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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
215 line. <literal>json-pretty</literal>
216 also formats entries as JSON data
217 structures, but formats them in
218 multiple lines in order to make them
220 humans. <literal>json-sse</literal>
221 also formats entries as JSON data
222 structures, but wraps them in a format
224 url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent
225 Events</ulink>. <literal>cat</literal>
226 generates a very terse output only
227 showing the actual message of each
228 journal entry with no meta data, not
229 even a timestamp.</para></listitem>
233 <term><option>--quiet</option></term>
234 <term><option>-q</option></term>
236 <listitem><para>Suppresses any warning
237 message regarding inaccessible system
238 journals when run as normal
239 user.</para></listitem>
243 <term><option>--merge</option></term>
244 <term><option>-m</option></term>
246 <listitem><para>Show entries
247 interleaved from all available
248 journals, including remote
249 ones.</para></listitem>
253 <term><option>--this-boot</option></term>
254 <term><option>-b</option></term>
256 <listitem><para>Show data only from
257 current boot. This will add a match
258 for <literal>_BOOT_ID=</literal> for
259 the current boot ID of the
260 kernel.</para></listitem>
264 <term><option>--unit=</option></term>
265 <term><option>-u</option></term>
267 <listitem><para>Show data only of the
268 specified unit. This will add a match
269 for <literal>_SYSTEMD_UNIT=</literal>
271 unit.</para></listitem>
275 <term><option>-p</option></term>
276 <term><option>--priority=</option></term>
278 <listitem><para>Filter output by
279 message priorities or priority
280 ranges. Takes either a single numeric
281 or textual log level (i.e. between
282 0/<literal>emerg</literal> and
283 7/<literal>debug</literal>), or a
284 range of numeric/text log levels in
285 the form FROM..TO. The log levels are
286 the usual syslog log levels as
288 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
289 i.e. <literal>emerg</literal> (0),
290 <literal>alert</literal> (1),
291 <literal>crit</literal> (2),
292 <literal>err</literal> (3),
293 <literal>warning</literal> (4),
294 <literal>notice</literal> (5),
295 <literal>info</literal> (6),
296 <literal>debug</literal> (7). If a
297 single log level is specified all
298 messages with this log level or a
299 lower (hence more important) log level
300 are shown. If a range is specified all
301 messages within the range are shown,
302 including both the start and the end
303 value of the range. This will add
304 <literal>PRIORITY=</literal> matches
306 priorities.</para></listitem>
310 <term><option>--cursor=</option></term>
311 <term><option>-c</option></term>
313 <listitem><para>Start showing entries
314 from the location in the journal
315 specified by the passed
316 cursor.</para></listitem>
320 <term><option>--since=</option></term>
321 <term><option>--until=</option></term>
323 <listitem><para>Start showing entries
324 on or newer than the specified date,
325 or on or older than the specified
326 date, respectively. Date specifications should be of
327 the format "2012-10-30 18:17:16". If
328 the time part is omitted, 00:00:00 is
329 assumed. If only the seconds component
330 is omitted, :00 is assumed. If the
331 date component is ommitted, the
332 current day is assumed. Alternatively
334 <literal>yesterday</literal>,
335 <literal>today</literal>,
336 <literal>tomorrow</literal> are
337 understood, which refer to 00:00:00 of
338 the day before the current day, the
339 current day, or the day after the
340 current day, respectively. <literal>now</literal>
341 refers to the current time. Finally,
342 relative times may be specified,
343 prefixed with <literal>-</literal> or
344 <literal>+</literal>, referring to
345 times before or after the current
346 time, respectively.</para></listitem>
350 <term><option>--field=</option></term>
351 <term><option>-F</option></term>
353 <listitem><para>Print all possible
354 data values the specified field can
355 take in all entries of the
356 journal.</para></listitem>
360 <term><option>--directory=</option></term>
361 <term><option>-D</option></term>
363 <listitem><para>Takes an absolute
364 directory path as argument. If
365 specified journalctl will operate on the
366 specified journal directory instead of
367 the default runtime and system journal
368 paths.</para></listitem>
372 <term><option>--new-id128</option></term>
374 <listitem><para>Instead of showing
375 journal contents generate a new 128
376 bit ID suitable for identifying
377 messages. This is intended for usage
378 by developers who need a new
379 identifier for a new message they
380 introduce and want to make
381 recognizable. Will print the new ID in
382 three different formats which can be
383 copied into source code or
384 similar.</para></listitem>
388 <term><option>--header</option></term>
390 <listitem><para>Instead of showing
391 journal contents show internal header
392 information of the journal fields
393 accessed.</para></listitem>
397 <term><option>--disk-usage</option></term>
399 <listitem><para>Shows the current disk
401 journal files.</para></listitem>
405 <term><option>--setup-keys</option></term>
407 <listitem><para>Instead of showing
408 journal contents generate a new key
409 pair for Forward Secure Sealing
410 (FSS). This will generate a sealing
411 key and a verification key. The
412 sealing key is stored in the journal
413 data directory and shall remain on the
414 host. The verification key should be
415 stored externally.</para></listitem>
419 <term><option>--interval=</option></term>
421 <listitem><para>Specifies the change
422 interval for the sealing key, when
423 generating an FSS key pair with
424 <option>--setup-keys</option>. Shorter
425 intervals increase CPU consumption but
426 shorten the time range of
428 alterations. Defaults to
429 15min.</para></listitem>
433 <term><option>--verify</option></term>
435 <listitem><para>Check the journal file
436 for internal consistency. If the
437 file has been generated with FSS
438 enabled, and the FSS verification key
439 has been specified with
440 <option>--verify-key=</option>
441 authenticity of the journal file is
442 verified.</para></listitem>
446 <term><option>--verify-key=</option></term>
448 <listitem><para>Specifies the FSS
449 verification key to use for the
450 <option>--verify</option>
451 operation.</para></listitem>
458 <title>Exit status</title>
460 <para>On success 0 is returned, a non-zero failure
461 code otherwise.</para>
465 <title>Environment</title>
469 <term><varname>$SYSTEMD_PAGER</varname></term>
470 <listitem><para>Pager to use when
471 <option>--no-pager</option> is not given;
472 overrides <varname>$PAGER</varname>. Setting
473 this to an empty string or the value
474 <literal>cat</literal> is equivalent to passing
475 <option>--no-pager</option>.</para></listitem>
481 <title>Examples</title>
483 <para>Without arguments all collected logs are shown
486 <programlisting>journalctl</programlisting>
488 <para>With one match specified all entries with a field matching the expression are shown:</para>
490 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
492 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
494 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
496 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
498 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
500 <para>If the separator "<literal>+</literal>" is used
501 two expressions may be combined in a logical OR. The
502 following will show all messages from the Avahi
503 service process with the PID 28097 plus all messages
504 from the D-Bus service (from any of its
507 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
509 <para>Show all logs generated by the D-Bus executable:</para>
511 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
513 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
515 <programlisting>journalctl /dev/sda</programlisting>
520 <title>See Also</title>
522 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
523 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
524 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
525 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
526 <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>