels as documented in
593 <citerefentry project='man-pages'
><refentrytitle>syslog
</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
594 i.e.
<literal>emerg
</literal>Â (
0),
595 <literal>alert
</literal>Â (
1),
<literal>crit
</literal>Â (
2),
596 <literal>err
</literal>Â (
3),
<literal>warning
</literal>Â (
4),
597 <literal>notice
</literal>Â (
5),
<literal>info
</literal>Â (
6),
598 <literal>debug
</literal>Â (
7). If a single log level is
599 specified, all messages with this log level or a lower (hence
600 more important) log level are shown. If a range is specified,
601 all messages within the range are shown, including both the
602 start and the end value of the range. This will add
603 <literal>PRIORITY=
</literal> matches for the specified
604 priorities.
</para></listitem>
608 <term><option>--facility=
</option></term>
610 <listitem><para>Filter output by syslog facility. Takes a comma-separated list of numbers or facility
611 names. The names are the usual syslog facilities as documented in
612 <citerefentry project='man-pages'
><refentrytitle>syslog
</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
613 <option>--facility=help
</option> may be used to display a list of known facility names and exit.
618 <term><option>-g
</option></term>
619 <term><option>--grep=
</option></term>
621 <listitem><para>Filter output to entries where the
<varname>MESSAGE=
</varname>
622 field matches the specified regular expression. PERL-compatible regular expressions
624 <citerefentry><refentrytitle>pcre2pattern
</refentrytitle><manvolnum>3</manvolnum></citerefentry>
625 for a detailed description of the syntax.
</para>
627 <para>If the pattern is all lowercase, matching is case insensitive.
628 Otherwise, matching is case sensitive. This can be overridden with the
629 <option>--case-sensitive
</option> option, see below.
</para>
634 <term><option>--case-sensitive
<optional>=BOOLEAN
</optional></option></term>
636 <listitem><para>Make pattern matching case sensitive or case insensitive.
</para>
641 <term><option>-c
</option></term>
642 <term><option>--cursor=
</option></term>
644 <listitem><para>Start showing entries from the location in the
645 journal specified by the passed cursor.
</para></listitem>
649 <term><option>--cursor-file=
<replaceable>FILE
</replaceable></option></term>
651 <listitem><para>If
<replaceable>FILE
</replaceable> exists and contains a
652 cursor, start showing entries
<emphasis>after
</emphasis> this location.
653 Otherwise the show entries according the other given options. At the end,
654 write the cursor of the last entry to
<replaceable>FILE
</replaceable>. Use
655 this option to continually read the journal by sequentially calling
656 <command>journalctl
</command>.
</para></listitem>
660 <term><option>--after-cursor=
</option></term>
662 <listitem><para>Start showing entries from the location in the
663 journal
<emphasis>after
</emphasis> the location specified by
664 the passed cursor. The cursor is shown when the
665 <option>--show-cursor
</option> option is used.
</para>
670 <term><option>--show-cursor
</option></term>
672 <listitem><para>The cursor is shown after the last entry after
674 <programlisting>-- cursor: s=
0639…
</programlisting>
675 <para>The format of the cursor is private
676 and subject to change.
</para></listitem>
680 <term><option>-S
</option></term>
681 <term><option>--since=
</option></term>
682 <term><option>-U
</option></term>
683 <term><option>--until=
</option></term>
685 <listitem><para>Start showing entries on or newer than the specified date, or on or older than the specified
686 date, respectively. Date specifications should be of the format
<literal>2012-
10-
30 18:
17:
16</literal>. If the
687 time part is omitted,
<literal>00:
00:
00</literal> is assumed. If only the seconds component is omitted,
688 <literal>:
00</literal> is assumed. If the date component is omitted, the current day is assumed. Alternatively
689 the strings
<literal>yesterday
</literal>,
<literal>today
</literal>,
<literal>tomorrow
</literal> are understood,
690 which refer to
00:
00:
00 of the day before the current day, the current day, or the day after the current day,
691 respectively.
<literal>now
</literal> refers to the current time. Finally, relative times may be specified,
692 prefixed with
<literal>-
</literal> or
<literal>+
</literal>, referring to times before or after the current
693 time, respectively. For complete time and date specification, see
694 <citerefentry><refentrytitle>systemd.time
</refentrytitle><manvolnum>7</manvolnum></citerefentry>. Note that
695 <option>--output=short-full
</option> prints timestamps that follow precisely this format.
701 <term><option>-F
</option></term>
702 <term><option>--field=
</option></term>
704 <listitem><para>Print all possible data values the specified
705 field can take in all entries of the journal.
</para></listitem>
709 <term><option>-N
</option></term>
710 <term><option>--fields
</option></term>
712 <listitem><para>Print all field names currently used in all entries of the journal.
</para></listitem>
716 <term><option>--system
</option></term>
717 <term><option>--user
</option></term>
719 <listitem><para>Show messages from system services and the
720 kernel (with
<option>--system
</option>). Show messages from
721 service of current user (with
<option>--user
</option>). If
722 neither is specified, show all messages that the user can see.
727 <term><option>-M
</option></term>
728 <term><option>--machine=
</option></term>
730 <listitem><para>Show messages from a running, local
731 container. Specify a container name to connect to.
</para>
736 <term><option>-D
<replaceable>DIR
</replaceable></option></term>
737 <term><option>--directory=
<replaceable>DIR
</replaceable></option></term>
739 <listitem><para>Takes a directory path as argument. If
740 specified, journalctl will operate on the specified journal
741 directory
<replaceable>DIR
</replaceable> instead of the
742 default runtime and system journal paths.
</para></listitem>
746 <term><option>--file=
<replaceable>GLOB
</replaceable></option></term>
748 <listitem><para>Takes a file glob as an argument. If
749 specified, journalctl will operate on the specified journal
750 files matching
<replaceable>GLOB
</replaceable> instead of the
751 default runtime and system journal paths. May be specified
752 multiple times, in which case files will be suitably
753 interleaved.
</para></listitem>
757 <term><option>--root=
<replaceable>ROOT
</replaceable></option></term>
759 <listitem><para>Takes a directory path as an argument. If
760 specified, journalctl will operate on journal directories and catalog file hierarchy
761 underneath the specified directory instead of the root
762 directory (e.g.
<option>--update-catalog
</option> will create
763 <filename><replaceable>ROOT
</replaceable>/var/lib/systemd/catalog/database
</filename>,
764 and journal files under
<filename><replaceable>ROOT
</replaceable>/run/journal
</filename>
765 or
<filename><replaceable>ROOT
</replaceable>/var/log/journal
</filename> will be displayed).
770 <term><option>--namespace=
<replaceable>NAMESPACE
</replaceable></option></term>
772 <listitem><para>Takes a journal namespace identifier string as argument. If not specified the data
773 collected by the default namespace is shown. If specified shows the log data of the specified
774 namespace instead. If the namespace is specified as
<literal>*
</literal> data from all namespaces is
775 shown, interleaved. If the namespace identifier is prefixed with
<literal>+
</literal> data from the
776 specified namespace and the default namespace is shown, interleaved, but no other. For details about
777 journal namespaces see
778 <citerefentry><refentrytitle>systemd-journald.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
</para></listitem>
782 <term><option>--header
</option></term>
784 <listitem><para>Instead of showing journal contents, show
785 internal header information of the journal fields
786 accessed.
</para></listitem>
790 <term><option>--disk-usage
</option></term>
792 <listitem><para>Shows the current disk usage of all journal
793 files. This shows the sum of the disk usage of all archived
794 and active journal files.
</para></listitem>
798 <term><option>--vacuum-size=
</option></term>
799 <term><option>--vacuum-time=
</option></term>
800 <term><option>--vacuum-files=
</option></term>
802 <listitem><para>Removes the oldest archived journal files until the disk space they use falls below the
803 specified size (specified with the usual
<literal>K
</literal>,
<literal>M
</literal>,
<literal>G
</literal> and
804 <literal>T
</literal> suffixes), or all archived journal files contain no data older than the specified timespan
805 (specified with the usual
<literal>s
</literal>,
<literal>m
</literal>,
<literal>h
</literal>,
806 <literal>days
</literal>,
<literal>months
</literal>,
<literal>weeks
</literal> and
<literal>years
</literal>
807 suffixes), or no more than the specified number of separate journal files remain. Note that running
808 <option>--vacuum-size=
</option> has only an indirect effect on the output shown by
809 <option>--disk-usage
</option>, as the latter includes active journal files, while the vacuuming operation only
810 operates on archived journal files. Similarly,
<option>--vacuum-files=
</option> might not actually reduce the
811 number of journal files to below the specified number, as it will not remove active journal
814 <para><option>--vacuum-size=
</option>,
<option>--vacuum-time=
</option> and
<option>--vacuum-files=
</option>
815 may be combined in a single invocation to enforce any combination of a size, a time and a number of files limit
816 on the archived journal files. Specifying any of these three parameters as zero is equivalent to not enforcing
817 the specific limit, and is thus redundant.
</para>
819 <para>These three switches may also be combined with
<option>--rotate
</option> into one command. If so, all
820 active files are rotated first, and the requested vacuuming operation is executed right after. The rotation has
821 the effect that all currently active files are archived (and potentially new, empty journal files opened as
822 replacement), and hence the vacuuming operation has the greatest effect as it can take all log data written so
823 far into account.
</para></listitem>
827 <term><option>--list-catalog
828 <optional><replaceable>128-bit-ID…
</replaceable></optional>
831 <listitem><para>List the contents of the message catalog as a
832 table of message IDs, plus their short description strings.
835 <para>If any
<replaceable>128-bit-ID
</replaceable>s are
836 specified, only those entries are shown.
</para>
841 <term><option>--dump-catalog
842 <optional><replaceable>128-bit-ID…
</replaceable></optional>
845 <listitem><para>Show the contents of the message catalog, with
846 entries separated by a line consisting of two dashes and the
847 ID (the format is the same as
<filename>.catalog
</filename>
850 <para>If any
<replaceable>128-bit-ID
</replaceable>s are
851 specified, only those entries are shown.
</para>
856 <term><option>--update-catalog
</option></term>
858 <listitem><para>Update the message catalog index. This command
859 needs to be executed each time new catalog files are
860 installed, removed, or updated to rebuild the binary catalog
861 index.
</para></listitem>
865 <term><option>--setup-keys
</option></term>
867 <listitem><para>Instead of showing journal contents, generate
868 a new key pair for Forward Secure Sealing (FSS). This will
869 generate a sealing key and a verification key. The sealing key
870 is stored in the journal data directory and shall remain on
871 the host. The verification key should be stored
872 externally. Refer to the
<option>Seal=
</option> option in
873 <citerefentry><refentrytitle>journald.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
874 for information on Forward Secure Sealing and for a link to a
875 refereed scholarly paper detailing the cryptographic theory it
876 is based on.
</para></listitem>
880 <term><option>--force
</option></term>
882 <listitem><para>When
<option>--setup-keys
</option> is passed
883 and Forward Secure Sealing (FSS) has already been configured,
884 recreate FSS keys.
</para></listitem>
888 <term><option>--interval=
</option></term>
890 <listitem><para>Specifies the change interval for the sealing
891 key when generating an FSS key pair with
892 <option>--setup-keys
</option>. Shorter intervals increase CPU
893 consumption but shorten the time range of undetectable journal
894 alterations. Defaults to
15min.
</para></listitem>
898 <term><option>--verify
</option></term>
900 <listitem><para>Check the journal file for internal
901 consistency. If the file has been generated with FSS enabled and
902 the FSS verification key has been specified with
903 <option>--verify-key=
</option>, authenticity of the journal file
904 is verified.
</para></listitem>
908 <term><option>--verify-key=
</option></term>
910 <listitem><para>Specifies the FSS verification key to use for
911 the
<option>--verify
</option> operation.
</para></listitem>
915 <term><option>--sync
</option></term>
917 <listitem><para>Asks the journal daemon to write all yet
918 unwritten journal data to the backing file system and
919 synchronize all journals. This call does not return until the
920 synchronization operation is complete. This command guarantees
921 that any log messages written before its invocation are safely
922 stored on disk at the time it returns.
</para></listitem>
926 <term><option>--flush
</option></term>
928 <listitem><para>Asks the journal daemon to flush any log data stored in
929 <filename>/run/log/journal/
</filename> into
<filename>/var/log/journal/
</filename>, if persistent
930 storage is enabled. This call does not return until the operation is complete. Note that this call is
931 idempotent: the data is only flushed from
<filename>/run/log/journal/
</filename> into
932 <filename>/var/log/journal
</filename> once during system runtime (but see
933 <option>--relinquish-var
</option> below), and this command exits cleanly without executing any
934 operation if this has already happened. This command effectively guarantees that all data is flushed
935 to
<filename>/var/log/journal
</filename> at the time it returns.
</para></listitem>
939 <term><option>--relinquish-var
</option></term>
941 <listitem><para>Asks the journal daemon for the reverse operation to
<option>--flush
</option>: if
942 requested the daemon will write further log data to
<filename>/run/log/journal/
</filename> and stops
943 writing to
<filename>/var/log/journal/
</filename>. A subsequent call to
<option>--flush
</option>
944 causes the log output to switch back to
<filename>/var/log/journal/
</filename>, see
945 above.
</para></listitem>
949 <term><option>--smart-relinquish-var
</option></term>
951 <listitem><para>Similar to
<option>--relinquish-var
</option> but executes no operation if the root file
952 system and
<filename>/var/lib/journal/
</filename> reside on the same mount point. This operation is
953 used during system shutdown in order to make the journal daemon stop writing data to
954 <filename>/var/log/journal/
</filename> in case that directory is located on a mount point that needs
955 to be unmounted.
</para></listitem>
959 <term><option>--rotate
</option></term>
961 <listitem><para>Asks the journal daemon to rotate journal files. This call does not return until the rotation
962 operation is complete. Journal file rotation has the effect that all currently active journal files are marked
963 as archived and renamed, so that they are never written to in future. New (empty) journal files are then
964 created in their place. This operation may be combined with
<option>--vacuum-size=
</option>,
965 <option>--vacuum-time=
</option> and
<option>--vacuum-file=
</option> into a single command, see
966 above.
</para></listitem>
969 <xi:include href=
"standard-options.xml" xpointer=
"help" />
970 <xi:include href=
"standard-options.xml" xpointer=
"version" />
971 <xi:include href=
"standard-options.xml" xpointer=
"no-pager" />
976 <title>Exit status
</title>
978 <para>On success,
0 is returned; otherwise, a non-zero failure
979 code is returned.
</para>
982 <xi:include href=
"less-variables.xml" />
985 <title>Examples
</title>
987 <para>Without arguments, all collected logs are shown
990 <programlisting>journalctl
</programlisting>
992 <para>With one match specified, all entries with a field matching
993 the expression are shown:
</para>
995 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service
996 journalctl _SYSTEMD_CGROUP=/user.slice/user-
42.slice/session-c1.scope
</programlisting>
998 <para>If two different fields are matched, only entries matching
999 both expressions at the same time are shown:
</para>
1001 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=
28097</programlisting>
1003 <para>If two matches refer to the same field, all entries matching
1004 either expression are shown:
</para>
1006 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service
</programlisting>
1008 <para>If the separator
<literal>+
</literal> is used, two
1009 expressions may be combined in a logical OR. The following will
1010 show all messages from the Avahi service process with the PID
1011 28097 plus all messages from the D-Bus service (from any of its
1014 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=
28097 + _SYSTEMD_UNIT=dbus.service
</programlisting>
1016 <para>To show all fields emitted
<emphasis>by
</emphasis> a unit and
<emphasis>about
</emphasis>
1017 the unit, option
<option>-u
</option>/
<option>--unit=
</option> should be used.
1018 <command>journalctl -u
<replaceable>name
</replaceable></command>
1019 expands to a complex filter similar to
1020 <programlisting>_SYSTEMD_UNIT=
<replaceable>name
</replaceable>.service
1021 + UNIT=
<replaceable>name
</replaceable>.service _PID=
1
1022 + OBJECT_SYSTEMD_UNIT=
<replaceable>name
</replaceable>.service _UID=
0
1023 + COREDUMP_UNIT=
<replaceable>name
</replaceable>.service _UID=
0 MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1
1025 (see
<citerefentry><refentrytitle>systemd.journal-fields
</refentrytitle><manvolnum>5</manvolnum></citerefentry>
1026 for an explanation of those patterns).
1029 <para>Show all logs generated by the D-Bus executable:
</para>
1031 <programlisting>journalctl /usr/bin/dbus-daemon
</programlisting>
1033 <para>Show all kernel logs from previous boot:
</para>
1035 <programlisting>journalctl -k -b -
1</programlisting>
1037 <para>Show a live log display from a system service
1038 <filename>apache.service
</filename>:
</para>
1040 <programlisting>journalctl -f -u apache
</programlisting>
1045 <title>See Also
</title>
1047 <citerefentry><refentrytitle>systemd
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1048 <citerefentry><refentrytitle>systemd-journald.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1049 <citerefentry><refentrytitle>systemctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1050 <citerefentry><refentrytitle>coredumpctl
</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
1051 <citerefentry><refentrytitle>systemd.journal-fields
</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1052 <citerefentry><refentrytitle>journald.conf
</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
1053 <citerefentry><refentrytitle>systemd.time
</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
1054 <citerefentry><refentrytitle>systemd-journal-remote.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
1055 <citerefentry><refentrytitle>systemd-journal-upload.service
</refentrytitle><manvolnum>8</manvolnum></citerefentry>