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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>--all</option></term>
140 <term><option>-a</option></term>
142 <listitem><para>Show all fields in
143 full, even if they include unprintable
144 characters or are very
145 long.</para></listitem>
149 <term><option>--follow</option></term>
150 <term><option>-f</option></term>
152 <listitem><para>Show only the most recent
153 journal entries, and continuously print
154 new entries as they are appended to
155 the journal.</para></listitem>
159 <term><option>--lines=</option></term>
160 <term><option>-n</option></term>
162 <listitem><para>Show the most recent
163 journal events and limit the number of
165 <option>--follow</option> is used,
166 this option is implied. The argument,
167 a positive integer, is optional, and
168 defaults to 10. </para></listitem>
172 <term><option>--no-tail</option></term>
174 <listitem><para>Show all stored output
175 lines, even in follow mode. Undoes the
177 <option>--lines=</option>.</para></listitem>
181 <term><option>--output=</option></term>
182 <term><option>-o</option></term>
184 <listitem><para>Controls the
185 formatting of the journal entries that
186 are shown. Takes one of
187 <literal>short</literal>,
188 <literal>short-monotonic</literal>,
189 <literal>verbose</literal>,
190 <literal>export</literal>,
191 <literal>json</literal>,
192 <literal>json-pretty</literal>,
193 <literal>json-sse</literal>,
194 <literal>cat</literal>. <literal>short</literal>
195 is the default and generates an output
196 that is mostly identical to the
197 formatting of classic syslog log
198 files, showing one line per journal
199 entry. <literal>short-monotonic</literal>
200 is very similar but shows monotonic
201 timestamps instead of wallclock
202 timestamps. <literal>verbose</literal>
203 shows the full structured entry items
205 fields. <literal>export</literal>
206 serializes the journal into a binary
207 (but mostly text-based) stream
208 suitable for backups and network
210 url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal
211 Export Format</ulink> for more
212 information). <literal>json</literal>
213 formats entries as JSON data
216 url="http://www.freedesktop.org/wiki/Software/systemd/json">Journal
217 JSON Format</ulink> for more
218 information). <literal>json-pretty</literal>
219 also formats entries as JSON data
220 structures, but formats them in
221 multiple lines in order to make them
223 humans. <literal>json-sse</literal>
224 also formats entries as JSON data
225 structures, but wraps them in a format
227 url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent
228 Events</ulink>. <literal>cat</literal>
229 generates a very terse output only
230 showing the actual message of each
231 journal entry with no meta data, not
232 even a timestamp.</para></listitem>
236 <term><option>--catalog</option></term>
237 <term><option>-x</option></term>
239 <listitem><para>Augment log lines with
240 explanation texts from the message
241 catalog. This will add explanatory
242 help texts to log messages in the
243 output where this is available. These
244 short help texts will explain the
245 context of an error or log event,
246 possible solutions, as well as
247 pointers to support forums, developer
248 documentation and any other relevant
249 manuals. Note that help texts are not
250 available for all messages, but only
251 for selected ones. For more
252 information on the message catalog
253 please refer to the <ulink
254 url="http://www.freedesktop.org/wiki/Software/systemd/catalog">Message
256 Documentation</ulink>.</para></listitem>
260 <term><option>--quiet</option></term>
261 <term><option>-q</option></term>
263 <listitem><para>Suppresses any warning
264 message regarding inaccessible system
265 journals when run as normal
266 user.</para></listitem>
270 <term><option>--merge</option></term>
271 <term><option>-m</option></term>
273 <listitem><para>Show entries
274 interleaved from all available
275 journals, including remote
276 ones.</para></listitem>
280 <term><option>--this-boot</option></term>
281 <term><option>-b</option></term>
283 <listitem><para>Show data only from
284 current boot. This will add a match
285 for <literal>_BOOT_ID=</literal> for
286 the current boot ID of the
287 kernel.</para></listitem>
291 <term><option>--unit=</option></term>
292 <term><option>-u</option></term>
294 <listitem><para>Show data only of the
295 specified unit. This will add a match
296 for <literal>_SYSTEMD_UNIT=</literal>
298 unit.</para></listitem>
302 <term><option>-p</option></term>
303 <term><option>--priority=</option></term>
305 <listitem><para>Filter output by
306 message priorities or priority
307 ranges. Takes either a single numeric
308 or textual log level (i.e. between
309 0/<literal>emerg</literal> and
310 7/<literal>debug</literal>), or a
311 range of numeric/text log levels in
312 the form FROM..TO. The log levels are
313 the usual syslog log levels as
315 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
316 i.e. <literal>emerg</literal> (0),
317 <literal>alert</literal> (1),
318 <literal>crit</literal> (2),
319 <literal>err</literal> (3),
320 <literal>warning</literal> (4),
321 <literal>notice</literal> (5),
322 <literal>info</literal> (6),
323 <literal>debug</literal> (7). If a
324 single log level is specified all
325 messages with this log level or a
326 lower (hence more important) log level
327 are shown. If a range is specified all
328 messages within the range are shown,
329 including both the start and the end
330 value of the range. This will add
331 <literal>PRIORITY=</literal> matches
333 priorities.</para></listitem>
337 <term><option>--cursor=</option></term>
338 <term><option>-c</option></term>
340 <listitem><para>Start showing entries
341 from the location in the journal
342 specified by the passed
343 cursor.</para></listitem>
347 <term><option>--since=</option></term>
348 <term><option>--until=</option></term>
350 <listitem><para>Start showing entries
351 on or newer than the specified date,
352 or on or older than the specified
353 date, respectively. Date specifications should be of
354 the format "2012-10-30 18:17:16". If
355 the time part is omitted, 00:00:00 is
356 assumed. If only the seconds component
357 is omitted, :00 is assumed. If the
358 date component is ommitted, the
359 current day is assumed. Alternatively
361 <literal>yesterday</literal>,
362 <literal>today</literal>,
363 <literal>tomorrow</literal> are
364 understood, which refer to 00:00:00 of
365 the day before the current day, the
366 current day, or the day after the
367 current day, respectively. <literal>now</literal>
368 refers to the current time. Finally,
369 relative times may be specified,
370 prefixed with <literal>-</literal> or
371 <literal>+</literal>, referring to
372 times before or after the current
373 time, respectively.</para></listitem>
377 <term><option>--field=</option></term>
378 <term><option>-F</option></term>
380 <listitem><para>Print all possible
381 data values the specified field can
382 take in all entries of the
383 journal.</para></listitem>
387 <term><option>--directory=</option></term>
388 <term><option>-D</option></term>
390 <listitem><para>Takes an absolute
391 directory path as argument. If
392 specified journalctl will operate on the
393 specified journal directory instead of
394 the default runtime and system journal
395 paths.</para></listitem>
399 <term><option>--new-id128</option></term>
401 <listitem><para>Instead of showing
402 journal contents generate a new 128
403 bit ID suitable for identifying
404 messages. This is intended for usage
405 by developers who need a new
406 identifier for a new message they
407 introduce and want to make
408 recognizable. Will print the new ID in
409 three different formats which can be
410 copied into source code or
411 similar.</para></listitem>
415 <term><option>--header</option></term>
417 <listitem><para>Instead of showing
418 journal contents show internal header
419 information of the journal fields
420 accessed.</para></listitem>
424 <term><option>--disk-usage</option></term>
426 <listitem><para>Shows the current disk
428 journal files.</para></listitem>
432 <term><option>--list-catalog</option></term>
434 <listitem><para>List the contents of
435 the message catalog, as table of
436 message IDs plus their short
437 description strings.</para></listitem>
441 <term><option>--update-catalog</option></term>
443 <listitem><para>Update the message
444 catalog index. This command needs to
445 be executed each time new catalog
446 files are installed, removed or
447 updated to rebuild the binary catalog
448 index.</para></listitem>
452 <term><option>--setup-keys</option></term>
454 <listitem><para>Instead of showing
455 journal contents generate a new key
456 pair for Forward Secure Sealing
457 (FSS). This will generate a sealing
458 key and a verification key. The
459 sealing key is stored in the journal
460 data directory and shall remain on the
461 host. The verification key should be
462 stored externally.</para></listitem>
466 <term><option>--interval=</option></term>
468 <listitem><para>Specifies the change
469 interval for the sealing key, when
470 generating an FSS key pair with
471 <option>--setup-keys</option>. Shorter
472 intervals increase CPU consumption but
473 shorten the time range of
475 alterations. Defaults to
476 15min.</para></listitem>
480 <term><option>--verify</option></term>
482 <listitem><para>Check the journal file
483 for internal consistency. If the
484 file has been generated with FSS
485 enabled, and the FSS verification key
486 has been specified with
487 <option>--verify-key=</option>
488 authenticity of the journal file is
489 verified.</para></listitem>
493 <term><option>--verify-key=</option></term>
495 <listitem><para>Specifies the FSS
496 verification key to use for the
497 <option>--verify</option>
498 operation.</para></listitem>
505 <title>Exit status</title>
507 <para>On success 0 is returned, a non-zero failure
508 code otherwise.</para>
512 <title>Environment</title>
516 <term><varname>$SYSTEMD_PAGER</varname></term>
517 <listitem><para>Pager to use when
518 <option>--no-pager</option> is not given;
519 overrides <varname>$PAGER</varname>. Setting
520 this to an empty string or the value
521 <literal>cat</literal> is equivalent to passing
522 <option>--no-pager</option>.</para></listitem>
528 <title>Examples</title>
530 <para>Without arguments all collected logs are shown
533 <programlisting>journalctl</programlisting>
535 <para>With one match specified all entries with a field matching the expression are shown:</para>
537 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
539 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
541 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
543 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
545 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
547 <para>If the separator "<literal>+</literal>" is used
548 two expressions may be combined in a logical OR. The
549 following will show all messages from the Avahi
550 service process with the PID 28097 plus all messages
551 from the D-Bus service (from any of its
554 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
556 <para>Show all logs generated by the D-Bus executable:</para>
558 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
560 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
562 <programlisting>journalctl /dev/sda</programlisting>
567 <title>See Also</title>
569 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
570 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
571 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
572 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
573 <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>