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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>--directory=</option></term>
259 <term><option>-D</option></term>
261 <listitem><para>Takes an absolute
262 directory path as argument. If
263 specified journalctl will operate on the
264 specified journal directory instead of
265 the default runtime and system journal
266 paths.</para></listitem>
270 <term><option>-p</option></term>
271 <term><option>--priority=</option></term>
273 <listitem><para>Filter output by
274 message priorities or priority
275 ranges. Takes either a single numeric
276 or textual log level (i.e. between
277 0/<literal>emerg</literal> and
278 7/<literal>debug</literal>), or a
279 range of numeric/text log levels in
280 the form FROM..TO. The log levels are
281 the usual syslog log levels as
283 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
284 i.e. <literal>emerg</literal> (0),
285 <literal>alert</literal> (1),
286 <literal>crit</literal> (2),
287 <literal>err</literal> (3),
288 <literal>warning</literal> (4),
289 <literal>notice</literal> (5),
290 <literal>info</literal> (6),
291 <literal>debug</literal> (7). If a
292 single log level is specified all
293 messages with this log level or a
294 lower (hence more important) log level
295 are shown. If a range is specified all
296 messages within the range are shown,
297 including both the start and the end
298 value of the range.</para></listitem>
302 <term><option>--new-id128</option></term>
304 <listitem><para>Instead of showing
305 journal contents generate a new 128
306 bit ID suitable for identifying
307 messages. This is intended for usage
308 by developers who need a new
309 identifier for a new message they
310 introduce and want to make
311 recognizable. Will print the new ID in
312 three different formats which can be
313 copied into source code or
314 similar.</para></listitem>
318 <term><option>--header</option></term>
320 <listitem><para>Instead of showing
321 journal contents show internal header
322 information of the journal fields
323 accessed.</para></listitem>
327 <term><option>--disk-usage</option></term>
329 <listitem><para>Shows the current disk
331 journal files.</para></listitem>
335 <term><option>--setup-keys</option></term>
337 <listitem><para>Instead of showing
338 journal contents generate a new key
339 pair for Forward Secure Sealing
340 (FSS). This will generate a sealing
341 key and a verification key. The
342 sealing key is stored in the journal
343 data directory and shall remain on the
344 host. The verification key should be
345 stored externally.</para></listitem>
349 <term><option>--interval=</option></term>
351 <listitem><para>Specifies the change
352 interval for the sealing key, when
353 generating an FSS key pair with
354 <option>--setup-keys</option>. Shorter
355 intervals increase CPU consumption but
356 shorten the time range of
358 alterations. Defaults to
359 15min.</para></listitem>
363 <term><option>--verify</option></term>
365 <listitem><para>Check the journal file
366 for internal consistency. If the
367 file has been generated with FSS
368 enabled, and the FSS verification key
369 has been specified with
370 <option>--verify-key=</option>
371 authenticity of the journal file is
372 verified.</para></listitem>
376 <term><option>--verify-key=</option></term>
378 <listitem><para>Specifies the FSS
379 verification key to use for the
380 <option>--verify</option>
381 operation.</para></listitem>
388 <title>Exit status</title>
390 <para>On success 0 is returned, a non-zero failure
391 code otherwise.</para>
395 <title>Environment</title>
399 <term><varname>$SYSTEMD_PAGER</varname></term>
400 <listitem><para>Pager to use when
401 <option>--no-pager</option> is not given;
402 overrides <varname>$PAGER</varname>. Setting
403 this to an empty string or the value
404 <literal>cat</literal> is equivalent to passing
405 <option>--no-pager</option>.</para></listitem>
411 <title>Examples</title>
413 <para>Without arguments all collected logs are shown
416 <programlisting>journalctl</programlisting>
418 <para>With one match specified all entries with a field matching the expression are shown:</para>
420 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
422 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
424 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
426 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
428 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
430 <para>If the separator "<literal>+</literal>" is used
431 two expressions may be combined in a logical OR. The
432 following will show all messages from the Avahi
433 service process with the PID 28097 plus all messages
434 from the D-Bus service (from any of its
437 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
439 <para>Show all logs generated by the D-Bus executable:</para>
441 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
443 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
445 <programlisting>journalctl /dev/sda</programlisting>
450 <title>See Also</title>
452 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
453 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
454 <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
455 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
456 <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>