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6 This file is part of systemd.
8 Copyright 2012 Lennart Poettering
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24 <refentry id="journalctl">
27 <title>journalctl</title>
28 <productname>systemd</productname>
32 <contrib>Developer</contrib>
33 <firstname>Lennart</firstname>
34 <surname>Poettering</surname>
35 <email>lennart@poettering.net</email>
41 <refentrytitle>journalctl</refentrytitle>
42 <manvolnum>1</manvolnum>
46 <refname>journalctl</refname>
47 <refpurpose>Query the systemd journal</refpurpose>
52 <command>journalctl <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>--help</option></term>
118 <term><option>-h</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>--all</option></term>
147 <term><option>-a</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>--follow</option></term>
157 <term><option>-f</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>--lines=</option></term>
167 <term><option>-n</option></term>
169 <listitem><para>Show the most recent
170 journal events and limit the number of
172 <option>--follow</option> is used,
173 this option is implied. The argument,
174 a positive integer, is optional, and
175 defaults to 10. </para></listitem>
179 <term><option>--no-tail</option></term>
181 <listitem><para>Show all stored output
182 lines, even in follow mode. Undoes the
184 <option>--lines=</option>.</para></listitem>
188 <term><option>--output=</option></term>
189 <term><option>-o</option></term>
191 <listitem><para>Controls the
192 formatting of the journal entries that
193 are shown. Takes one of
194 <literal>short</literal>,
195 <literal>short-monotonic</literal>,
196 <literal>verbose</literal>,
197 <literal>export</literal>,
198 <literal>json</literal>,
199 <literal>json-pretty</literal>,
200 <literal>json-sse</literal>,
201 <literal>cat</literal>. <literal>short</literal>
202 is the default and generates an output
203 that is mostly identical to the
204 formatting of classic syslog log
205 files, showing one line per journal
206 entry. <literal>short-monotonic</literal>
207 is very similar but shows monotonic
208 timestamps instead of wallclock
209 timestamps. <literal>verbose</literal>
210 shows the full structured entry items
212 fields. <literal>export</literal>
213 serializes the journal into a binary
214 (but mostly text-based) stream
215 suitable for backups and network
217 url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal
218 Export Format</ulink> for more
219 information). <literal>json</literal>
220 formats entries as JSON data
223 url="http://www.freedesktop.org/wiki/Software/systemd/json">Journal
224 JSON Format</ulink> for more
225 information). <literal>json-pretty</literal>
226 also formats entries as JSON data
227 structures, but formats them in
228 multiple lines in order to make them
230 humans. <literal>json-sse</literal>
231 also formats entries as JSON data
232 structures, but wraps them in a format
234 url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent
235 Events</ulink>. <literal>cat</literal>
236 generates a very terse output only
237 showing the actual message of each
238 journal entry with no meta data, not
239 even a timestamp.</para></listitem>
243 <term><option>--catalog</option></term>
244 <term><option>-x</option></term>
246 <listitem><para>Augment log lines with
247 explanation texts from the message
248 catalog. This will add explanatory
249 help texts to log messages in the
250 output where this is available. These
251 short help texts will explain the
252 context of an error or log event,
253 possible solutions, as well as
254 pointers to support forums, developer
255 documentation and any other relevant
256 manuals. Note that help texts are not
257 available for all messages, but only
258 for selected ones. For more
259 information on the message catalog
260 please refer to the <ulink
261 url="http://www.freedesktop.org/wiki/Software/systemd/catalog">Message
263 Documentation</ulink>.</para></listitem>
267 <term><option>--quiet</option></term>
268 <term><option>-q</option></term>
270 <listitem><para>Suppresses any warning
271 message regarding inaccessible system
272 journals when run as normal
273 user.</para></listitem>
277 <term><option>--merge</option></term>
278 <term><option>-m</option></term>
280 <listitem><para>Show entries
281 interleaved from all available
282 journals, including remote
283 ones.</para></listitem>
287 <term><option>--this-boot</option></term>
288 <term><option>-b</option></term>
290 <listitem><para>Show data only from
291 current boot. This will add a match
292 for <literal>_BOOT_ID=</literal> for
293 the current boot ID of the
294 kernel.</para></listitem>
298 <term><option>--unit=</option></term>
299 <term><option>-u</option></term>
301 <listitem><para>Show data only of the
302 specified unit. This will add a match
303 for <literal>_SYSTEMD_UNIT=</literal>
305 unit.</para></listitem>
309 <term><option>-p</option></term>
310 <term><option>--priority=</option></term>
312 <listitem><para>Filter output by
313 message priorities or priority
314 ranges. Takes either a single numeric
315 or textual log level (i.e. between
316 0/<literal>emerg</literal> and
317 7/<literal>debug</literal>), or a
318 range of numeric/text log levels in
319 the form FROM..TO. The log levels are
320 the usual syslog log levels as
322 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
323 i.e. <literal>emerg</literal> (0),
324 <literal>alert</literal> (1),
325 <literal>crit</literal> (2),
326 <literal>err</literal> (3),
327 <literal>warning</literal> (4),
328 <literal>notice</literal> (5),
329 <literal>info</literal> (6),
330 <literal>debug</literal> (7). If a
331 single log level is specified all
332 messages with this log level or a
333 lower (hence more important) log level
334 are shown. If a range is specified all
335 messages within the range are shown,
336 including both the start and the end
337 value of the range. This will add
338 <literal>PRIORITY=</literal> matches
340 priorities.</para></listitem>
344 <term><option>--cursor=</option></term>
345 <term><option>-c</option></term>
347 <listitem><para>Start showing entries
348 from the location in the journal
349 specified by the passed
350 cursor.</para></listitem>
354 <term><option>--since=</option></term>
355 <term><option>--until=</option></term>
357 <listitem><para>Start showing entries
358 on or newer than the specified date,
359 or on or older than the specified
360 date, respectively. Date specifications should be of
361 the format "2012-10-30 18:17:16". If
362 the time part is omitted, 00:00:00 is
363 assumed. If only the seconds component
364 is omitted, :00 is assumed. If the
365 date component is omitted, the
366 current day is assumed. Alternatively
368 <literal>yesterday</literal>,
369 <literal>today</literal>,
370 <literal>tomorrow</literal> are
371 understood, which refer to 00:00:00 of
372 the day before the current day, the
373 current day, or the day after the
374 current day, respectively. <literal>now</literal>
375 refers to the current time. Finally,
376 relative times may be specified,
377 prefixed with <literal>-</literal> or
378 <literal>+</literal>, referring to
379 times before or after the current
380 time, respectively.</para></listitem>
384 <term><option>--field=</option></term>
385 <term><option>-F</option></term>
387 <listitem><para>Print all possible
388 data values the specified field can
389 take in all entries of the
390 journal.</para></listitem>
394 <term><option>--directory=</option></term>
395 <term><option>-D</option></term>
397 <listitem><para>Takes an absolute
398 directory path as argument. If
399 specified journalctl will operate on the
400 specified journal directory instead of
401 the default runtime and system journal
402 paths.</para></listitem>
406 <term><option>--new-id128</option></term>
408 <listitem><para>Instead of showing
409 journal contents generate a new 128
410 bit ID suitable for identifying
411 messages. This is intended for usage
412 by developers who need a new
413 identifier for a new message they
414 introduce and want to make
415 recognizable. Will print the new ID in
416 three different formats which can be
417 copied into source code or
418 similar.</para></listitem>
422 <term><option>--header</option></term>
424 <listitem><para>Instead of showing
425 journal contents show internal header
426 information of the journal fields
427 accessed.</para></listitem>
431 <term><option>--disk-usage</option></term>
433 <listitem><para>Shows the current disk
435 journal files.</para></listitem>
439 <term><option>--list-catalog</option></term>
441 <listitem><para>List the contents of
442 the message catalog, as table of
443 message IDs plus their short
444 description strings.</para></listitem>
448 <term><option>--update-catalog</option></term>
450 <listitem><para>Update the message
451 catalog index. This command needs to
452 be executed each time new catalog
453 files are installed, removed or
454 updated to rebuild the binary catalog
455 index.</para></listitem>
459 <term><option>--setup-keys</option></term>
461 <listitem><para>Instead of showing
462 journal contents generate a new key
463 pair for Forward Secure Sealing
464 (FSS). This will generate a sealing
465 key and a verification key. The
466 sealing key is stored in the journal
467 data directory and shall remain on the
468 host. The verification key should be
469 stored externally.</para></listitem>
473 <term><option>--interval=</option></term>
475 <listitem><para>Specifies the change
476 interval for the sealing key, when
477 generating an FSS key pair with
478 <option>--setup-keys</option>. Shorter
479 intervals increase CPU consumption but
480 shorten the time range of
482 alterations. Defaults to
483 15min.</para></listitem>
487 <term><option>--verify</option></term>
489 <listitem><para>Check the journal file
490 for internal consistency. If the
491 file has been generated with FSS
492 enabled, and the FSS verification key
493 has been specified with
494 <option>--verify-key=</option>
495 authenticity of the journal file is
496 verified.</para></listitem>
500 <term><option>--verify-key=</option></term>
502 <listitem><para>Specifies the FSS
503 verification key to use for the
504 <option>--verify</option>
505 operation.</para></listitem>
512 <title>Exit status</title>
514 <para>On success 0 is returned, a non-zero failure
515 code otherwise.</para>
519 <title>Environment</title>
521 <variablelist class='environment-variables'>
523 <term><varname>$SYSTEMD_PAGER</varname></term>
524 <listitem><para>Pager to use when
525 <option>--no-pager</option> is not given;
526 overrides <varname>$PAGER</varname>. Setting
527 this to an empty string or the value
528 <literal>cat</literal> is equivalent to passing
529 <option>--no-pager</option>.</para></listitem>
535 <title>Examples</title>
537 <para>Without arguments all collected logs are shown
540 <programlisting>journalctl</programlisting>
542 <para>With one match specified all entries with a field matching the expression are shown:</para>
544 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
546 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
548 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
550 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
552 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
554 <para>If the separator "<literal>+</literal>" is used
555 two expressions may be combined in a logical OR. The
556 following will show all messages from the Avahi
557 service process with the PID 28097 plus all messages
558 from the D-Bus service (from any of its
561 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
563 <para>Show all logs generated by the D-Bus executable:</para>
565 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
567 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
569 <programlisting>journalctl /dev/sda</programlisting>
574 <title>See Also</title>
576 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
577 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
578 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
579 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
580 <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>