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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>cat</literal>. <literal>short</literal>
197 is the default and generates an output
198 that is mostly identical to the
199 formatting of classic syslog log
200 files, showing one line per journal
201 entry. <literal>short-monotonic</literal>
202 is very similar but shows monotonic
203 timestamps instead of wallclock
204 timestamps. <literal>verbose</literal>
205 shows the full structured entry items
207 fields. <literal>export</literal>
208 serializes the journal into a binary
209 (but mostly text-based) stream
210 suitable for backups and network
212 url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal
213 Export Format</ulink> for more
214 information). <literal>json</literal>
215 formats entries as JSON data
217 line. <literal>json-pretty</literal>
218 also formats entries as JSON data
219 structures, but formats them in
220 multiple lines in order to make them
222 humans. <literal>cat</literal>
223 generates a very terse output only
224 showing the actual message of each
225 journal entry with no meta data, not
226 even a timestamp.</para></listitem>
230 <term><option>--quiet</option></term>
231 <term><option>-q</option></term>
233 <listitem><para>Suppresses any warning
234 message regarding inaccessible system
235 journals when run as normal
236 user.</para></listitem>
240 <term><option>--merge</option></term>
241 <term><option>-m</option></term>
243 <listitem><para>Show entries
244 interleaved from all available
245 journals, including remote
246 ones.</para></listitem>
250 <term><option>--this-boot</option></term>
251 <term><option>-b</option></term>
253 <listitem><para>Show data only from
254 current boot.</para></listitem>
258 <term><option>--cursor=</option></term>
259 <term><option>-c</option></term>
261 <listitem><para>Jump to the location
262 in the journal specified by the passed
263 cursor.</para></listitem>
267 <term><option>--directory=</option></term>
268 <term><option>-D</option></term>
270 <listitem><para>Takes an absolute
271 directory path as argument. If
272 specified journalctl will operate on the
273 specified journal directory instead of
274 the default runtime and system journal
275 paths.</para></listitem>
279 <term><option>-p</option></term>
280 <term><option>--priority=</option></term>
282 <listitem><para>Filter output by
283 message priorities or priority
284 ranges. Takes either a single numeric
285 or textual log level (i.e. between
286 0/<literal>emerg</literal> and
287 7/<literal>debug</literal>), or a
288 range of numeric/text log levels in
289 the form FROM..TO. The log levels are
290 the usual syslog log levels as
292 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
293 i.e. <literal>emerg</literal> (0),
294 <literal>alert</literal> (1),
295 <literal>crit</literal> (2),
296 <literal>err</literal> (3),
297 <literal>warning</literal> (4),
298 <literal>notice</literal> (5),
299 <literal>info</literal> (6),
300 <literal>debug</literal> (7). If a
301 single log level is specified all
302 messages with this log level or a
303 lower (hence more important) log level
304 are shown. If a range is specified all
305 messages within the range are shown,
306 including both the start and the end
307 value of the range.</para></listitem>
311 <term><option>--new-id128</option></term>
313 <listitem><para>Instead of showing
314 journal contents generate a new 128
315 bit ID suitable for identifying
316 messages. This is intended for usage
317 by developers who need a new
318 identifier for a new message they
319 introduce and want to make
320 recognizable. Will print the new ID in
321 three different formats which can be
322 copied into source code or
323 similar.</para></listitem>
327 <term><option>--header</option></term>
329 <listitem><para>Instead of showing
330 journal contents show internal header
331 information of the journal fields
332 accessed.</para></listitem>
336 <term><option>--disk-usage</option></term>
338 <listitem><para>Shows the current disk
340 journal files.</para></listitem>
344 <term><option>--setup-keys</option></term>
346 <listitem><para>Instead of showing
347 journal contents generate a new key
348 pair for Forward Secure Sealing
349 (FSS). This will generate a sealing
350 key and a verification key. The
351 sealing key is stored in the journal
352 data directory and shall remain on the
353 host. The verification key should be
354 stored externally.</para></listitem>
358 <term><option>--interval=</option></term>
360 <listitem><para>Specifies the change
361 interval for the sealing key, when
362 generating an FSS key pair with
363 <option>--setup-keys</option>. Shorter
364 intervals increase CPU consumption but
365 shorten the time range of
367 alterations. Defaults to
368 15min.</para></listitem>
372 <term><option>--verify</option></term>
374 <listitem><para>Check the journal file
375 for internal consistency. If the
376 file has been generated with FSS
377 enabled, and the FSS verification key
378 has been specified with
379 <option>--verify-key=</option>
380 authenticity of the journal file is
381 verified.</para></listitem>
385 <term><option>--verify-key=</option></term>
387 <listitem><para>Specifies the FSS
388 verification key to use for the
389 <option>--verify</option>
390 operation.</para></listitem>
397 <title>Exit status</title>
399 <para>On success 0 is returned, a non-zero failure
400 code otherwise.</para>
404 <title>Environment</title>
408 <term><varname>$SYSTEMD_PAGER</varname></term>
409 <listitem><para>Pager to use when
410 <option>--no-pager</option> is not given;
411 overrides <varname>$PAGER</varname>. Setting
412 this to an empty string or the value
413 <literal>cat</literal> is equivalent to passing
414 <option>--no-pager</option>.</para></listitem>
420 <title>Examples</title>
422 <para>Without arguments all collected logs are shown
425 <programlisting>journalctl</programlisting>
427 <para>With one match specified all entries with a field matching the expression are shown:</para>
429 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
431 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
433 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
435 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
437 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
439 <para>If the separator "<literal>+</literal>" is used
440 two expressions may be combined in a logical OR. The
441 following will show all messages from the Avahi
442 service process with the PID 28097 plus all messages
443 from the D-Bus service (from any of its
446 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
448 <para>Show all logs generated by the D-Bus executable:</para>
450 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
452 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
454 <programlisting>journalctl /dev/sda</programlisting>
459 <title>See Also</title>
461 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
462 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
463 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
464 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
465 <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>