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6 This file is part of systemd.
8 Copyright 2012 Lennart Poettering
10 systemd is free software; you can redistribute it and/or modify it
11 under the terms of the GNU Lesser General Public License as published by
12 the Free Software Foundation; either version 2.1 of the License, or
13 (at your option) any later version.
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24 <refentry id="journalctl">
27 <title>journalctl</title>
28 <productname>systemd</productname>
32 <contrib>Developer</contrib>
33 <firstname>Lennart</firstname>
34 <surname>Poettering</surname>
35 <email>lennart@poettering.net</email>
41 <refentrytitle>journalctl</refentrytitle>
42 <manvolnum>1</manvolnum>
46 <refname>journalctl</refname>
47 <refpurpose>Query the systemd journal</refpurpose>
52 <command>journalctl <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt" rep="repeat">MATCHES</arg></command>
57 <title>Description</title>
59 <para><command>journalctl</command> may be used to
60 query the contents of the
61 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
63 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
65 <para>If called without parameter it will show the full
66 contents of the journal, starting with the oldest
67 entry collected.</para>
69 <para>If one or more match arguments are passed the
70 output is filtered accordingly. A match is in the
71 format <literal>FIELD=VALUE</literal>,
72 e.g. <literal>_SYSTEMD_UNIT=httpd.service</literal>,
73 referring to the components of a structured journal
75 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
76 for a list of well-known fields. If multiple matches
77 are specified matching different fields the log
78 entries are filtered by both, i.e. the resulting output
79 will show only entries matching all the specified
80 matches of this kind. If two matches apply to the same
81 field, then they are automatically matched as
82 alternatives, i.e. the resulting output will show
83 entries matching any of the specified matches for the
84 same field. Finally, if the character
85 "<literal>+</literal>" appears as separate word on the
86 command line all matches before and after are combined
87 in a disjunction (i.e. logical OR).</para>
89 <para>As shortcuts for a few types of field/value
90 matches file paths may be specified. If a file path
91 refers to an executable file, this is equivalent to an
92 <literal>_EXE=</literal> match for the canonicalized
93 binary path. Similar, if a path refers to a device
94 node, this is equivalent to a
95 <literal>_KERNEL_DEVICE=</literal> match for the
98 <para>Output is interleaved from all accessible
99 journal files, whether they are rotated or currently
100 being written, and regardless whether they belong to the
101 system itself or are accessible user journals.</para>
103 <para>All users are granted access to their private
104 per-user journals. However, by default only root and
105 users who are members of the <literal>adm</literal>
106 group get access to the system journal and the
107 journals of other users.</para>
111 <title>Options</title>
113 <para>The following options are understood:</para>
117 <term><option>-h</option></term>
118 <term><option>--help</option></term>
120 <listitem><para>Prints a short help
121 text and exits.</para></listitem>
125 <term><option>--version</option></term>
127 <listitem><para>Prints a short version
128 string and exits.</para></listitem>
132 <term><option>--no-pager</option></term>
134 <listitem><para>Do not pipe output into a
135 pager.</para></listitem>
139 <term><option>--full</option></term>
141 <listitem><para>Show all (printable) fields in
142 full.</para></listitem>
146 <term><option>-a</option></term>
147 <term><option>--all</option></term>
149 <listitem><para>Show all fields in
150 full, even if they include unprintable
151 characters or are very
152 long.</para></listitem>
156 <term><option>-f</option></term>
157 <term><option>--follow</option></term>
159 <listitem><para>Show only the most recent
160 journal entries, and continuously print
161 new entries as they are appended to
162 the journal.</para></listitem>
166 <term><option>-e</option></term>
167 <term><option>--pager-end</option></term>
169 <listitem><para>Immediately jump to
170 the end of the journal inside the
171 implied pager tool. Very useful in
173 <option>-b</option> option. Note that
174 this is only supported for the
175 <citerefentry><refentrytitle>less</refentrytitle><manvolnum>1</manvolnum></citerefentry>
176 pager.</para></listitem>
180 <term><option>-n</option></term>
181 <term><option>--lines=</option></term>
183 <listitem><para>Show the most recent
184 journal events and limit the number of
186 <option>--follow</option> is used,
187 this option is implied. The argument,
188 a positive integer, is optional, and
189 defaults to 10. </para></listitem>
193 <term><option>--no-tail</option></term>
195 <listitem><para>Show all stored output
196 lines, even in follow mode. Undoes the
198 <option>--lines=</option>.</para></listitem>
202 <term><option>-r</option></term>
203 <term><option>--reverse</option></term>
205 <listitem><para>Reverse output, so the newest
206 entries are displayed first.</para></listitem>
210 <term><option>-o</option></term>
211 <term><option>--output=</option></term>
213 <listitem><para>Controls the
214 formatting of the journal entries that
215 are shown. Takes one of
216 <literal>short</literal>,
217 <literal>short-monotonic</literal>,
218 <literal>verbose</literal>,
219 <literal>export</literal>,
220 <literal>json</literal>,
221 <literal>json-pretty</literal>,
222 <literal>json-sse</literal>,
223 <literal>cat</literal>. <literal>short</literal>
224 is the default and generates an output
225 that is mostly identical to the
226 formatting of classic syslog log
227 files, showing one line per journal
228 entry. <literal>short-monotonic</literal>
229 is very similar but shows monotonic
230 timestamps instead of wallclock
231 timestamps. <literal>verbose</literal>
232 shows the full structured entry items
234 fields. <literal>export</literal>
235 serializes the journal into a binary
236 (but mostly text-based) stream
237 suitable for backups and network
239 url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal
240 Export Format</ulink> for more
241 information). <literal>json</literal>
242 formats entries as JSON data
245 url="http://www.freedesktop.org/wiki/Software/systemd/json">Journal
246 JSON Format</ulink> for more
247 information). <literal>json-pretty</literal>
248 also formats entries as JSON data
249 structures, but formats them in
250 multiple lines in order to make them
252 humans. <literal>json-sse</literal>
253 also formats entries as JSON data
254 structures, but wraps them in a format
256 url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent
257 Events</ulink>. <literal>cat</literal>
258 generates a very terse output only
259 showing the actual message of each
260 journal entry with no meta data, not
261 even a timestamp.</para></listitem>
265 <term><option>-x</option></term>
266 <term><option>--catalog</option></term>
268 <listitem><para>Augment log lines with
269 explanation texts from the message
270 catalog. This will add explanatory
271 help texts to log messages in the
272 output where this is available. These
273 short help texts will explain the
274 context of an error or log event,
275 possible solutions, as well as
276 pointers to support forums, developer
277 documentation and any other relevant
278 manuals. Note that help texts are not
279 available for all messages, but only
280 for selected ones. For more
281 information on the message catalog
282 please refer to the <ulink
283 url="http://www.freedesktop.org/wiki/Software/systemd/catalog">Message
285 Documentation</ulink>.</para></listitem>
289 <term><option>-q</option></term>
290 <term><option>--quiet</option></term>
292 <listitem><para>Suppresses any warning
293 message regarding inaccessible system
294 journals when run as normal
295 user.</para></listitem>
299 <term><option>-m</option></term>
300 <term><option>--merge</option></term>
302 <listitem><para>Show entries
303 interleaved from all available
304 journals, including remote
305 ones.</para></listitem>
309 <term><option>-b</option></term>
310 <term><option>--this-boot</option></term>
312 <listitem><para>Show data only from
313 current boot. This will add a match
314 for <literal>_BOOT_ID=</literal> for
315 the current boot ID of the
316 kernel.</para></listitem>
320 <term><option>-u</option></term>
321 <term><option>--unit=</option></term>
323 <listitem><para>Show data only of the
324 specified unit. This will add a match
325 for <literal>_SYSTEMD_UNIT=</literal>
327 unit.</para></listitem>
331 <term><option>--user-unit=</option></term>
333 <listitem><para>Show data only of the
334 specified user session unit. This will
336 <literal>_SYSTEMD_USER_UNIT=</literal>
338 unit.</para></listitem>
342 <term><option>-p</option></term>
343 <term><option>--priority=</option></term>
345 <listitem><para>Filter output by
346 message priorities or priority
347 ranges. Takes either a single numeric
348 or textual log level (i.e. between
349 0/<literal>emerg</literal> and
350 7/<literal>debug</literal>), or a
351 range of numeric/text log levels in
352 the form FROM..TO. The log levels are
353 the usual syslog log levels as
355 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
356 i.e. <literal>emerg</literal> (0),
357 <literal>alert</literal> (1),
358 <literal>crit</literal> (2),
359 <literal>err</literal> (3),
360 <literal>warning</literal> (4),
361 <literal>notice</literal> (5),
362 <literal>info</literal> (6),
363 <literal>debug</literal> (7). If a
364 single log level is specified all
365 messages with this log level or a
366 lower (hence more important) log level
367 are shown. If a range is specified all
368 messages within the range are shown,
369 including both the start and the end
370 value of the range. This will add
371 <literal>PRIORITY=</literal> matches
373 priorities.</para></listitem>
377 <term><option>-c</option></term>
378 <term><option>--cursor=</option></term>
380 <listitem><para>Start showing entries
381 from the location in the journal
382 specified by the passed
383 cursor.</para></listitem>
387 <term><option>--since=</option></term>
388 <term><option>--until=</option></term>
390 <listitem><para>Start showing entries
391 on or newer than the specified date,
392 or on or older than the specified
393 date, respectively. Date specifications should be of
394 the format "2012-10-30 18:17:16". If
395 the time part is omitted, 00:00:00 is
396 assumed. If only the seconds component
397 is omitted, :00 is assumed. If the
398 date component is omitted, the
399 current day is assumed. Alternatively
401 <literal>yesterday</literal>,
402 <literal>today</literal>,
403 <literal>tomorrow</literal> are
404 understood, which refer to 00:00:00 of
405 the day before the current day, the
406 current day, or the day after the
407 current day, respectively. <literal>now</literal>
408 refers to the current time. Finally,
409 relative times may be specified,
410 prefixed with <literal>-</literal> or
411 <literal>+</literal>, referring to
412 times before or after the current
413 time, respectively.</para></listitem>
417 <term><option>-F</option></term>
418 <term><option>--field=</option></term>
420 <listitem><para>Print all possible
421 data values the specified field can
422 take in all entries of the
423 journal.</para></listitem>
427 <term><option>-D</option></term>
428 <term><option>--directory=</option></term>
430 <listitem><para>Takes an absolute
431 directory path as argument. If
432 specified journalctl will operate on the
433 specified journal directory instead of
434 the default runtime and system journal
435 paths.</para></listitem>
439 <term><option>--new-id128</option></term>
441 <listitem><para>Instead of showing
442 journal contents generate a new 128
443 bit ID suitable for identifying
444 messages. This is intended for usage
445 by developers who need a new
446 identifier for a new message they
447 introduce and want to make
448 recognizable. Will print the new ID in
449 three different formats which can be
450 copied into source code or
451 similar.</para></listitem>
455 <term><option>--header</option></term>
457 <listitem><para>Instead of showing
458 journal contents show internal header
459 information of the journal fields
460 accessed.</para></listitem>
464 <term><option>--disk-usage</option></term>
466 <listitem><para>Shows the current disk
468 journal files.</para></listitem>
472 <term><option>--list-catalog</option></term>
474 <listitem><para>List the contents of
475 the message catalog, as table of
476 message IDs plus their short
477 description strings.</para></listitem>
481 <term><option>--update-catalog</option></term>
483 <listitem><para>Update the message
484 catalog index. This command needs to
485 be executed each time new catalog
486 files are installed, removed or
487 updated to rebuild the binary catalog
488 index.</para></listitem>
492 <term><option>--setup-keys</option></term>
494 <listitem><para>Instead of showing
495 journal contents generate a new key
496 pair for Forward Secure Sealing
497 (FSS). This will generate a sealing
498 key and a verification key. The
499 sealing key is stored in the journal
500 data directory and shall remain on the
501 host. The verification key should be
502 stored externally.</para></listitem>
506 <term><option>--interval=</option></term>
508 <listitem><para>Specifies the change
509 interval for the sealing key, when
510 generating an FSS key pair with
511 <option>--setup-keys</option>. Shorter
512 intervals increase CPU consumption but
513 shorten the time range of
515 alterations. Defaults to
516 15min.</para></listitem>
520 <term><option>--verify</option></term>
522 <listitem><para>Check the journal file
523 for internal consistency. If the
524 file has been generated with FSS
525 enabled, and the FSS verification key
526 has been specified with
527 <option>--verify-key=</option>
528 authenticity of the journal file is
529 verified.</para></listitem>
533 <term><option>--verify-key=</option></term>
535 <listitem><para>Specifies the FSS
536 verification key to use for the
537 <option>--verify</option>
538 operation.</para></listitem>
545 <title>Exit status</title>
547 <para>On success 0 is returned, a non-zero failure
548 code otherwise.</para>
552 <title>Environment</title>
554 <variablelist class='environment-variables'>
556 <term><varname>$SYSTEMD_PAGER</varname></term>
557 <listitem><para>Pager to use when
558 <option>--no-pager</option> is not given;
559 overrides <varname>$PAGER</varname>. Setting
560 this to an empty string or the value
561 <literal>cat</literal> is equivalent to passing
562 <option>--no-pager</option>.</para></listitem>
568 <title>Examples</title>
570 <para>Without arguments all collected logs are shown
573 <programlisting>journalctl</programlisting>
575 <para>With one match specified all entries with a field matching the expression are shown:</para>
577 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
579 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
581 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
583 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
585 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
587 <para>If the separator "<literal>+</literal>" is used
588 two expressions may be combined in a logical OR. The
589 following will show all messages from the Avahi
590 service process with the PID 28097 plus all messages
591 from the D-Bus service (from any of its
594 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
596 <para>Show all logs generated by the D-Bus executable:</para>
598 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
600 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
602 <programlisting>journalctl /dev/sda</programlisting>
607 <title>See Also</title>
609 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
610 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
611 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
612 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
613 <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>