man/journalctl.xml

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  23
  24   <refentry id="journalctl"
  25             xmlns:xi="http://www.w3.org/2001/XInclude">
  26
  27     <refentryinfo>
  28       <title>journalctl</title>
  29       <productname>systemd</productname>
  30
  31       <authorgroup>
  32         <author>
  33           <contrib>Developer</contrib>
  34           <firstname>Lennart</firstname>
  35           <surname>Poettering</surname>
  36           <email>lennart@poettering.net</email>
  37         </author>
  38       </authorgroup>
  39     </refentryinfo>
  40
  41     <refmeta>
  42       <refentrytitle>journalctl</refentrytitle>
  43       <manvolnum>1</manvolnum>
  44     </refmeta>
  45
  46     <refnamediv>
  47       <refname>journalctl</refname>
  48       <refpurpose>Query the systemd journal</refpurpose>
  49     </refnamediv>
  50
  51     <refsynopsisdiv>
  52       <cmdsynopsis>
  53         <command>journalctl</command>
  54         <arg choice="opt" rep="repeat">OPTIONS</arg>
  55         <arg choice="opt" rep="repeat">MATCHES</arg>
  56       </cmdsynopsis>
  57     </refsynopsisdiv>
  58
  59     <refsect1>
  60       <title>Description</title>
  61
  62       <para><command>journalctl</command> may be used to query the
  63       contents of the
  64       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  65       journal as written by
  66       <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
  67
  68       <para>If called without parameters, it will show the full
  69       contents of the journal, starting with the oldest entry
  70       collected.</para>
  71
  72       <para>If one or more match arguments are passed, the output is
  73       filtered accordingly. A match is in the format
  74       <literal>FIELD=VALUE</literal>,
  75       e.g. <literal>_SYSTEMD_UNIT=httpd.service</literal>, referring
  76       to the components of a structured journal entry. See
  77       <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
  78       for a list of well-known fields. If multiple matches are
  79       specified matching different fields, the log entries are
  80       filtered by both, i.e. the resulting output will show only
  81       entries matching all the specified matches of this kind. If two
  82       matches apply to the same field, then they are automatically
  83       matched as alternatives, i.e. the resulting output will show
  84       entries matching any of the specified matches for the same
  85       field. Finally, the character <literal>+</literal> may appear
  86       as a separate word between other terms on the command line. This
  87       causes all matches before and after to be combined in a
  88       disjunction (i.e. logical OR).</para>
  89
  90       <para>As shortcuts for a few types of field/value matches, file
  91       paths may be specified. If a file path refers to an executable
  92       file, this is equivalent to an <literal>_EXE=</literal> match
  93       for the canonicalized binary path. Similarly, if a path refers
  94       to a device node then match is added for the kernel name of the
  95       device (<literal>_KERNEL_DEVICE=</literal>). Also, matches for the
  96       kernel names of all the parent devices are added automatically.
  97       Device node paths are not stable across reboots, therefore match
  98       for the current boot id (<literal>_BOOT_ID=</literal>) is
  99       always added as well. Note that only the log entries for
 100       the existing device nodes maybe queried by providing path to
 101       the device node.</para>
 102
 103       <para>Additional constraints may be added using options
 104       <option>--boot</option>, <option>--unit=</option>, etc., to
 105       further limit what entries will be shown (logical AND).</para>
 106
 107       <para>Output is interleaved from all accessible journal files,
 108       whether they are rotated or currently being written, and
 109       regardless of whether they belong to the system itself or are
 110       accessible user journals.</para>
 111
 112       <para>The set of journal files which will be used can be
 113       modified using the <option>--user</option>,
 114       <option>--system</option>, <option>--directory</option>, and
 115       <option>--file</option> options, see below.</para>
 116
 117       <para>All users are granted access to their private per-user
 118       journals. However, by default, only root and users who are
 119       members of a few special groups are granted access to the system
 120       journal and the journals of other users. Members of the groups
 121       <literal>systemd-journal</literal>, <literal>adm</literal>, and
 122       <literal>wheel</literal> can read all journal files. Note
 123       that the two latter groups traditionally have additional
 124       privileges specified by the distribution. Members of the
 125       <literal>wheel</literal> group can often perform administrative
 126       tasks.</para>
 127
 128       <para>The output is paged through <command>less</command> by
 129       default, and long lines are "truncated" to screen width. The
 130       hidden part can be viewed by using the left-arrow and
 131       right-arrow keys. Paging can be disabled; see the
 132       <option>--no-pager</option> option and the "Environment" section
 133       below.</para>
 134
 135       <para>When outputting to a tty, lines are colored according to
 136       priority: lines of level ERROR and higher are colored red; lines
 137       of level NOTICE and higher are highlighted; other lines are
 138       displayed normally.</para>
 139     </refsect1>
 140
 141     <refsect1>
 142       <title>Options</title>
 143
 144       <para>The following options are understood:</para>
 145
 146       <variablelist>
 147         <varlistentry>
 148           <term><option>--no-full</option></term>
 149           <term><option>--full</option></term>
 150           <term><option>-l</option></term>
 151
 152           <listitem><para>Ellipsize fields when they do not fit in
 153           available columns.  The default is to show full fields,
 154           allowing them to wrap or be truncated by the pager, if one
 155           is used.</para>
 156
 157           <para>The old options
 158           <option>-l</option>/<option>--full</option> are not useful
 159           anymore, except to undo <option>--no-full</option>.</para>
 160           </listitem>
 161         </varlistentry>
 162
 163         <varlistentry>
 164           <term><option>-a</option></term>
 165           <term><option>--all</option></term>
 166
 167           <listitem><para>Show all fields in full, even if they
 168           include unprintable characters or are very
 169           long.</para></listitem>
 170         </varlistentry>
 171
 172         <varlistentry>
 173           <term><option>-f</option></term>
 174           <term><option>--follow</option></term>
 175
 176           <listitem><para>Show only the most recent journal entries,
 177           and continuously print new entries as they are appended to
 178           the journal.</para></listitem>
 179         </varlistentry>
 180
 181         <varlistentry>
 182           <term><option>-e</option></term>
 183           <term><option>--pager-end</option></term>
 184
 185           <listitem><para>Immediately jump to the end of the journal
 186           inside the implied pager tool. This implies
 187           <option>-n1000</option> to guarantee that the pager will not
 188           buffer logs of unbounded size. This may be overridden with
 189           an explicit <option>-n</option> with some other numeric
 190           value, while <option>-nall</option> will disable this cap.
 191           Note that this option is only supported for the
 192           <citerefentry project='man-pages'><refentrytitle>less</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 193           pager.</para></listitem>
 194         </varlistentry>
 195
 196         <varlistentry>
 197           <term><option>-n</option></term>
 198           <term><option>--lines=</option></term>
 199
 200           <listitem><para>Show the most recent journal events and
 201           limit the number of events shown. If
 202           <option>--follow</option> is used, this option is
 203           implied. The argument is a positive integer or
 204           <literal>all</literal> to disable line limiting. The default
 205           value is 10 if no argument is given.</para></listitem>
 206         </varlistentry>
 207
 208         <varlistentry>
 209           <term><option>--no-tail</option></term>
 210
 211           <listitem><para>Show all stored output lines, even in follow
 212           mode. Undoes the effect of <option>--lines=</option>.
 213           </para></listitem>
 214         </varlistentry>
 215
 216         <varlistentry>
 217           <term><option>-r</option></term>
 218           <term><option>--reverse</option></term>
 219
 220           <listitem><para>Reverse output so that the newest entries
 221           are displayed first.</para></listitem>
 222         </varlistentry>
 223
 224         <varlistentry>
 225           <term><option>-o</option></term>
 226           <term><option>--output=</option></term>
 227
 228           <listitem><para>Controls the formatting of the journal
 229           entries that are shown. Takes one of the following
 230           options:</para>
 231           <variablelist>
 232             <varlistentry>
 233               <term>
 234                 <option>short</option>
 235               </term>
 236               <listitem>
 237                 <para>is the default and generates an output that is
 238                 mostly identical to the formatting of classic syslog
 239                 files, showing one line per journal entry.</para>
 240               </listitem>
 241             </varlistentry>
 242
 243             <varlistentry>
 244               <term>
 245                 <option>short-iso</option>
 246               </term>
 247               <listitem>
 248                 <para>is very similar, but shows ISO 8601 wallclock
 249                 timestamps.</para>
 250               </listitem>
 251             </varlistentry>
 252
 253             <varlistentry>
 254               <term>
 255                 <option>short-precise</option>
 256               </term>
 257               <listitem>
 258                 <para>is very similar, but shows timestamps with full
 259                 microsecond precision.</para>
 260               </listitem>
 261             </varlistentry>
 262
 263             <varlistentry>
 264               <term>
 265                 <option>short-monotonic</option>
 266               </term>
 267               <listitem>
 268                 <para>is very similar, but shows monotonic timestamps
 269                 instead of wallclock timestamps.</para>
 270               </listitem>
 271             </varlistentry>
 272
 273             <varlistentry>
 274               <term>
 275                 <option>short-unix</option>
 276               </term>
 277               <listitem>
 278                 <para>is very similar, but shows seconds passed since January 1st 1970 UTC instead of wallclock
 279                 timestamps ("UNIX time"). The time is shown with microsecond accuracy.</para>
 280               </listitem>
 281             </varlistentry>
 282
 283             <varlistentry>
 284               <term>
 285                 <option>verbose</option>
 286               </term>
 287               <listitem>
 288                 <para>shows the full-structured entry items with all
 289                 fields.</para>
 290               </listitem>
 291             </varlistentry>
 292
 293             <varlistentry>
 294               <term>
 295                 <option>export</option>
 296               </term>
 297               <listitem>
 298                 <para>serializes the journal into a binary (but mostly
 299                 text-based) stream suitable for backups and network
 300                 transfer (see
 301                 <ulink url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal Export Format</ulink>
 302                 for more information).</para>
 303               </listitem>
 304             </varlistentry>
 305
 306             <varlistentry>
 307               <term>
 308                 <option>json</option>
 309               </term>
 310               <listitem>
 311                 <para>formats entries as JSON data structures, one per
 312                 line (see
 313                 <ulink url="http://www.freedesktop.org/wiki/Software/systemd/json">Journal JSON Format</ulink>
 314                 for more information).</para>
 315               </listitem>
 316             </varlistentry>
 317
 318             <varlistentry>
 319               <term>
 320                 <option>json-pretty</option>
 321               </term>
 322               <listitem>
 323                 <para>formats entries as JSON data structures, but
 324                 formats them in multiple lines in order to make them
 325                 more readable by humans.</para>
 326               </listitem>
 327             </varlistentry>
 328
 329             <varlistentry>
 330               <term>
 331                 <option>json-sse</option>
 332               </term>
 333               <listitem>
 334                 <para>formats entries as JSON data structures, but wraps
 335                 them in a format suitable for
 336                 <ulink url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent Events</ulink>.
 337                 </para>
 338               </listitem>
 339             </varlistentry>
 340
 341             <varlistentry>
 342               <term>
 343                 <option>cat</option>
 344               </term>
 345               <listitem>
 346                 <para>generates a very terse output, only showing the
 347                 actual message of each journal entry with no metadata,
 348                 not even a timestamp.</para>
 349               </listitem>
 350             </varlistentry>
 351           </variablelist>
 352         </listitem>
 353       </varlistentry>
 354
 355       <varlistentry>
 356         <term><option>--utc</option></term>
 357
 358         <listitem><para>Express time in Coordinated Universal Time
 359         (UTC).</para></listitem>
 360       </varlistentry>
 361
 362       <varlistentry>
 363         <term><option>--no-hostname</option></term>
 364
 365         <listitem><para>Don't show the hostname field of log messages originating from the local host. This switch only
 366         has an effect on the <option>short</option> family of output modes (see above).</para></listitem>
 367       </varlistentry>
 368
 369       <varlistentry>
 370         <term><option>-x</option></term>
 371         <term><option>--catalog</option></term>
 372
 373         <listitem><para>Augment log lines with explanation texts from
 374         the message catalog. This will add explanatory help texts to
 375         log messages in the output where this is available. These
 376         short help texts will explain the context of an error or log
 377         event, possible solutions, as well as pointers to support
 378         forums, developer documentation, and any other relevant
 379         manuals. Note that help texts are not available for all
 380         messages, but only for selected ones. For more information on
 381         the message catalog, please refer to the
 382         <ulink url="http://www.freedesktop.org/wiki/Software/systemd/catalog">Message Catalog Developer Documentation</ulink>.</para>
 383
 384         <para>Note: when attaching <command>journalctl</command>
 385         output to bug reports, please do <emphasis>not</emphasis> use
 386         <option>-x</option>.</para>
 387         </listitem>
 388       </varlistentry>
 389
 390       <varlistentry>
 391         <term><option>-q</option></term>
 392         <term><option>--quiet</option></term>
 393
 394         <listitem><para>Suppresses all info messages
 395         (i.e. "-- Logs begin at ...", "-- Reboot --"),
 396         any warning messages regarding
 397         inaccessible system journals when run as a normal
 398         user.</para></listitem>
 399       </varlistentry>
 400
 401       <varlistentry>
 402         <term><option>-m</option></term>
 403         <term><option>--merge</option></term>
 404
 405         <listitem><para>Show entries interleaved from all available
 406         journals, including remote ones.</para></listitem>
 407       </varlistentry>
 408
 409       <varlistentry>
 410         <term><option>-b <optional><replaceable>ID</replaceable></optional><optional><replaceable>±offset</replaceable></optional></option></term>
 411         <term><option>--boot=<optional><replaceable>ID</replaceable></optional><optional><replaceable>±offset</replaceable></optional></option></term>
 412
 413         <listitem><para>Show messages from a specific boot. This will
 414         add a match for <literal>_BOOT_ID=</literal>.</para>
 415
 416         <para>The argument may be empty, in which case logs for the
 417         current boot will be shown.</para>
 418
 419         <para>If the boot ID is omitted, a positive
 420         <replaceable>offset</replaceable> will look up the boots
 421         starting from the beginning of the journal, and an
 422         equal-or-less-than zero <replaceable>offset</replaceable> will
 423         look up boots starting from the end of the journal. Thus,
 424         <constant>1</constant> means the first boot found in the
 425         journal in chronological order, <constant>2</constant> the
 426         second and so on; while <constant>-0</constant> is the last
 427         boot, <constant>-1</constant> the boot before last, and so
 428         on. An empty <replaceable>offset</replaceable> is equivalent
 429         to specifying <constant>-0</constant>, except when the current
 430         boot is not the last boot (e.g. because
 431         <option>--directory</option> was specified to look at logs
 432         from a different machine).</para>
 433
 434         <para>If the 32-character <replaceable>ID</replaceable> is
 435         specified, it may optionally be followed by
 436         <replaceable>offset</replaceable> which identifies the boot
 437         relative to the one given by boot
 438         <replaceable>ID</replaceable>. Negative values mean earlier
 439         boots and positive values mean later boots. If
 440         <replaceable>offset</replaceable> is not specified, a value of
 441         zero is assumed, and the logs for the boot given by
 442         <replaceable>ID</replaceable> are shown.</para>
 443         </listitem>
 444       </varlistentry>
 445
 446       <varlistentry>
 447         <term><option>--list-boots</option></term>
 448
 449         <listitem><para>Show a tabular list of boot numbers (relative to
 450         the current boot), their IDs, and the timestamps of the first
 451         and last message pertaining to the boot.</para></listitem>
 452       </varlistentry>
 453
 454       <varlistentry>
 455         <term><option>-k</option></term>
 456         <term><option>--dmesg</option></term>
 457
 458         <listitem><para>Show only kernel messages. This implies
 459         <option>-b</option> and adds the match
 460         <literal>_TRANSPORT=kernel</literal>.</para></listitem>
 461       </varlistentry>
 462
 463       <varlistentry>
 464         <term><option>-t</option></term>
 465         <term><option>--identifier=<replaceable>SYSLOG_IDENTIFIER</replaceable></option></term>
 466
 467         <listitem><para>Show messages for the specified syslog
 468         identifier
 469         <replaceable>SYSLOG_IDENTIFIER</replaceable>.</para>
 470
 471         <para>This parameter can be specified multiple
 472         times.</para></listitem>
 473       </varlistentry>
 474
 475       <varlistentry>
 476         <term><option>-u</option></term>
 477         <term><option>--unit=<replaceable>UNIT</replaceable>|<replaceable>PATTERN</replaceable></option></term>
 478
 479         <listitem><para>Show messages for the specified systemd unit
 480         <replaceable>UNIT</replaceable> (such as a service unit), or
 481         for any of the units matched by
 482         <replaceable>PATTERN</replaceable>.  If a pattern is
 483         specified, a list of unit names found in the journal is
 484         compared with the specified pattern and all that match are
 485         used. For each unit name, a match is added for messages from
 486         the unit
 487         (<literal>_SYSTEMD_UNIT=<replaceable>UNIT</replaceable></literal>),
 488         along with additional matches for messages from systemd and
 489         messages about coredumps for the specified unit.</para>
 490
 491         <para>This parameter can be specified multiple times.</para>
 492         </listitem>
 493       </varlistentry>
 494
 495       <varlistentry>
 496         <term><option>--user-unit=</option></term>
 497
 498         <listitem><para>Show messages for the specified user session
 499         unit. This will add a match for messages from the unit
 500         (<literal>_SYSTEMD_USER_UNIT=</literal> and
 501         <literal>_UID=</literal>) and additional matches for messages
 502         from session systemd and messages about coredumps for the
 503         specified unit.</para>
 504
 505         <para>This parameter can be specified multiple times.</para>
 506         </listitem>
 507       </varlistentry>
 508
 509       <varlistentry>
 510         <term><option>-p</option></term>
 511         <term><option>--priority=</option></term>
 512
 513         <listitem><para>Filter output by message priorities or
 514         priority ranges. Takes either a single numeric or textual log
 515         level (i.e. between 0/<literal>emerg</literal> and
 516         7/<literal>debug</literal>), or a range of numeric/text log
 517         levels in the form FROM..TO. The log levels are the usual
 518         syslog log levels as documented in
 519         <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 520         i.e. <literal>emerg</literal> (0),
 521         <literal>alert</literal> (1), <literal>crit</literal> (2),
 522         <literal>err</literal> (3), <literal>warning</literal> (4),
 523         <literal>notice</literal> (5), <literal>info</literal> (6),
 524         <literal>debug</literal> (7). If a single log level is
 525         specified, all messages with this log level or a lower (hence
 526         more important) log level are shown. If a range is specified,
 527         all messages within the range are shown, including both the
 528         start and the end value of the range. This will add
 529         <literal>PRIORITY=</literal> matches for the specified
 530         priorities.</para></listitem>
 531       </varlistentry>
 532
 533       <varlistentry>
 534         <term><option>-c</option></term>
 535         <term><option>--cursor=</option></term>
 536
 537         <listitem><para>Start showing entries from the location in the
 538         journal specified by the passed cursor.</para></listitem>
 539       </varlistentry>
 540
 541       <varlistentry>
 542         <term><option>--after-cursor=</option></term>
 543
 544         <listitem><para>Start showing entries from the location in the
 545         journal <emphasis>after</emphasis> the location specified by
 546         the passed cursor.  The cursor is shown when the
 547         <option>--show-cursor</option> option is used.</para>
 548         </listitem>
 549       </varlistentry>
 550
 551       <varlistentry>
 552         <term><option>--show-cursor</option></term>
 553
 554         <listitem><para>The cursor is shown after the last entry after
 555         two dashes:</para>
 556         <programlisting>-- cursor: s=0639...</programlisting>
 557         <para>The format of the cursor is private
 558         and subject to change.</para></listitem>
 559       </varlistentry>
 560
 561       <varlistentry>
 562         <term><option>-S</option></term>
 563         <term><option>--since=</option></term>
 564         <term><option>-U</option></term>
 565         <term><option>--until=</option></term>
 566
 567         <listitem><para>Start showing entries on or newer than the
 568         specified date, or on or older than the specified date,
 569         respectively. Date specifications should be of the format
 570         <literal>2012-10-30 18:17:16</literal>.  If the time part is
 571         omitted, <literal>00:00:00</literal> is assumed.  If only the
 572         seconds component is omitted, <literal>:00</literal> is
 573         assumed. If the date component is omitted, the current day is
 574         assumed. Alternatively the strings
 575         <literal>yesterday</literal>, <literal>today</literal>,
 576         <literal>tomorrow</literal> are understood, which refer to
 577         00:00:00 of the day before the current day, the current day,
 578         or the day after the current day,
 579         respectively. <literal>now</literal> refers to the current
 580         time. Finally, relative times may be specified, prefixed with
 581         <literal>-</literal> or <literal>+</literal>, referring to
 582         times before or after the current time, respectively. For complete
 583         time and date specification, see
 584         <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>.
 585         </para>
 586         </listitem>
 587       </varlistentry>
 588
 589       <varlistentry>
 590         <term><option>-F</option></term>
 591         <term><option>--field=</option></term>
 592
 593         <listitem><para>Print all possible data values the specified
 594         field can take in all entries of the journal.</para></listitem>
 595       </varlistentry>
 596
 597       <varlistentry>
 598         <term><option>-N</option></term>
 599         <term><option>--fields</option></term>
 600
 601         <listitem><para>Print all field names currently used in all entries of the journal.</para></listitem>
 602       </varlistentry>
 603
 604       <varlistentry>
 605         <term><option>--system</option></term>
 606         <term><option>--user</option></term>
 607
 608         <listitem><para>Show messages from system services and the
 609         kernel (with <option>--system</option>). Show messages from
 610         service of current user (with <option>--user</option>).  If
 611         neither is specified, show all messages that the user can see.
 612         </para></listitem>
 613       </varlistentry>
 614
 615       <varlistentry>
 616         <term><option>-M</option></term>
 617         <term><option>--machine=</option></term>
 618
 619         <listitem><para>Show messages from a running, local
 620         container. Specify a container name to connect to.</para>
 621         </listitem>
 622       </varlistentry>
 623
 624       <varlistentry>
 625         <term><option>-D <replaceable>DIR</replaceable></option></term>
 626         <term><option>--directory=<replaceable>DIR</replaceable></option></term>
 627
 628         <listitem><para>Takes a directory path as argument. If
 629         specified, journalctl will operate on the specified journal
 630         directory <replaceable>DIR</replaceable> instead of the
 631         default runtime and system journal paths.</para></listitem>
 632       </varlistentry>
 633
 634       <varlistentry>
 635         <term><option>--file=<replaceable>GLOB</replaceable></option></term>
 636
 637         <listitem><para>Takes a file glob as an argument. If
 638         specified, journalctl will operate on the specified journal
 639         files matching <replaceable>GLOB</replaceable> instead of the
 640         default runtime and system journal paths. May be specified
 641         multiple times, in which case files will be suitably
 642         interleaved.</para></listitem>
 643       </varlistentry>
 644
 645       <varlistentry>
 646         <term><option>--root=<replaceable>ROOT</replaceable></option></term>
 647
 648         <listitem><para>Takes a directory path as an argument. If
 649         specified, journalctl will operate on catalog file hierarchy
 650         underneath the specified directory instead of the root
 651         directory (e.g. <option>--update-catalog</option> will create
 652         <filename><replaceable>ROOT</replaceable>/var/lib/systemd/catalog/database</filename>).
 653         </para></listitem>
 654       </varlistentry>
 655
 656       <varlistentry>
 657         <term><option>--new-id128</option></term>
 658
 659         <listitem><para>Instead of showing journal contents, generate
 660         a new 128-bit ID suitable for identifying messages. This is
 661         intended for usage by developers who need a new identifier for
 662         a new message they introduce and want to make
 663         recognizable. This will print the new ID in three different
 664         formats which can be copied into source code or similar.
 665         </para></listitem>
 666       </varlistentry>
 667
 668       <varlistentry>
 669         <term><option>--header</option></term>
 670
 671         <listitem><para>Instead of showing journal contents, show
 672         internal header information of the journal fields
 673         accessed.</para></listitem>
 674       </varlistentry>
 675
 676       <varlistentry>
 677         <term><option>--disk-usage</option></term>
 678
 679         <listitem><para>Shows the current disk usage of all journal
 680         files. This shows the sum of the disk usage of all archived
 681         and active journal files.</para></listitem>
 682       </varlistentry>
 683
 684       <varlistentry>
 685         <term><option>--vacuum-size=</option></term>
 686         <term><option>--vacuum-time=</option></term>
 687         <term><option>--vacuum-files=</option></term>
 688
 689         <listitem><para>Removes archived journal files until the disk
 690         space they use falls below the specified size (specified with
 691         the usual <literal>K</literal>, <literal>M</literal>,
 692         <literal>G</literal> and <literal>T</literal> suffixes), or all
 693         archived journal files contain no data older than the specified
 694         timespan (specified with the usual <literal>s</literal>,
 695         <literal>m</literal>, <literal>h</literal>,
 696         <literal>days</literal>, <literal>months</literal>,
 697         <literal>weeks</literal> and <literal>years</literal> suffixes),
 698         or no more than the specified number of separate journal files
 699         remain. Note that running <option>--vacuum-size=</option> has
 700         only an indirect effect on the output shown by
 701         <option>--disk-usage</option>, as the latter includes active
 702         journal files, while the vacuuming operation only operates
 703         on archived journal files. Similarly,
 704         <option>--vacuum-files=</option> might not actually reduce the
 705         number of journal files to below the specified number, as it
 706         will not remove active journal
 707         files. <option>--vacuum-size=</option>,
 708         <option>--vacuum-time=</option> and
 709         <option>--vacuum-files=</option> may be combined in a single
 710         invocation to enforce any combination of a size, a time and a
 711         number of files limit on the archived journal
 712         files. Specifying any of these three parameters as zero is
 713         equivalent to not enforcing the specific limit, and is thus
 714         redundant.</para></listitem>
 715       </varlistentry>
 716
 717       <varlistentry>
 718         <term><option>--list-catalog
 719         <optional><replaceable>128-bit-ID...</replaceable></optional>
 720         </option></term>
 721
 722         <listitem><para>List the contents of the message catalog as a
 723         table of message IDs, plus their short description strings.
 724         </para>
 725
 726         <para>If any <replaceable>128-bit-ID</replaceable>s are
 727         specified, only those entries are shown.</para>
 728         </listitem>
 729       </varlistentry>
 730
 731       <varlistentry>
 732         <term><option>--dump-catalog
 733         <optional><replaceable>128-bit-ID...</replaceable></optional>
 734         </option></term>
 735
 736         <listitem><para>Show the contents of the message catalog, with
 737         entries separated by a line consisting of two dashes and the
 738         ID (the format is the same as <filename>.catalog</filename>
 739         files).</para>
 740
 741         <para>If any <replaceable>128-bit-ID</replaceable>s are
 742         specified, only those entries are shown.</para>
 743         </listitem>
 744       </varlistentry>
 745
 746       <varlistentry>
 747         <term><option>--update-catalog</option></term>
 748
 749         <listitem><para>Update the message catalog index. This command
 750         needs to be executed each time new catalog files are
 751         installed, removed, or updated to rebuild the binary catalog
 752         index.</para></listitem>
 753       </varlistentry>
 754
 755       <varlistentry>
 756         <term><option>--setup-keys</option></term>
 757
 758         <listitem><para>Instead of showing journal contents, generate
 759         a new key pair for Forward Secure Sealing (FSS). This will
 760         generate a sealing key and a verification key. The sealing key
 761         is stored in the journal data directory and shall remain on
 762         the host. The verification key should be stored
 763         externally. Refer to the <option>Seal=</option> option in
 764         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 765         for information on Forward Secure Sealing and for a link to a
 766         refereed scholarly paper detailing the cryptographic theory it
 767         is based on.</para></listitem>
 768       </varlistentry>
 769
 770       <varlistentry>
 771         <term><option>--force</option></term>
 772
 773         <listitem><para>When <option>--setup-keys</option> is passed
 774         and Forward Secure Sealing (FSS) has already been configured,
 775         recreate FSS keys.</para></listitem>
 776       </varlistentry>
 777
 778       <varlistentry>
 779         <term><option>--interval=</option></term>
 780
 781         <listitem><para>Specifies the change interval for the sealing
 782         key when generating an FSS key pair with
 783         <option>--setup-keys</option>. Shorter intervals increase CPU
 784         consumption but shorten the time range of undetectable journal
 785         alterations. Defaults to 15min.</para></listitem>
 786       </varlistentry>
 787
 788       <varlistentry>
 789         <term><option>--verify</option></term>
 790
 791         <listitem><para>Check the journal file for internal
 792         consistency. If the file has been generated with FSS enabled and
 793         the FSS verification key has been specified with
 794         <option>--verify-key=</option>, authenticity of the journal file
 795         is verified.</para></listitem>
 796       </varlistentry>
 797
 798       <varlistentry>
 799         <term><option>--verify-key=</option></term>
 800
 801         <listitem><para>Specifies the FSS verification key to use for
 802         the <option>--verify</option> operation.</para></listitem>
 803       </varlistentry>
 804
 805       <varlistentry>
 806         <term><option>--sync</option></term>
 807
 808         <listitem><para>Asks the journal daemon to write all yet
 809         unwritten journal data to the backing file system and
 810         synchronize all journals. This call does not return until the
 811         synchronization operation is complete. This command guarantees
 812         that any log messages written before its invocation are safely
 813         stored on disk at the time it returns.</para></listitem>
 814       </varlistentry>
 815
 816       <varlistentry>
 817         <term><option>--flush</option></term>
 818
 819         <listitem><para>Asks the journal daemon to flush any log data
 820         stored in <filename>/run/log/journal</filename> into
 821         <filename>/var/log/journal</filename>, if persistent storage
 822         is enabled. This call does not return until the operation is
 823         complete. Note that this call is idempotent: the data is only
 824         flushed from <filename>/run/log/journal</filename> into
 825         <filename>/var/log/journal</filename> once during system
 826         runtime, and this command exits cleanly without executing any
 827         operation if this has already has happened. This command
 828         effectively guarantees that all data is flushed to
 829         <filename>/var/log/journal</filename> at the time it
 830         returns.</para></listitem>
 831       </varlistentry>
 832
 833       <varlistentry>
 834         <term><option>--rotate</option></term>
 835
 836         <listitem><para>Asks the journal daemon to rotate journal
 837         files. This call does not return until the rotation operation
 838         is complete.</para></listitem>
 839       </varlistentry>
 840
 841       <xi:include href="standard-options.xml" xpointer="help" />
 842       <xi:include href="standard-options.xml" xpointer="version" />
 843       <xi:include href="standard-options.xml" xpointer="no-pager" />
 844     </variablelist>
 845   </refsect1>
 846
 847   <refsect1>
 848     <title>Exit status</title>
 849
 850     <para>On success, 0 is returned; otherwise, a non-zero failure
 851     code is returned.</para>
 852   </refsect1>
 853
 854   <xi:include href="less-variables.xml" />
 855
 856   <refsect1>
 857     <title>Examples</title>
 858
 859     <para>Without arguments, all collected logs are shown
 860     unfiltered:</para>
 861
 862     <programlisting>journalctl</programlisting>
 863
 864     <para>With one match specified, all entries with a field matching
 865     the expression are shown:</para>
 866
 867     <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
 868
 869     <para>If two different fields are matched, only entries matching
 870     both expressions at the same time are shown:</para>
 871
 872     <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
 873
 874     <para>If two matches refer to the same field, all entries matching
 875     either expression are shown:</para>
 876
 877     <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
 878
 879     <para>If the separator <literal>+</literal> is used, two
 880     expressions may be combined in a logical OR. The following will
 881     show all messages from the Avahi service process with the PID
 882     28097 plus all messages from the D-Bus service (from any of its
 883     processes):</para>
 884
 885     <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
 886
 887     <para>Show all logs generated by the D-Bus executable:</para>
 888
 889     <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
 890
 891     <para>Show all kernel logs from previous boot:</para>
 892
 893     <programlisting>journalctl -k -b -1</programlisting>
 894
 895     <para>Show a live log display from a system service
 896     <filename>apache.service</filename>:</para>
 897
 898     <programlisting>journalctl -f -u apache</programlisting>
 899
 900   </refsect1>
 901
 902   <refsect1>
 903     <title>See Also</title>
 904     <para>
 905       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 906       <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 907       <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 908       <citerefentry><refentrytitle>coredumpctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 909       <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 910       <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 911       <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>
 912     </para>
 913   </refsect1>
 914 </refentry>