man/journalctl.xml

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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 a 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 the
 116                 <option>--no-pager</option> option and the "Environment"
 117                 section 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; 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 do not 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>The old options
 166                                 <option>-l</option>/<option>--full</option>
 167                                 are 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 that 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 by 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                                 messages regarding inaccessible system
 428                                 journals when run as a 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
 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 last, 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>--list-boots</option></term>
 491
 492                                 <listitem><para>Show a tabular list of
 493                                 boot numbers (relative to the current
 494                                 boot), their IDs, and the timestamps
 495                                 of the first and last message
 496                                 pertaining to the boot.
 497                                 </para></listitem>
 498                         </varlistentry>
 499
 500                         <varlistentry>
 501                                 <term><option>-k</option></term>
 502                                 <term><option>--dmesg</option></term>
 503
 504                                 <listitem><para>Show only kernel messages. This
 505                                 implies <option>-b</option> and adds the match
 506                                 <literal>_TRANSPORT=kernel</literal>.
 507                                 </para></listitem>
 508                         </varlistentry>
 509
 510                         <varlistentry>
 511                                 <term><option>-u</option></term>
 512                                 <term><option>--unit=</option></term>
 513
 514                                 <listitem><para>Show messages for the
 515                                 specified systemd unit. This will add
 516                                 a match for messages from the unit
 517                                 (<literal>_SYSTEMD_UNIT=</literal>)
 518                                 and additional matches for messages
 519                                 from systemd and messages about
 520                                 coredumps for the specified unit.</para>
 521                                 <para>This parameter can be specified multiple times.
 522                                 </para></listitem>
 523                         </varlistentry>
 524
 525                         <varlistentry>
 526                                 <term><option>--user-unit=</option></term>
 527
 528                                 <listitem><para>Show messages for the
 529                                 specified user session unit. This will
 530                                 add a match for messages from the unit
 531                                 (<literal>_SYSTEMD_USER_UNIT=</literal>
 532                                 and <literal>_UID=</literal>) and
 533                                 additional matches for messages from
 534                                 session systemd and messages about
 535                                 coredumps for the specified unit.</para>
 536                                 <para>This parameter can be specified multiple times.
 537                                 </para></listitem>
 538                         </varlistentry>
 539
 540                         <varlistentry>
 541                                 <term><option>-p</option></term>
 542                                 <term><option>--priority=</option></term>
 543
 544                                 <listitem><para>Filter output by
 545                                 message priorities or priority
 546                                 ranges. Takes either a single numeric
 547                                 or textual log level (i.e. between
 548                                 0/<literal>emerg</literal> and
 549                                 7/<literal>debug</literal>), or a
 550                                 range of numeric/text log levels in
 551                                 the form FROM..TO. The log levels are
 552                                 the usual syslog log levels as
 553                                 documented in
 554                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 555                                 i.e. <literal>emerg</literal> (0),
 556                                 <literal>alert</literal> (1),
 557                                 <literal>crit</literal> (2),
 558                                 <literal>err</literal> (3),
 559                                 <literal>warning</literal> (4),
 560                                 <literal>notice</literal> (5),
 561                                 <literal>info</literal> (6),
 562                                 <literal>debug</literal> (7). If a
 563                                 single log level is specified, all
 564                                 messages with this log level or a
 565                                 lower (hence more important) log level
 566                                 are shown. If a range is specified, all
 567                                 messages within the range are shown,
 568                                 including both the start and the end
 569                                 value of the range. This will add
 570                                 <literal>PRIORITY=</literal> matches
 571                                 for the specified
 572                                 priorities.</para></listitem>
 573                         </varlistentry>
 574
 575                         <varlistentry>
 576                                 <term><option>-c</option></term>
 577                                 <term><option>--cursor=</option></term>
 578
 579                                 <listitem><para>Start showing entries
 580                                 from the location in the journal
 581                                 specified by the passed
 582                                 cursor.</para></listitem>
 583                         </varlistentry>
 584
 585                         <varlistentry>
 586                                 <term><option>--after-cursor=</option></term>
 587
 588                                 <listitem><para>Start showing entries
 589                                 from the location in the journal
 590                                 <emphasis>after</emphasis> the
 591                                 location specified by the this cursor.
 592                                 The cursor is shown when the
 593                                 <option>--show-cursor</option> option
 594                                 is used.</para></listitem>
 595                         </varlistentry>
 596
 597                         <varlistentry>
 598                                 <term><option>--show-cursor</option></term>
 599
 600                                 <listitem><para>The cursor is shown after the last
 601                                 entry after two dashes:</para>
 602                                 <programlisting>-- cursor: s=0639...</programlisting>
 603                                 <para>The format of the cursor is private
 604                                 and subject to change.</para></listitem>
 605                         </varlistentry>
 606
 607                         <varlistentry>
 608                                 <term><option>--since=</option></term>
 609                                 <term><option>--until=</option></term>
 610
 611                                 <listitem><para>Start showing entries
 612                                 on or newer than the specified date,
 613                                 or on or older than the specified
 614                                 date, respectively. Date specifications
 615                                 should be of the format
 616                                 <literal>2012-10-30 18:17:16</literal>.
 617                                 If the time part is omitted,
 618                                 <literal>00:00:00</literal> is assumed.
 619                                 If only the seconds component is omitted,
 620                                 <literal>:00</literal> is assumed. If the
 621                                 date component is omitted, the current
 622                                 day is assumed. Alternatively the strings
 623                                 <literal>yesterday</literal>,
 624                                 <literal>today</literal>,
 625                                 <literal>tomorrow</literal> are
 626                                 understood, which refer to 00:00:00 of
 627                                 the day before the current day, the
 628                                 current day, or the day after the
 629                                 current day, respectively. <literal>now</literal>
 630                                 refers to the current time. Finally,
 631                                 relative times may be specified,
 632                                 prefixed with <literal>-</literal> or
 633                                 <literal>+</literal>, referring to
 634                                 times before or after the current
 635                                 time, respectively.</para></listitem>
 636                         </varlistentry>
 637
 638                         <varlistentry>
 639                                 <term><option>-F</option></term>
 640                                 <term><option>--field=</option></term>
 641
 642                                 <listitem><para>Print all possible
 643                                 data values the specified field can
 644                                 take in all entries of the
 645                                 journal.</para></listitem>
 646                         </varlistentry>
 647
 648                         <varlistentry>
 649                                 <term><option>--system</option></term>
 650                                 <term><option>--user</option></term>
 651
 652                                 <listitem><para>Show messages from
 653                                 system services and the kernel (with
 654                                 <option>--system</option>). Show
 655                                 messages from service of current user
 656                                 (with <option>--user</option>).
 657                                 If neither is specified, show all
 658                                 messages that the user can see.
 659                                 </para></listitem>
 660                         </varlistentry>
 661
 662                         <varlistentry>
 663                                 <term><option>-M</option></term>
 664                                 <term><option>--machine=</option></term>
 665
 666                                 <listitem><para>Show messages from a
 667                                 running, local container. Specify a
 668                                 container name to connect
 669                                 to.</para></listitem>
 670                         </varlistentry>
 671
 672                         <varlistentry>
 673                                 <term><option>-D <replaceable>DIR</replaceable></option></term>
 674                                 <term><option>--directory=<replaceable>DIR</replaceable></option></term>
 675
 676                                 <listitem><para>Takes a directory path
 677                                 as argument. If specified, journalctl
 678                                 will operate on the specified journal
 679                                 directory
 680                                 <replaceable>DIR</replaceable> instead
 681                                 of the default runtime and system
 682                                 journal paths.</para></listitem>
 683                         </varlistentry>
 684
 685                         <varlistentry>
 686                                 <term><option>--file=<replaceable>GLOB</replaceable></option></term>
 687
 688                                 <listitem><para>Takes a file glob as an
 689                                 argument. If specified, journalctl will
 690                                 operate on the specified journal files
 691                                 matching <replaceable>GLOB</replaceable>
 692                                 instead of the default runtime and
 693                                 system journal paths. May be specified
 694                                 multiple times, in which case files will
 695                                 be suitably interleaved.</para></listitem>
 696                         </varlistentry>
 697
 698                         <varlistentry>
 699                                 <term><option>--root=<replaceable>ROOT</replaceable></option></term>
 700
 701                                 <listitem><para>Takes a directory path
 702                                 as an argument. If specified, journalctl
 703                                 will operate on catalog file hierarchy
 704                                 underneath the specified directory
 705                                 instead of the root directory
 706                                 (e.g. <option>--update-catalog</option>
 707                                 will create
 708                                 <filename><replaceable>ROOT</replaceable>/var/lib/systemd/catalog/database</filename>).
 709                                 </para></listitem>
 710                         </varlistentry>
 711
 712                         <varlistentry>
 713                                 <term><option>--new-id128</option></term>
 714
 715                                 <listitem><para>Instead of showing
 716                                 journal contents, generate a new 128-bit
 717                                 ID suitable for identifying
 718                                 messages. This is intended for usage
 719                                 by developers who need a new
 720                                 identifier for a new message they
 721                                 introduce and want to make
 722                                 recognizable. This will print the new ID in
 723                                 three different formats which can be
 724                                 copied into source code or
 725                                 similar.</para></listitem>
 726                         </varlistentry>
 727
 728                         <varlistentry>
 729                                 <term><option>--header</option></term>
 730
 731                                 <listitem><para>Instead of showing
 732                                 journal contents, show internal header
 733                                 information of the journal fields
 734                                 accessed.</para></listitem>
 735                         </varlistentry>
 736
 737                         <varlistentry>
 738                                 <term><option>--disk-usage</option></term>
 739
 740                                 <listitem><para>Shows the current disk
 741                                 usage of all
 742                                 journal files.</para></listitem>
 743                         </varlistentry>
 744
 745                         <varlistentry>
 746                                 <term><option>--list-catalog
 747                                 <optional><replaceable>128-bit-ID...</replaceable></optional>
 748                                 </option></term>
 749
 750                                 <listitem><para>List the contents of
 751                                 the message catalog as a table of
 752                                 message IDs, plus their short
 753                                 description strings.</para>
 754
 755                                 <para>If any
 756                                 <replaceable>128-bit-ID</replaceable>s are
 757                                 specified, only those entries are shown.
 758                                 </para>
 759                                 </listitem>
 760                         </varlistentry>
 761
 762                         <varlistentry>
 763                                 <term><option>--dump-catalog
 764                                 <optional><replaceable>128-bit-ID...</replaceable></optional>
 765                                 </option></term>
 766
 767                                 <listitem><para>Show the contents of
 768                                 the message catalog, with entries
 769                                 separated by a line consisting of two
 770                                 dashes and the ID (the format is the
 771                                 same as <filename>.catalog</filename>
 772                                 files).</para>
 773
 774                                 <para>If any
 775                                 <replaceable>128-bit-ID</replaceable>s are
 776                                 specified, only those entries are shown.
 777                                 </para>
 778                                 </listitem>
 779                         </varlistentry>
 780
 781                         <varlistentry>
 782                                 <term><option>--update-catalog</option></term>
 783
 784                                 <listitem><para>Update the message
 785                                 catalog index. This command needs to
 786                                 be executed each time new catalog
 787                                 files are installed, removed, or
 788                                 updated to rebuild the binary catalog
 789                                 index.</para></listitem>
 790                         </varlistentry>
 791
 792                         <varlistentry>
 793                                 <term><option>--setup-keys</option></term>
 794
 795                                 <listitem><para>Instead of showing
 796                                 journal contents, generate a new key
 797                                 pair for Forward Secure Sealing
 798                                 (FSS). This will generate a sealing
 799                                 key and a verification key. The
 800                                 sealing key is stored in the journal
 801                                 data directory and shall remain on the
 802                                 host. The verification key should be
 803                                 stored externally. Refer to the
 804                                 <option>Seal=</option> option in
 805                                 <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 806                                 for information on Forward Secure
 807                                 Sealing and for a link to a refereed
 808                                 scholarly paper detailing the
 809                                 cryptographic theory it is based on.
 810                                 </para></listitem>
 811                         </varlistentry>
 812
 813                         <varlistentry>
 814                                 <term><option>--force</option></term>
 815
 816                                 <listitem><para>When
 817                                 <option>--setup-keys</option> is passed and
 818                                 Forward Secure Sealing (FSS) has already been
 819                                 configured, recreate FSS keys.</para></listitem>
 820                         </varlistentry>
 821
 822                         <varlistentry>
 823                                 <term><option>--interval=</option></term>
 824
 825                                 <listitem><para>Specifies the change
 826                                 interval for the sealing key when
 827                                 generating an FSS key pair with
 828                                 <option>--setup-keys</option>. Shorter
 829                                 intervals increase CPU consumption but
 830                                 shorten the time range of
 831                                 undetectable journal
 832                                 alterations. Defaults to
 833                                 15min.</para></listitem>
 834                         </varlistentry>
 835
 836                         <varlistentry>
 837                                 <term><option>--verify</option></term>
 838
 839                                 <listitem><para>Check the journal file
 840                                 for internal consistency. If the
 841                                 file has been generated with FSS
 842                                 enabled and the FSS verification key
 843                                 has been specified with
 844                                 <option>--verify-key=</option>,
 845                                 authenticity of the journal file is
 846                                 verified.</para></listitem>
 847                         </varlistentry>
 848
 849                         <varlistentry>
 850                                 <term><option>--verify-key=</option></term>
 851
 852                                 <listitem><para>Specifies the FSS
 853                                 verification key to use for the
 854                                 <option>--verify</option>
 855                                 operation.</para></listitem>
 856                         </varlistentry>
 857
 858                 </variablelist>
 859         </refsect1>
 860
 861         <refsect1>
 862                 <title>Exit status</title>
 863
 864                 <para>On success, 0 is returned; otherwise, a non-zero
 865                 failure code is returned.</para>
 866         </refsect1>
 867
 868         <refsect1>
 869                 <title>Environment</title>
 870
 871                 <variablelist class='environment-variables'>
 872                         <varlistentry>
 873                                 <term><varname>$SYSTEMD_PAGER</varname></term>
 874                                 <listitem><para>Pager to use when
 875                                 <option>--no-pager</option> is not given;
 876                                 overrides <varname>$PAGER</varname>.  Setting
 877                                 this to an empty string or the value
 878                                 <literal>cat</literal> is equivalent to passing
 879                                 <option>--no-pager</option>.</para></listitem>
 880                         </varlistentry>
 881                 </variablelist>
 882         </refsect1>
 883
 884         <refsect1>
 885                 <title>Examples</title>
 886
 887                 <para>Without arguments, all collected logs are shown
 888                 unfiltered:</para>
 889
 890                 <programlisting>journalctl</programlisting>
 891
 892                 <para>With one match specified, all entries with a field matching the expression are shown:</para>
 893
 894                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
 895
 896                 <para>If two different fields are matched, only entries matching both expressions at the same time are shown:</para>
 897
 898                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
 899
 900                 <para>If two matches refer to the same field, all entries matching either expression are shown:</para>
 901
 902                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
 903
 904                 <para>If the separator <literal>+</literal> is used,
 905                 two expressions may be combined in a logical OR. The
 906                 following will show all messages from the Avahi
 907                 service process with the PID 28097 plus all messages
 908                 from the D-Bus service (from any of its
 909                 processes):</para>
 910
 911                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
 912
 913                 <para>Show all logs generated by the D-Bus executable:</para>
 914
 915                 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
 916
 917                 <para>Show all logs of the kernel device node <filename noindex='true'>/dev/sda</filename>:</para>
 918
 919                 <programlisting>journalctl /dev/sda</programlisting>
 920
 921                 <para>Show all kernel logs from previous boot:</para>
 922
 923                 <programlisting>journalctl -k -b -1</programlisting>
 924
 925         </refsect1>
 926
 927         <refsect1>
 928                 <title>See Also</title>
 929                 <para>
 930                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 931                         <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 932                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 933                         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 934                         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 935                 </para>
 936         </refsect1>
 937
 938 </refentry>