man/journalctl.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
   5 <!--
   6   This file is part of systemd.
   7
   8   Copyright 2012 Lennart Poettering
   9
  10   systemd is free software; you can redistribute it and/or modify it
  11   under the terms of the GNU Lesser General Public License as published by
  12   the Free Software Foundation; either version 2.1 of the License, or
  13   (at your option) any later version.
  14
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  18   Lesser General Public License for more details.
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  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
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  23
  24 <refentry id="journalctl">
  25
  26         <refentryinfo>
  27                 <title>journalctl</title>
  28                 <productname>systemd</productname>
  29
  30                 <authorgroup>
  31                         <author>
  32                                 <contrib>Developer</contrib>
  33                                 <firstname>Lennart</firstname>
  34                                 <surname>Poettering</surname>
  35                                 <email>lennart@poettering.net</email>
  36                         </author>
  37                 </authorgroup>
  38         </refentryinfo>
  39
  40         <refmeta>
  41                 <refentrytitle>journalctl</refentrytitle>
  42                 <manvolnum>1</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>journalctl</refname>
  47                 <refpurpose>Query the systemd journal</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <cmdsynopsis>
  52                         <command>journalctl</command>
  53                         <arg choice="opt" rep="repeat">OPTIONS</arg>
  54                         <arg choice="opt" rep="repeat">MATCHES</arg>
  55                 </cmdsynopsis>
  56         </refsynopsisdiv>
  57
  58         <refsect1>
  59                 <title>Description</title>
  60
  61                 <para><command>journalctl</command> may be used to
  62                 query the contents of the
  63                 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  64                 journal as written by
  65                 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
  66
  67                 <para>If called without parameters, it will show the full
  68                 contents of the journal, starting with the oldest
  69                 entry collected.</para>
  70
  71                 <para>If one or more match arguments are passed, the
  72                 output is filtered accordingly. A match is in the
  73                 format <literal>FIELD=VALUE</literal>,
  74                 e.g. <literal>_SYSTEMD_UNIT=httpd.service</literal>,
  75                 referring to the components of a structured journal
  76                 entry. See
  77                 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
  78                 for a list of well-known fields. If multiple matches
  79                 are specified matching different fields, the log
  80                 entries are filtered by both, i.e. the resulting output
  81                 will show only entries matching all the specified
  82                 matches of this kind. If two matches apply to the same
  83                 field, then they are automatically matched as
  84                 alternatives, i.e. the resulting output will show
  85                 entries matching any of the specified matches for the
  86                 same field. Finally, if the character
  87                 <literal>+</literal> appears as separate word on the
  88                 command line, all matches before and after are combined
  89                 in a disjunction (i.e. logical OR).</para>
  90
  91                 <para>As shortcuts for a few types of field/value
  92                 matches, file paths may be specified. If a file path
  93                 refers to an executable file, this is equivalent to an
  94                 <literal>_EXE=</literal> match for the canonicalized
  95                 binary path. Similarly, if a path refers to a device
  96                 node, this is equivalent to a
  97                 <literal>_KERNEL_DEVICE=</literal> match for the
  98                 device.</para>
  99
 100                 <para>Output is interleaved from all accessible
 101                 journal files, whether they are rotated or currently
 102                 being written, and regardless of whether they belong to the
 103                 system itself or are accessible user journals.</para>
 104
 105                 <para>All users are granted access to their private
 106                 per-user journals. However, by default, only root and
 107                 users who are members of the <literal>systemd-journal</literal>
 108                 group get access to the system journal and the
 109                 journals of other users.</para>
 110
 111                 <para>The output is paged through
 112                 <command>less</command> by default, and long lines are
 113                 "truncated" to screen width. The hidden part can be
 114                 viewed by using the left-arrow and right-arrow
 115                 keys. Paging can be disabled, see
 116                 <option>--no-pager</option> and section Environment
 117                 below.</para>
 118
 119                 <para>When outputing to a tty, lines are colored
 120                 according to priority: lines of level ERROR and higher
 121                 are colored red, lines of level NOTICE and higher are
 122                 highlighted, and other lines are displayed normally.
 123                 </para>
 124         </refsect1>
 125
 126         <refsect1>
 127                 <title>Options</title>
 128
 129                 <para>The following options are understood:</para>
 130
 131                 <variablelist>
 132                         <varlistentry>
 133                                 <term><option>-h</option></term>
 134                                 <term><option>--help</option></term>
 135
 136                                 <listitem><para>Prints a short help
 137                                 text and exits.</para></listitem>
 138                         </varlistentry>
 139
 140                         <varlistentry>
 141                                 <term><option>--version</option></term>
 142
 143                                 <listitem><para>Prints a short version
 144                                 string and exits.</para></listitem>
 145                         </varlistentry>
 146
 147                         <varlistentry>
 148                                 <term><option>--no-pager</option></term>
 149
 150                                 <listitem><para>Do not pipe output into a
 151                                 pager.</para></listitem>
 152                         </varlistentry>
 153
 154                         <varlistentry>
 155                                 <term><option>--no-full</option></term>
 156                                 <term><option>--full</option></term>
 157                                 <term><option>-l</option></term>
 158
 159                                 <listitem><para>Ellipsize fields when
 160                                 they don't fit in available columns.
 161                                 The default is to show full fields,
 162                                 allowing them to wrap or be truncated
 163                                 by the pager if one is used.</para>
 164
 165                                 <para>Old options
 166                                 <option>-l</option>/<option>--full</option>
 167                                 not useful anymore, except to undo
 168                                 <option>--no-full</option>.</para></listitem>
 169                         </varlistentry>
 170
 171                         <varlistentry>
 172                                 <term><option>-a</option></term>
 173                                 <term><option>--all</option></term>
 174
 175                                 <listitem><para>Show all fields in
 176                                 full, even if they include unprintable
 177                                 characters or are very
 178                                 long.</para></listitem>
 179                         </varlistentry>
 180
 181                         <varlistentry>
 182                                 <term><option>-f</option></term>
 183                                 <term><option>--follow</option></term>
 184
 185                                 <listitem><para>Show only the most recent
 186                                 journal entries, and continuously print
 187                                 new entries as they are appended to
 188                                 the journal.</para></listitem>
 189                         </varlistentry>
 190
 191                         <varlistentry>
 192                                 <term><option>-e</option></term>
 193                                 <term><option>--pager-end</option></term>
 194
 195                                 <listitem><para>Immediately jump to
 196                                 the end of the journal inside the
 197                                 implied pager tool. This implies
 198                                 <option>-n1000</option> to guarantee
 199                                 that the pager will not buffer logs of
 200                                 unbounded size. This may be overridden
 201                                 with an explicit <option>-n</option>
 202                                 with some other numeric value on the
 203                                 command line. Note that this option is
 204                                 only supported for the
 205                                 <citerefentry><refentrytitle>less</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 206                                 pager.</para></listitem>
 207                         </varlistentry>
 208
 209                         <varlistentry>
 210                                 <term><option>-n</option></term>
 211                                 <term><option>--lines=</option></term>
 212
 213                                 <listitem><para>Show the most recent
 214                                 journal events and limit the number of
 215                                 events shown. If
 216                                 <option>--follow</option> is used,
 217                                 this option is implied. The argument,
 218                                 a positive integer, is optional, and
 219                                 defaults to 10. </para></listitem>
 220                         </varlistentry>
 221
 222                         <varlistentry>
 223                                 <term><option>--no-tail</option></term>
 224
 225                                 <listitem><para>Show all stored output
 226                                 lines, even in follow mode. Undoes the
 227                                 effect of
 228                                 <option>--lines=</option>.</para></listitem>
 229                         </varlistentry>
 230
 231                         <varlistentry>
 232                                 <term><option>-r</option></term>
 233                                 <term><option>--reverse</option></term>
 234
 235                                 <listitem><para>Reverse output, so the newest
 236                                 entries are displayed first.</para></listitem>
 237                         </varlistentry>
 238
 239                         <varlistentry>
 240                                 <term><option>-o</option></term>
 241                                 <term><option>--output=</option></term>
 242
 243                                 <listitem><para>Controls the
 244                                 formatting of the journal entries that
 245                                 are shown. Takes one of the following options:
 246                                 </para>
 247                                 <variablelist>
 248                                         <varlistentry>
 249                                                 <term>
 250                                                         <option>short</option>
 251                                                 </term>
 252                                                 <listitem>
 253                                                         <para>is the default
 254                                                         and generates an output
 255                                                         that is mostly identical
 256                                                         to the formatting of
 257                                                         classic syslog files,
 258                                                         showing one line per
 259                                                         journal entry.</para>
 260                                                 </listitem>
 261                                         </varlistentry>
 262
 263                                         <varlistentry>
 264                                                 <term>
 265                                                         <option>short-iso</option>
 266                                                 </term>
 267                                                 <listitem>
 268                                                         <para>is very similar,
 269                                                         but shows ISO 8601
 270                                                         wallclock timestamps.
 271                                                         </para>
 272                                                 </listitem>
 273                                         </varlistentry>
 274
 275                                         <varlistentry>
 276                                                 <term>
 277                                                         <option>short-precise</option>
 278                                                 </term>
 279                                                 <listitem>
 280                                                         <para>is very similar,
 281                                                         but shows timestamps
 282                                                         with full microsecond
 283                                                         precision.
 284                                                         </para>
 285                                                 </listitem>
 286                                         </varlistentry>
 287
 288                                         <varlistentry>
 289                                                 <term>
 290                                                         <option>short-monotonic</option>
 291                                                 </term>
 292                                                 <listitem>
 293                                                         <para>is very similar,
 294                                                         but shows monotonic
 295                                                         timestamps instead of
 296                                                         wallclock timestamps.
 297                                                         </para>
 298                                                 </listitem>
 299                                         </varlistentry>
 300
 301                                         <varlistentry>
 302                                                 <term>
 303                                                         <option>verbose</option>
 304                                                 </term>
 305                                                 <listitem>
 306                                                         <para>shows the
 307                                                         full-structured entry
 308                                                         items with all fields.
 309                                                         </para>
 310                                                 </listitem>
 311                                         </varlistentry>
 312
 313                                         <varlistentry>
 314                                                 <term>
 315                                                         <option>export</option>
 316                                                 </term>
 317                                                 <listitem>
 318                                                         <para>serializes the
 319                                                         journal into a binary
 320                                                         (but mostly text-based)
 321                                                         stream suitable for
 322                                                         backups and network
 323                                                         transfer (see <ulink
 324                                                         url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal
 325                                                         Export Format</ulink>
 326                                                         for more
 327                                                         information).</para>
 328                                                 </listitem>
 329                                         </varlistentry>
 330
 331                                         <varlistentry>
 332                                                 <term>
 333                                                         <option>json</option>
 334                                                 </term>
 335                                                 <listitem>
 336                                                         <para>formats entries
 337                                                         as JSON data structures,
 338                                                         one per line (see <ulink
 339                                                         url="http://www.freedesktop.org/wiki/Software/systemd/json">Journal
 340                                                         JSON Format</ulink> for
 341                                                         more information).</para>
 342                                                 </listitem>
 343                                         </varlistentry>
 344
 345                                         <varlistentry>
 346                                                 <term>
 347                                                         <option>json-pretty</option>
 348                                                 </term>
 349                                                 <listitem>
 350                                                         <para>formats entries as
 351                                                         JSON data structures,
 352                                                         but formats them in
 353                                                         multiple lines in order
 354                                                         to make them more
 355                                                         readable for humans.</para>
 356                                                 </listitem>
 357                                         </varlistentry>
 358
 359                                         <varlistentry>
 360                                                 <term>
 361                                                         <option>json-sse</option>
 362                                                 </term>
 363                                                 <listitem>
 364                                                         <para>formats entries as
 365                                                         JSON data structures,
 366                                                         but wraps them in a
 367                                                         format suitable for <ulink
 368                                                         url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent
 369                                                         Events</ulink>.</para>
 370                                                 </listitem>
 371                                         </varlistentry>
 372
 373                                         <varlistentry>
 374                                                 <term>
 375                                                         <option>cat</option>
 376                                                 </term>
 377                                                 <listitem>
 378                                                         <para>generates a very
 379                                                         terse output only
 380                                                         showing the actual
 381                                                         message of each journal
 382                                                         entry with no meta data,
 383                                                         not even a timestamp.
 384                                                         </para>
 385                                                 </listitem>
 386                                         </varlistentry>
 387                                 </variablelist>
 388                                 </listitem>
 389                         </varlistentry>
 390
 391                         <varlistentry>
 392                                 <term><option>-x</option></term>
 393                                 <term><option>--catalog</option></term>
 394
 395                                 <listitem><para>Augment log lines with
 396                                 explanation texts from the message
 397                                 catalog. This will add explanatory
 398                                 help texts to log messages in the
 399                                 output where this is available. These
 400                                 short help texts will explain the
 401                                 context of an error or log event,
 402                                 possible solutions, as well as
 403                                 pointers to support forums, developer
 404                                 documentation, and any other relevant
 405                                 manuals. Note that help texts are not
 406                                 available for all messages, but only
 407                                 for selected ones. For more
 408                                 information on the message catalog,
 409                                 please refer to the <ulink
 410                                 url="http://www.freedesktop.org/wiki/Software/systemd/catalog">Message
 411                                 Catalog Developer
 412                                 Documentation</ulink>.</para>
 413
 414                                 <para>Note: when attaching
 415                                 <command>journalctl</command> output
 416                                 to bug reports, please do
 417                                 <emphasis>not</emphasis> use
 418                                 <option>-x</option>.</para>
 419                                 </listitem>
 420                         </varlistentry>
 421
 422                         <varlistentry>
 423                                 <term><option>-q</option></term>
 424                                 <term><option>--quiet</option></term>
 425
 426                                 <listitem><para>Suppresses any warning
 427                                 message regarding inaccessible system
 428                                 journals when run as normal
 429                                 user.</para></listitem>
 430                         </varlistentry>
 431
 432                         <varlistentry>
 433                                 <term><option>-m</option></term>
 434                                 <term><option>--merge</option></term>
 435
 436                                 <listitem><para>Show entries
 437                                 interleaved from all available
 438                                 journals, including remote
 439                                 ones.</para></listitem>
 440                         </varlistentry>
 441
 442                         <varlistentry>
 443                                 <term><option>-b <optional><replaceable>ID</replaceable></optional><optional><replaceable>±offset</replaceable></optional></option></term>
 444                                 <term><option>--boot=<optional><replaceable>ID</replaceable></optional><optional><replaceable>±offset</replaceable></optional></option></term>
 445
 446                                 <listitem><para>Show messages from a specific
 447                                 boot. This will add a match for
 448                                 <literal>_BOOT_ID=</literal>.</para>
 449
 450                                 <para>The argument may be empty, in which case
 451                                 logs for the current boot will be shown.</para>
 452
 453                                 <para>If the boot ID is omitted, a positive
 454                                 <replaceable>offset</replaceable> will look up
 455                                 the boots starting from the beginning of the
 456                                 journal, and a equal-or-less-than zero
 457                                 <replaceable>offset</replaceable> will look up
 458                                 boots starting from the end of the
 459                                 journal. Thus, <constant>1</constant> means the
 460                                 first boot found in the journal in the
 461                                 chronological order, <constant>2</constant> the
 462                                 second and so on; while <constant>-0</constant>
 463                                 is the last boot, <constant>-1</constant> the
 464                                 boot before that, and so on. An empty
 465                                 <replaceable>offset</replaceable> is equivalent
 466                                 to specifying <constant>-0</constant>, except
 467                                 when the current boot is not the last boot
 468                                 (e.g. because <option>--directory</option> was
 469                                 specified to look at logs from a different
 470                                 machine).</para>
 471
 472                                 <para>If the 32 character
 473                                 <replaceable>ID</replaceable> is specified, it
 474                                 may optionally be followed by
 475                                 <replaceable>offset</replaceable> which
 476                                 identifies the boot relative to the one given by
 477                                 boot <replaceable>ID</replaceable>. Negative
 478                                 values mean earlier boots and a positive values
 479                                 mean later boots. If
 480                                 <replaceable>offset</replaceable> is not
 481                                 specified, a value of zero is assumed and the
 482                                 logs for the boot given by
 483                                 <replaceable>ID</replaceable> are shown.
 484                                 </para>
 485
 486                                 </listitem>
 487                         </varlistentry>
 488
 489                         <varlistentry>
 490                                 <term><option>-k</option></term>
 491                                 <term><option>--dmesg</option></term>
 492
 493                                 <listitem><para>Show only kernel messages. This
 494                                 implies <option>-b</option> and adds the match
 495                                 <literal>_TRANSPORT=kernel</literal>.
 496                                 </para></listitem>
 497                         </varlistentry>
 498
 499                         <varlistentry>
 500                                 <term><option>-u</option></term>
 501                                 <term><option>--unit=</option></term>
 502
 503                                 <listitem><para>Show messages for the
 504                                 specified systemd unit. This will add
 505                                 a match for messages from the unit
 506                                 (<literal>_SYSTEMD_UNIT=</literal>)
 507                                 and additional matches for messages
 508                                 from systemd and messages about
 509                                 coredumps for the specified unit.</para>
 510                                 <para>This parameter can be specified multiple times.
 511                                 </para></listitem>
 512                         </varlistentry>
 513
 514                         <varlistentry>
 515                                 <term><option>--user-unit=</option></term>
 516
 517                                 <listitem><para>Show messages for the
 518                                 specified user session unit. This will
 519                                 add a match for messages from the unit
 520                                 (<literal>_SYSTEMD_USER_UNIT=</literal>
 521                                 and <literal>_UID=</literal>) and
 522                                 additional matches for messages from
 523                                 session systemd and messages about
 524                                 coredumps for the specified unit.</para>
 525                                 <para>This parameter can be specified multiple times.
 526                                 </para></listitem>
 527                         </varlistentry>
 528
 529                         <varlistentry>
 530                                 <term><option>-p</option></term>
 531                                 <term><option>--priority=</option></term>
 532
 533                                 <listitem><para>Filter output by
 534                                 message priorities or priority
 535                                 ranges. Takes either a single numeric
 536                                 or textual log level (i.e. between
 537                                 0/<literal>emerg</literal> and
 538                                 7/<literal>debug</literal>), or a
 539                                 range of numeric/text log levels in
 540                                 the form FROM..TO. The log levels are
 541                                 the usual syslog log levels as
 542                                 documented in
 543                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 544                                 i.e. <literal>emerg</literal> (0),
 545                                 <literal>alert</literal> (1),
 546                                 <literal>crit</literal> (2),
 547                                 <literal>err</literal> (3),
 548                                 <literal>warning</literal> (4),
 549                                 <literal>notice</literal> (5),
 550                                 <literal>info</literal> (6),
 551                                 <literal>debug</literal> (7). If a
 552                                 single log level is specified, all
 553                                 messages with this log level or a
 554                                 lower (hence more important) log level
 555                                 are shown. If a range is specified, all
 556                                 messages within the range are shown,
 557                                 including both the start and the end
 558                                 value of the range. This will add
 559                                 <literal>PRIORITY=</literal> matches
 560                                 for the specified
 561                                 priorities.</para></listitem>
 562                         </varlistentry>
 563
 564                         <varlistentry>
 565                                 <term><option>-c</option></term>
 566                                 <term><option>--cursor=</option></term>
 567
 568                                 <listitem><para>Start showing entries
 569                                 from the location in the journal
 570                                 specified by the passed
 571                                 cursor.</para></listitem>
 572                         </varlistentry>
 573
 574                         <varlistentry>
 575                                 <term><option>--after-cursor=</option></term>
 576
 577                                 <listitem><para>Start showing entries from the
 578                                 location in the journal
 579                                 <emphasis>after</emphasis> the location
 580                                 specified by the this cursor.
 581                                 </para></listitem>
 582                         </varlistentry>
 583
 584                         <varlistentry>
 585                                 <term><option>--since=</option></term>
 586                                 <term><option>--until=</option></term>
 587
 588                                 <listitem><para>Start showing entries
 589                                 on or newer than the specified date,
 590                                 or on or older than the specified
 591                                 date, respectively. Date specifications
 592                                 should be of the format
 593                                 <literal>2012-10-30 18:17:16</literal>.
 594                                 If the time part is omitted,
 595                                 <literal>00:00:00</literal> is assumed.
 596                                 If only the seconds component is omitted,
 597                                 <literal>:00</literal> is assumed. If the
 598                                 date component is omitted, the current
 599                                 day is assumed. Alternatively the strings
 600                                 <literal>yesterday</literal>,
 601                                 <literal>today</literal>,
 602                                 <literal>tomorrow</literal> are
 603                                 understood, which refer to 00:00:00 of
 604                                 the day before the current day, the
 605                                 current day, or the day after the
 606                                 current day, respectively. <literal>now</literal>
 607                                 refers to the current time. Finally,
 608                                 relative times may be specified,
 609                                 prefixed with <literal>-</literal> or
 610                                 <literal>+</literal>, referring to
 611                                 times before or after the current
 612                                 time, respectively.</para></listitem>
 613                         </varlistentry>
 614
 615                         <varlistentry>
 616                                 <term><option>-F</option></term>
 617                                 <term><option>--field=</option></term>
 618
 619                                 <listitem><para>Print all possible
 620                                 data values the specified field can
 621                                 take in all entries of the
 622                                 journal.</para></listitem>
 623                         </varlistentry>
 624
 625                         <varlistentry>
 626                                 <term><option>--system</option></term>
 627                                 <term><option>--user</option></term>
 628
 629                                 <listitem><para>Show messages from
 630                                 system services and the kernel (with
 631                                 <option>--system</option>).  Show
 632                                 messages from service of current user
 633                                 (with <option>--user</option>).
 634                                 If neither is specified, show all
 635                                 messages that the user can see.
 636                                 </para></listitem>
 637                         </varlistentry>
 638
 639                         <varlistentry>
 640                                 <term><option>-D <replaceable>DIR</replaceable></option></term>
 641                                 <term><option>--directory=<replaceable>DIR</replaceable></option></term>
 642
 643                                 <listitem><para>Takes a directory path
 644                                 as argument. If specified, journalctl
 645                                 will operate on the specified journal
 646                                 directory
 647                                 <replaceable>DIR</replaceable> instead
 648                                 of the default runtime and system
 649                                 journal paths.</para></listitem>
 650                         </varlistentry>
 651
 652                         <varlistentry>
 653                                 <term><option>--file=<replaceable>GLOB</replaceable></option></term>
 654
 655                                 <listitem><para>Takes a file glob as
 656                                 argument. If specified, journalctl will
 657                                 operate on the specified journal files
 658                                 matching <replaceable>GLOB</replaceable>
 659                                 instead of the default runtime and
 660                                 system journal paths. May be specified
 661                                 multiple times, in which case files will
 662                                 be suitably interleaved.</para></listitem>
 663                         </varlistentry>
 664
 665                         <varlistentry>
 666                                 <term><option>--root=<replaceable>ROOT</replaceable></option></term>
 667
 668                                 <listitem><para>Takes a directory path
 669                                 as argument. If specified, journalctl
 670                                 will operate on catalog file hierarchy
 671                                 underneath the specified directory
 672                                 instead of the root directory
 673                                 (e.g. <option>--update-catalog</option>
 674                                 will create
 675                                 <filename><replaceable>ROOT</replaceable>/var/lib/systemd/catalog/database</filename>).
 676                                 </para></listitem>
 677                         </varlistentry>
 678
 679                         <varlistentry>
 680                                 <term><option>--new-id128</option></term>
 681
 682                                 <listitem><para>Instead of showing
 683                                 journal contents, generate a new 128
 684                                 bit ID suitable for identifying
 685                                 messages. This is intended for usage
 686                                 by developers who need a new
 687                                 identifier for a new message they
 688                                 introduce and want to make
 689                                 recognizable. This will print the new ID in
 690                                 three different formats which can be
 691                                 copied into source code or
 692                                 similar.</para></listitem>
 693                         </varlistentry>
 694
 695                         <varlistentry>
 696                                 <term><option>--header</option></term>
 697
 698                                 <listitem><para>Instead of showing
 699                                 journal contents, show internal header
 700                                 information of the journal fields
 701                                 accessed.</para></listitem>
 702                         </varlistentry>
 703
 704                         <varlistentry>
 705                                 <term><option>--disk-usage</option></term>
 706
 707                                 <listitem><para>Shows the current disk
 708                                 usage of all
 709                                 journal files.</para></listitem>
 710                         </varlistentry>
 711
 712                         <varlistentry>
 713                                 <term><option>--list-catalog
 714                                 <optional><replaceable>ID128...</replaceable></optional>
 715                                 </option></term>
 716
 717                                 <listitem><para>List the contents of
 718                                 the message catalog, as table of
 719                                 message IDs plus their short
 720                                 description strings.</para>
 721
 722                                 <para>If any
 723                                 <replaceable>ID128</replaceable>s are
 724                                 specified, only those entries are shown.
 725                                 </para>
 726                                 </listitem>
 727                         </varlistentry>
 728
 729                         <varlistentry>
 730                                 <term><option>--dump-catalog
 731                                 <optional><replaceable>ID128...</replaceable></optional>
 732                                 </option></term>
 733
 734                                 <listitem><para>Show the contents of
 735                                 the message catalog, with entries
 736                                 separated by a line consisting of two
 737                                 dashes and the id (the format is the
 738                                 same as <filename>.catalog</filename>
 739                                 files.</para>
 740
 741                                 <para>If any
 742                                 <replaceable>ID128</replaceable>s are
 743                                 specified, only those entries are shown.
 744                                 </para>
 745                                 </listitem>
 746                         </varlistentry>
 747
 748                         <varlistentry>
 749                                 <term><option>--update-catalog</option></term>
 750
 751                                 <listitem><para>Update the message
 752                                 catalog index. This command needs to
 753                                 be executed each time new catalog
 754                                 files are installed, removed or
 755                                 updated to rebuild the binary catalog
 756                                 index.</para></listitem>
 757                         </varlistentry>
 758
 759                         <varlistentry>
 760                                 <term><option>--setup-keys</option></term>
 761
 762                                 <listitem><para>Instead of showing
 763                                 journal contents, generate a new key
 764                                 pair for Forward Secure Sealing
 765                                 (FSS). This will generate a sealing
 766                                 key and a verification key. The
 767                                 sealing key is stored in the journal
 768                                 data directory and shall remain on the
 769                                 host. The verification key should be
 770                                 stored externally. Also see the
 771                                 <option>Seal=</option> option in
 772                                 <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 773                                 for details.</para></listitem>
 774                         </varlistentry>
 775
 776                         <varlistentry>
 777                                 <term><option>--force</option></term>
 778
 779                                 <listitem><para>When --setup-keys is passed and
 780                                 Forward Secure Sealing has already been set up,
 781                                 recreate FSS keys.</para></listitem>
 782                         </varlistentry>
 783
 784                         <varlistentry>
 785                                 <term><option>--interval=</option></term>
 786
 787                                 <listitem><para>Specifies the change
 788                                 interval for the sealing key when
 789                                 generating an FSS key pair with
 790                                 <option>--setup-keys</option>. Shorter
 791                                 intervals increase CPU consumption but
 792                                 shorten the time range of
 793                                 undetectable journal
 794                                 alterations. Defaults to
 795                                 15min.</para></listitem>
 796                         </varlistentry>
 797
 798                         <varlistentry>
 799                                 <term><option>--verify</option></term>
 800
 801                                 <listitem><para>Check the journal file
 802                                 for internal consistency. If the
 803                                 file has been generated with FSS
 804                                 enabled and the FSS verification key
 805                                 has been specified with
 806                                 <option>--verify-key=</option>,
 807                                 authenticity of the journal file is
 808                                 verified.</para></listitem>
 809                         </varlistentry>
 810
 811                         <varlistentry>
 812                                 <term><option>--verify-key=</option></term>
 813
 814                                 <listitem><para>Specifies the FSS
 815                                 verification key to use for the
 816                                 <option>--verify</option>
 817                                 operation.</para></listitem>
 818                         </varlistentry>
 819
 820                 </variablelist>
 821         </refsect1>
 822
 823         <refsect1>
 824                 <title>Exit status</title>
 825
 826                 <para>On success, 0 is returned, a non-zero failure
 827                 code otherwise.</para>
 828         </refsect1>
 829
 830         <refsect1>
 831                 <title>Environment</title>
 832
 833                 <variablelist class='environment-variables'>
 834                         <varlistentry>
 835                                 <term><varname>$SYSTEMD_PAGER</varname></term>
 836                                 <listitem><para>Pager to use when
 837                                 <option>--no-pager</option> is not given;
 838                                 overrides <varname>$PAGER</varname>.  Setting
 839                                 this to an empty string or the value
 840                                 <literal>cat</literal> is equivalent to passing
 841                                 <option>--no-pager</option>.</para></listitem>
 842                         </varlistentry>
 843                 </variablelist>
 844         </refsect1>
 845
 846         <refsect1>
 847                 <title>Examples</title>
 848
 849                 <para>Without arguments, all collected logs are shown
 850                 unfiltered:</para>
 851
 852                 <programlisting>journalctl</programlisting>
 853
 854                 <para>With one match specified, all entries with a field matching the expression are shown:</para>
 855
 856                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
 857
 858                 <para>If two different fields are matched, only entries matching both expressions at the same time are shown:</para>
 859
 860                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
 861
 862                 <para>If two matches refer to the same field, all entries matching either expression are shown:</para>
 863
 864                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
 865
 866                 <para>If the separator <literal>+</literal> is used,
 867                 two expressions may be combined in a logical OR. The
 868                 following will show all messages from the Avahi
 869                 service process with the PID 28097 plus all messages
 870                 from the D-Bus service (from any of its
 871                 processes):</para>
 872
 873                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
 874
 875                 <para>Show all logs generated by the D-Bus executable:</para>
 876
 877                 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
 878
 879                 <para>Show all logs of the kernel device node <filename noindex='true'>/dev/sda</filename>:</para>
 880
 881                 <programlisting>journalctl /dev/sda</programlisting>
 882
 883                 <para>Show all kernel logs from previous boot:</para>
 884
 885                 <programlisting>journalctl -k -b -1</programlisting>
 886
 887         </refsect1>
 888
 889         <refsect1>
 890                 <title>See Also</title>
 891                 <para>
 892                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 893                         <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 894                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 895                         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 896                         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 897                 </para>
 898         </refsect1>
 899
 900 </refentry>