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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>Controls the number of
163 journal lines to show, counting from
164 the most recent ones. The argument is
165 optional, and if specified is a
166 positive integer. If not specified and
167 in follow mode defaults to 10. If this
168 option is not passed and follow mode
169 is not enabled, how many lines are
171 limited.</para></listitem>
175 <term><option>--no-tail</option></term>
177 <listitem><para>Show all stored output
178 lines, even in follow mode. Undoes the
180 <option>--lines=</option>.</para></listitem>
184 <term><option>--output=</option></term>
185 <term><option>-o</option></term>
187 <listitem><para>Controls the
188 formatting of the journal entries that
189 are shown. Takes one of
190 <literal>short</literal>,
191 <literal>short-monotonic</literal>,
192 <literal>verbose</literal>,
193 <literal>export</literal>,
194 <literal>json</literal>,
195 <literal>json-pretty</literal>,
196 <literal>json-sse</literal>,
197 <literal>cat</literal>. <literal>short</literal>
198 is the default and generates an output
199 that is mostly identical to the
200 formatting of classic syslog log
201 files, showing one line per journal
202 entry. <literal>short-monotonic</literal>
203 is very similar but shows monotonic
204 timestamps instead of wallclock
205 timestamps. <literal>verbose</literal>
206 shows the full structured entry items
208 fields. <literal>export</literal>
209 serializes the journal into a binary
210 (but mostly text-based) stream
211 suitable for backups and network
213 url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal
214 Export Format</ulink> for more
215 information). <literal>json</literal>
216 formats entries as JSON data
218 line. <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>--quiet</option></term>
237 <term><option>-q</option></term>
239 <listitem><para>Suppresses any warning
240 message regarding inaccessible system
241 journals when run as normal
242 user.</para></listitem>
246 <term><option>--merge</option></term>
247 <term><option>-m</option></term>
249 <listitem><para>Show entries
250 interleaved from all available
251 journals, including remote
252 ones.</para></listitem>
256 <term><option>--this-boot</option></term>
257 <term><option>-b</option></term>
259 <listitem><para>Show data only from
260 current boot.</para></listitem>
264 <term><option>--cursor=</option></term>
265 <term><option>-c</option></term>
267 <listitem><para>Start showing entries
268 from the location in the journal
269 specified by the passed
270 cursor.</para></listitem>
274 <term><option>--since=</option></term>
275 <term><option>--until=</option></term>
277 <listitem><para>Start showing entries
278 on or newer than the specified date,
279 or on or older than the specified
280 date, respectively. Date specifications should be of
281 the format "2012-10-30 18:17:16". If
282 the time part is omitted, 00:00:00 is
283 assumed. If only the seconds component
284 is omitted, :00 is assumed. If the
285 date component is ommitted, the
286 current day is assumed. Alternatively
288 <literal>yesterday</literal>,
289 <literal>today</literal>,
290 <literal>tomorrow</literal> are
291 understood, which refer to 00:00:00 of
292 the day before the current day, the
293 current day, or the day after the
294 current day, respectively. <literal>now</literal>
295 refers to the current time. Finally,
296 relative times may be specified,
297 prefixed with <literal>-</literal> or
298 <literal>+</literal>, referring to
299 times before or after the current
300 time, respectively.</para></listitem>
304 <term><option>--directory=</option></term>
305 <term><option>-D</option></term>
307 <listitem><para>Takes an absolute
308 directory path as argument. If
309 specified journalctl will operate on the
310 specified journal directory instead of
311 the default runtime and system journal
312 paths.</para></listitem>
316 <term><option>-p</option></term>
317 <term><option>--priority=</option></term>
319 <listitem><para>Filter output by
320 message priorities or priority
321 ranges. Takes either a single numeric
322 or textual log level (i.e. between
323 0/<literal>emerg</literal> and
324 7/<literal>debug</literal>), or a
325 range of numeric/text log levels in
326 the form FROM..TO. The log levels are
327 the usual syslog log levels as
329 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
330 i.e. <literal>emerg</literal> (0),
331 <literal>alert</literal> (1),
332 <literal>crit</literal> (2),
333 <literal>err</literal> (3),
334 <literal>warning</literal> (4),
335 <literal>notice</literal> (5),
336 <literal>info</literal> (6),
337 <literal>debug</literal> (7). If a
338 single log level is specified all
339 messages with this log level or a
340 lower (hence more important) log level
341 are shown. If a range is specified all
342 messages within the range are shown,
343 including both the start and the end
344 value of the range.</para></listitem>
348 <term><option>--new-id128</option></term>
350 <listitem><para>Instead of showing
351 journal contents generate a new 128
352 bit ID suitable for identifying
353 messages. This is intended for usage
354 by developers who need a new
355 identifier for a new message they
356 introduce and want to make
357 recognizable. Will print the new ID in
358 three different formats which can be
359 copied into source code or
360 similar.</para></listitem>
364 <term><option>--header</option></term>
366 <listitem><para>Instead of showing
367 journal contents show internal header
368 information of the journal fields
369 accessed.</para></listitem>
373 <term><option>--disk-usage</option></term>
375 <listitem><para>Shows the current disk
377 journal files.</para></listitem>
381 <term><option>--setup-keys</option></term>
383 <listitem><para>Instead of showing
384 journal contents generate a new key
385 pair for Forward Secure Sealing
386 (FSS). This will generate a sealing
387 key and a verification key. The
388 sealing key is stored in the journal
389 data directory and shall remain on the
390 host. The verification key should be
391 stored externally.</para></listitem>
395 <term><option>--interval=</option></term>
397 <listitem><para>Specifies the change
398 interval for the sealing key, when
399 generating an FSS key pair with
400 <option>--setup-keys</option>. Shorter
401 intervals increase CPU consumption but
402 shorten the time range of
404 alterations. Defaults to
405 15min.</para></listitem>
409 <term><option>--verify</option></term>
411 <listitem><para>Check the journal file
412 for internal consistency. If the
413 file has been generated with FSS
414 enabled, and the FSS verification key
415 has been specified with
416 <option>--verify-key=</option>
417 authenticity of the journal file is
418 verified.</para></listitem>
422 <term><option>--verify-key=</option></term>
424 <listitem><para>Specifies the FSS
425 verification key to use for the
426 <option>--verify</option>
427 operation.</para></listitem>
434 <title>Exit status</title>
436 <para>On success 0 is returned, a non-zero failure
437 code otherwise.</para>
441 <title>Environment</title>
445 <term><varname>$SYSTEMD_PAGER</varname></term>
446 <listitem><para>Pager to use when
447 <option>--no-pager</option> is not given;
448 overrides <varname>$PAGER</varname>. Setting
449 this to an empty string or the value
450 <literal>cat</literal> is equivalent to passing
451 <option>--no-pager</option>.</para></listitem>
457 <title>Examples</title>
459 <para>Without arguments all collected logs are shown
462 <programlisting>journalctl</programlisting>
464 <para>With one match specified all entries with a field matching the expression are shown:</para>
466 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
468 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
470 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
472 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
474 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
476 <para>If the separator "<literal>+</literal>" is used
477 two expressions may be combined in a logical OR. The
478 following will show all messages from the Avahi
479 service process with the PID 28097 plus all messages
480 from the D-Bus service (from any of its
483 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
485 <para>Show all logs generated by the D-Bus executable:</para>
487 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
489 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
491 <programlisting>journalctl /dev/sda</programlisting>
496 <title>See Also</title>
498 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
499 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
500 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
501 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
502 <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>