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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
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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>-n</option></term>
167 <term><option>--lines=</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>-r</option></term>
189 <term><option>--reverse</option></term>
191 <listitem><para>Reverse output, so the newest
192 entries are displayed first.</para></listitem>
196 <term><option>-o</option></term>
197 <term><option>--output=</option></term>
199 <listitem><para>Controls the
200 formatting of the journal entries that
201 are shown. Takes one of
202 <literal>short</literal>,
203 <literal>short-monotonic</literal>,
204 <literal>verbose</literal>,
205 <literal>export</literal>,
206 <literal>json</literal>,
207 <literal>json-pretty</literal>,
208 <literal>json-sse</literal>,
209 <literal>cat</literal>. <literal>short</literal>
210 is the default and generates an output
211 that is mostly identical to the
212 formatting of classic syslog log
213 files, showing one line per journal
214 entry. <literal>short-monotonic</literal>
215 is very similar but shows monotonic
216 timestamps instead of wallclock
217 timestamps. <literal>verbose</literal>
218 shows the full structured entry items
220 fields. <literal>export</literal>
221 serializes the journal into a binary
222 (but mostly text-based) stream
223 suitable for backups and network
225 url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal
226 Export Format</ulink> for more
227 information). <literal>json</literal>
228 formats entries as JSON data
231 url="http://www.freedesktop.org/wiki/Software/systemd/json">Journal
232 JSON Format</ulink> for more
233 information). <literal>json-pretty</literal>
234 also formats entries as JSON data
235 structures, but formats them in
236 multiple lines in order to make them
238 humans. <literal>json-sse</literal>
239 also formats entries as JSON data
240 structures, but wraps them in a format
242 url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent
243 Events</ulink>. <literal>cat</literal>
244 generates a very terse output only
245 showing the actual message of each
246 journal entry with no meta data, not
247 even a timestamp.</para></listitem>
251 <term><option>-x</option></term>
252 <term><option>--catalog</option></term>
254 <listitem><para>Augment log lines with
255 explanation texts from the message
256 catalog. This will add explanatory
257 help texts to log messages in the
258 output where this is available. These
259 short help texts will explain the
260 context of an error or log event,
261 possible solutions, as well as
262 pointers to support forums, developer
263 documentation and any other relevant
264 manuals. Note that help texts are not
265 available for all messages, but only
266 for selected ones. For more
267 information on the message catalog
268 please refer to the <ulink
269 url="http://www.freedesktop.org/wiki/Software/systemd/catalog">Message
271 Documentation</ulink>.</para></listitem>
275 <term><option>-q</option></term>
276 <term><option>--quiet</option></term>
278 <listitem><para>Suppresses any warning
279 message regarding inaccessible system
280 journals when run as normal
281 user.</para></listitem>
285 <term><option>-m</option></term>
286 <term><option>--merge</option></term>
288 <listitem><para>Show entries
289 interleaved from all available
290 journals, including remote
291 ones.</para></listitem>
295 <term><option>-b</option></term>
296 <term><option>--this-boot</option></term>
298 <listitem><para>Show data only from
299 current boot. This will add a match
300 for <literal>_BOOT_ID=</literal> for
301 the current boot ID of the
302 kernel.</para></listitem>
306 <term><option>-u</option></term>
307 <term><option>--unit=</option></term>
309 <listitem><para>Show data only of the
310 specified unit. This will add a match
311 for <literal>_SYSTEMD_UNIT=</literal>
313 unit.</para></listitem>
317 <term><option>-p</option></term>
318 <term><option>--priority=</option></term>
320 <listitem><para>Filter output by
321 message priorities or priority
322 ranges. Takes either a single numeric
323 or textual log level (i.e. between
324 0/<literal>emerg</literal> and
325 7/<literal>debug</literal>), or a
326 range of numeric/text log levels in
327 the form FROM..TO. The log levels are
328 the usual syslog log levels as
330 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
331 i.e. <literal>emerg</literal> (0),
332 <literal>alert</literal> (1),
333 <literal>crit</literal> (2),
334 <literal>err</literal> (3),
335 <literal>warning</literal> (4),
336 <literal>notice</literal> (5),
337 <literal>info</literal> (6),
338 <literal>debug</literal> (7). If a
339 single log level is specified all
340 messages with this log level or a
341 lower (hence more important) log level
342 are shown. If a range is specified all
343 messages within the range are shown,
344 including both the start and the end
345 value of the range. This will add
346 <literal>PRIORITY=</literal> matches
348 priorities.</para></listitem>
352 <term><option>-c</option></term>
353 <term><option>--cursor=</option></term>
355 <listitem><para>Start showing entries
356 from the location in the journal
357 specified by the passed
358 cursor.</para></listitem>
362 <term><option>--since=</option></term>
363 <term><option>--until=</option></term>
365 <listitem><para>Start showing entries
366 on or newer than the specified date,
367 or on or older than the specified
368 date, respectively. Date specifications should be of
369 the format "2012-10-30 18:17:16". If
370 the time part is omitted, 00:00:00 is
371 assumed. If only the seconds component
372 is omitted, :00 is assumed. If the
373 date component is omitted, the
374 current day is assumed. Alternatively
376 <literal>yesterday</literal>,
377 <literal>today</literal>,
378 <literal>tomorrow</literal> are
379 understood, which refer to 00:00:00 of
380 the day before the current day, the
381 current day, or the day after the
382 current day, respectively. <literal>now</literal>
383 refers to the current time. Finally,
384 relative times may be specified,
385 prefixed with <literal>-</literal> or
386 <literal>+</literal>, referring to
387 times before or after the current
388 time, respectively.</para></listitem>
392 <term><option>-F</option></term>
393 <term><option>--field=</option></term>
395 <listitem><para>Print all possible
396 data values the specified field can
397 take in all entries of the
398 journal.</para></listitem>
402 <term><option>-D</option></term>
403 <term><option>--directory=</option></term>
405 <listitem><para>Takes an absolute
406 directory path as argument. If
407 specified journalctl will operate on the
408 specified journal directory instead of
409 the default runtime and system journal
410 paths.</para></listitem>
414 <term><option>--new-id128</option></term>
416 <listitem><para>Instead of showing
417 journal contents generate a new 128
418 bit ID suitable for identifying
419 messages. This is intended for usage
420 by developers who need a new
421 identifier for a new message they
422 introduce and want to make
423 recognizable. Will print the new ID in
424 three different formats which can be
425 copied into source code or
426 similar.</para></listitem>
430 <term><option>--header</option></term>
432 <listitem><para>Instead of showing
433 journal contents show internal header
434 information of the journal fields
435 accessed.</para></listitem>
439 <term><option>--disk-usage</option></term>
441 <listitem><para>Shows the current disk
443 journal files.</para></listitem>
447 <term><option>--list-catalog</option></term>
449 <listitem><para>List the contents of
450 the message catalog, as table of
451 message IDs plus their short
452 description strings.</para></listitem>
456 <term><option>--update-catalog</option></term>
458 <listitem><para>Update the message
459 catalog index. This command needs to
460 be executed each time new catalog
461 files are installed, removed or
462 updated to rebuild the binary catalog
463 index.</para></listitem>
467 <term><option>--setup-keys</option></term>
469 <listitem><para>Instead of showing
470 journal contents generate a new key
471 pair for Forward Secure Sealing
472 (FSS). This will generate a sealing
473 key and a verification key. The
474 sealing key is stored in the journal
475 data directory and shall remain on the
476 host. The verification key should be
477 stored externally.</para></listitem>
481 <term><option>--interval=</option></term>
483 <listitem><para>Specifies the change
484 interval for the sealing key, when
485 generating an FSS key pair with
486 <option>--setup-keys</option>. Shorter
487 intervals increase CPU consumption but
488 shorten the time range of
490 alterations. Defaults to
491 15min.</para></listitem>
495 <term><option>--verify</option></term>
497 <listitem><para>Check the journal file
498 for internal consistency. If the
499 file has been generated with FSS
500 enabled, and the FSS verification key
501 has been specified with
502 <option>--verify-key=</option>
503 authenticity of the journal file is
504 verified.</para></listitem>
508 <term><option>--verify-key=</option></term>
510 <listitem><para>Specifies the FSS
511 verification key to use for the
512 <option>--verify</option>
513 operation.</para></listitem>
520 <title>Exit status</title>
522 <para>On success 0 is returned, a non-zero failure
523 code otherwise.</para>
527 <title>Environment</title>
529 <variablelist class='environment-variables'>
531 <term><varname>$SYSTEMD_PAGER</varname></term>
532 <listitem><para>Pager to use when
533 <option>--no-pager</option> is not given;
534 overrides <varname>$PAGER</varname>. Setting
535 this to an empty string or the value
536 <literal>cat</literal> is equivalent to passing
537 <option>--no-pager</option>.</para></listitem>
543 <title>Examples</title>
545 <para>Without arguments all collected logs are shown
548 <programlisting>journalctl</programlisting>
550 <para>With one match specified all entries with a field matching the expression are shown:</para>
552 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
554 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
556 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
558 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
560 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
562 <para>If the separator "<literal>+</literal>" is used
563 two expressions may be combined in a logical OR. The
564 following will show all messages from the Avahi
565 service process with the PID 28097 plus all messages
566 from the D-Bus service (from any of its
569 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
571 <para>Show all logs generated by the D-Bus executable:</para>
573 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
575 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
577 <programlisting>journalctl /dev/sda</programlisting>
582 <title>See Also</title>
584 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
585 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
586 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
587 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
588 <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>