man/journalctl.xml

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   8
   9   <refentry id="journalctl"
  10             xmlns:xi="http://www.w3.org/2001/XInclude">
  11
  12     <refentryinfo>
  13       <title>journalctl</title>
  14       <productname>systemd</productname>
  15     </refentryinfo>
  16
  17     <refmeta>
  18       <refentrytitle>journalctl</refentrytitle>
  19       <manvolnum>1</manvolnum>
  20     </refmeta>
  21
  22     <refnamediv>
  23       <refname>journalctl</refname>
  24       <refpurpose>Query the systemd journal</refpurpose>
  25     </refnamediv>
  26
  27     <refsynopsisdiv>
  28       <cmdsynopsis>
  29         <command>journalctl</command>
  30         <arg choice="opt" rep="repeat">OPTIONS</arg>
  31         <arg choice="opt" rep="repeat">MATCHES</arg>
  32       </cmdsynopsis>
  33     </refsynopsisdiv>
  34
  35     <refsect1>
  36       <title>Description</title>
  37
  38       <para><command>journalctl</command> may be used to query the
  39       contents of the
  40       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  41       journal as written by
  42       <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
  43
  44       <para>If called without parameters, it will show the full
  45       contents of the journal, starting with the oldest entry
  46       collected.</para>
  47
  48       <para>If one or more match arguments are passed, the output is
  49       filtered accordingly. A match is in the format
  50       <literal>FIELD=VALUE</literal>,
  51       e.g. <literal>_SYSTEMD_UNIT=httpd.service</literal>, referring
  52       to the components of a structured journal entry. See
  53       <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
  54       for a list of well-known fields. If multiple matches are
  55       specified matching different fields, the log entries are
  56       filtered by both, i.e. the resulting output will show only
  57       entries matching all the specified matches of this kind. If two
  58       matches apply to the same field, then they are automatically
  59       matched as alternatives, i.e. the resulting output will show
  60       entries matching any of the specified matches for the same
  61       field. Finally, the character <literal>+</literal> may appear
  62       as a separate word between other terms on the command line. This
  63       causes all matches before and after to be combined in a
  64       disjunction (i.e. logical OR).</para>
  65
  66       <para>It is also possible to filter the entries by specifying an
  67       absolute file path as an argument. The file path may be a file or
  68       a symbolic link and the file must exist at the time of the query. If a
  69       file path refers to an executable binary, an <literal>_EXE=</literal>
  70       match for the canonicalized binary path is added to the query. If a
  71       file path refers to an executable script, a <literal>_COMM=</literal>
  72       match for the script name is added to the query. If a file path
  73       refers to a device node, <literal>_KERNEL_DEVICE=</literal> matches for
  74       the kernel name of the device and for each of its ancestor devices is
  75       added to the query. Symbolic links are dereferenced, kernel names are
  76       synthesized, and parent devices are identified from the environment at
  77       the time of the query. In general, a device node is the best proxy for
  78       an actual device, as log entries do not usually contain fields that
  79       identify an actual device. For the resulting log entries to be correct
  80       for the actual device, the relevant parts of the environment at the time
  81       the entry was logged, in particular the actual device corresponding to
  82       the device node, must have been the same as those at the time of the
  83       query. Because device nodes generally change their corresponding devices
  84       across reboots, specifying a device node path causes the resulting
  85       entries to be restricted to those from the current boot.</para>
  86
  87       <para>Additional constraints may be added using options
  88       <option>--boot</option>, <option>--unit=</option>, etc., to
  89       further limit what entries will be shown (logical AND).</para>
  90
  91       <para>Output is interleaved from all accessible journal files,
  92       whether they are rotated or currently being written, and
  93       regardless of whether they belong to the system itself or are
  94       accessible user journals.</para>
  95
  96       <para>The set of journal files which will be used can be
  97       modified using the <option>--user</option>,
  98       <option>--system</option>, <option>--directory</option>, and
  99       <option>--file</option> options, see below.</para>
 100
 101       <para>All users are granted access to their private per-user
 102       journals. However, by default, only root and users who are
 103       members of a few special groups are granted access to the system
 104       journal and the journals of other users. Members of the groups
 105       <literal>systemd-journal</literal>, <literal>adm</literal>, and
 106       <literal>wheel</literal> can read all journal files. Note
 107       that the two latter groups traditionally have additional
 108       privileges specified by the distribution. Members of the
 109       <literal>wheel</literal> group can often perform administrative
 110       tasks.</para>
 111
 112       <para>The output is paged through <command>less</command> by
 113       default, and long lines are "truncated" to screen width. The
 114       hidden part can be viewed by using the left-arrow and
 115       right-arrow keys. Paging can be disabled; see the
 116       <option>--no-pager</option> option and the "Environment" section
 117       below.</para>
 118
 119       <para>When outputting to a tty, lines are colored according to
 120       priority: lines of level ERROR and higher are colored red; lines
 121       of level NOTICE and higher are highlighted; lines of level DEBUG
 122       are colored lighter grey; other lines are displayed normally.</para>
 123     </refsect1>
 124
 125     <refsect1>
 126       <title>Options</title>
 127
 128       <para>The following options are understood:</para>
 129
 130       <variablelist>
 131         <varlistentry>
 132           <term><option>--no-full</option></term>
 133           <term><option>--full</option></term>
 134           <term><option>-l</option></term>
 135
 136           <listitem><para>Ellipsize fields when they do not fit in
 137           available columns.  The default is to show full fields,
 138           allowing them to wrap or be truncated by the pager, if one
 139           is used.</para>
 140
 141           <para>The old options
 142           <option>-l</option>/<option>--full</option> are not useful
 143           anymore, except to undo <option>--no-full</option>.</para>
 144           </listitem>
 145         </varlistentry>
 146
 147         <varlistentry>
 148           <term><option>-a</option></term>
 149           <term><option>--all</option></term>
 150
 151           <listitem><para>Show all fields in full, even if they include unprintable characters or are very long. By
 152           default, fields with unprintable characters are abbreviated as "blob data". (Note that the pager may escape
 153           unprintable characters again.)</para></listitem>
 154         </varlistentry>
 155
 156         <varlistentry>
 157           <term><option>-f</option></term>
 158           <term><option>--follow</option></term>
 159
 160           <listitem><para>Show only the most recent journal entries,
 161           and continuously print new entries as they are appended to
 162           the journal.</para></listitem>
 163         </varlistentry>
 164
 165         <varlistentry>
 166           <term><option>-e</option></term>
 167           <term><option>--pager-end</option></term>
 168
 169           <listitem><para>Immediately jump to the end of the journal
 170           inside the implied pager tool. This implies
 171           <option>-n1000</option> to guarantee that the pager will not
 172           buffer logs of unbounded size. This may be overridden with
 173           an explicit <option>-n</option> with some other numeric
 174           value, while <option>-nall</option> will disable this cap.
 175           Note that this option is only supported for the
 176           <citerefentry project='man-pages'><refentrytitle>less</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 177           pager.</para></listitem>
 178         </varlistentry>
 179
 180         <varlistentry>
 181           <term><option>-n</option></term>
 182           <term><option>--lines=</option></term>
 183
 184           <listitem><para>Show the most recent journal events and
 185           limit the number of events shown. If
 186           <option>--follow</option> is used, this option is
 187           implied. The argument is a positive integer or
 188           <literal>all</literal> to disable line limiting. The default
 189           value is 10 if no argument is given.</para></listitem>
 190         </varlistentry>
 191
 192         <varlistentry>
 193           <term><option>--no-tail</option></term>
 194
 195           <listitem><para>Show all stored output lines, even in follow
 196           mode. Undoes the effect of <option>--lines=</option>.
 197           </para></listitem>
 198         </varlistentry>
 199
 200         <varlistentry>
 201           <term><option>-r</option></term>
 202           <term><option>--reverse</option></term>
 203
 204           <listitem><para>Reverse output so that the newest entries
 205           are displayed first.</para></listitem>
 206         </varlistentry>
 207
 208         <varlistentry>
 209           <term><option>-o</option></term>
 210           <term><option>--output=</option></term>
 211
 212           <listitem><para>Controls the formatting of the journal
 213           entries that are shown. Takes one of the following
 214           options:</para>
 215           <variablelist>
 216             <varlistentry>
 217               <term>
 218                 <option>short</option>
 219               </term>
 220               <listitem>
 221                 <para>is the default and generates an output that is
 222                 mostly identical to the formatting of classic syslog
 223                 files, showing one line per journal entry.</para>
 224               </listitem>
 225             </varlistentry>
 226
 227             <varlistentry>
 228               <term>
 229                 <option>short-full</option>
 230               </term>
 231               <listitem>
 232                 <para>is very similar, but shows timestamps in the format the <option>--since=</option> and
 233                 <option>--until=</option> options accept. Unlike the timestamp information shown in
 234                 <option>short</option> output mode this mode includes weekday, year and timezone information in the
 235                 output, and is locale-independent.</para>
 236               </listitem>
 237             </varlistentry>
 238
 239             <varlistentry>
 240               <term>
 241                 <option>short-iso</option>
 242               </term>
 243               <listitem>
 244                 <para>is very similar, but shows ISO 8601 wallclock
 245                 timestamps.</para>
 246               </listitem>
 247             </varlistentry>
 248
 249             <varlistentry>
 250               <term>
 251                 <option>short-iso-precise</option>
 252               </term>
 253               <listitem>
 254                 <para>as for <option>short-iso</option> but includes full
 255                 microsecond precision.</para>
 256               </listitem>
 257             </varlistentry>
 258
 259             <varlistentry>
 260               <term>
 261                 <option>short-precise</option>
 262               </term>
 263               <listitem>
 264                 <para>is very similar, but shows classic syslog timestamps
 265                 with full microsecond precision.</para>
 266               </listitem>
 267             </varlistentry>
 268
 269             <varlistentry>
 270               <term>
 271                 <option>short-monotonic</option>
 272               </term>
 273               <listitem>
 274                 <para>is very similar, but shows monotonic timestamps
 275                 instead of wallclock timestamps.</para>
 276               </listitem>
 277             </varlistentry>
 278
 279             <varlistentry>
 280               <term>
 281                 <option>short-unix</option>
 282               </term>
 283               <listitem>
 284                 <para>is very similar, but shows seconds passed since January 1st 1970 UTC instead of wallclock
 285                 timestamps ("UNIX time"). The time is shown with microsecond accuracy.</para>
 286               </listitem>
 287             </varlistentry>
 288
 289             <varlistentry>
 290               <term>
 291                 <option>verbose</option>
 292               </term>
 293               <listitem>
 294                 <para>shows the full-structured entry items with all
 295                 fields.</para>
 296               </listitem>
 297             </varlistentry>
 298
 299             <varlistentry>
 300               <term>
 301                 <option>export</option>
 302               </term>
 303               <listitem>
 304                 <para>serializes the journal into a binary (but mostly
 305                 text-based) stream suitable for backups and network
 306                 transfer (see
 307                 <ulink url="https://www.freedesktop.org/wiki/Software/systemd/export">Journal Export Format</ulink>
 308                 for more information). To import the binary stream back
 309                 into native journald format use
 310                 <citerefentry><refentrytitle>systemd-journal-remote</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
 311               </listitem>
 312             </varlistentry>
 313
 314             <varlistentry>
 315               <term>
 316                 <option>json</option>
 317               </term>
 318               <listitem>
 319                 <para>formats entries as JSON objects, separated by newline characters (see <ulink
 320                 url="https://www.freedesktop.org/wiki/Software/systemd/json">Journal JSON Format</ulink> for more
 321                 information). Field values are generally encoded as JSON strings, with three exceptions:
 322                 <orderedlist>
 323                   <listitem><para>Fields larger than 4096 bytes are encoded as <constant>null</constant> values. (This
 324                   may be turned off by passing <option>--all</option>, but be aware that this may allocate overly long
 325                   JSON objects.) </para></listitem>
 326
 327                   <listitem><para>Journal entries permit non-unique fields within the same log entry. JSON does not allow
 328                   non-unique fields within objects. Due to this, if a non-unique field is encountered a JSON array is
 329                   used as field value, listing all field values as elements.</para></listitem>
 330
 331                   <listitem><para>Fields containing non-printable or non-UTF8 bytes are encoded as arrays containing
 332                   the raw bytes individually formatted as unsigned numbers.</para></listitem>
 333                 </orderedlist>
 334
 335                 Note that this encoding is reversible (with the exception of the size limit).</para>
 336               </listitem>
 337             </varlistentry>
 338
 339             <varlistentry>
 340               <term>
 341                 <option>json-pretty</option>
 342               </term>
 343               <listitem>
 344                 <para>formats entries as JSON data structures, but
 345                 formats them in multiple lines in order to make them
 346                 more readable by humans.</para>
 347               </listitem>
 348             </varlistentry>
 349
 350             <varlistentry>
 351               <term>
 352                 <option>json-sse</option>
 353               </term>
 354               <listitem>
 355                 <para>formats entries as JSON data structures, but wraps
 356                 them in a format suitable for
 357                 <ulink url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent Events</ulink>.
 358                 </para>
 359               </listitem>
 360             </varlistentry>
 361
 362             <varlistentry>
 363               <term>
 364                 <option>json-seq</option>
 365               </term>
 366               <listitem>
 367                 <para>formats entries as JSON data structures, but prefixes them with an ASCII Record Separator
 368                 character (0x1E) and suffixes them with an ASCII Line Feed character (0x0A), in accordance with <ulink
 369                 url="https://tools.ietf.org/html/rfc7464">JavaScript Object Notation (JSON) Text Sequences </ulink>
 370                 (<literal>application/json-seq</literal>).
 371                 </para>
 372               </listitem>
 373             </varlistentry>
 374
 375             <varlistentry>
 376               <term>
 377                 <option>cat</option>
 378               </term>
 379               <listitem>
 380                 <para>generates a very terse output, only showing the
 381                 actual message of each journal entry with no metadata,
 382                 not even a timestamp.</para>
 383               </listitem>
 384             </varlistentry>
 385
 386             <varlistentry>
 387               <term>
 388                 <option>with-unit</option>
 389               </term>
 390               <listitem>
 391                 <para>similar to short-full, but prefixes the unit and
 392                 user unit names instead of the traditional syslog
 393                 identifier. Useful when using templated instances, as it
 394                 will include the arguments in the unit names.</para>
 395               </listitem>
 396             </varlistentry>
 397           </variablelist>
 398         </listitem>
 399       </varlistentry>
 400
 401       <varlistentry>
 402         <term><option>--output-fields=</option></term>
 403
 404         <listitem><para>A comma separated list of the fields which should be included in the output. This only has an
 405         effect for the output modes which would normally show all fields (<option>verbose</option>,
 406         <option>export</option>, <option>json</option>, <option>json-pretty</option>, <option>json-sse</option> and
 407         <option>json-seq</option>). The <literal>__CURSOR</literal>, <literal>__REALTIME_TIMESTAMP</literal>,
 408         <literal>__MONOTONIC_TIMESTAMP</literal>, and <literal>_BOOT_ID</literal> fields are always
 409         printed.</para></listitem>
 410       </varlistentry>
 411
 412       <varlistentry>
 413         <term><option>--utc</option></term>
 414
 415         <listitem><para>Express time in Coordinated Universal Time
 416         (UTC).</para></listitem>
 417       </varlistentry>
 418
 419       <varlistentry>
 420         <term><option>--no-hostname</option></term>
 421
 422         <listitem><para>Don't show the hostname field of log messages originating from the local host. This switch only
 423         has an effect on the <option>short</option> family of output modes (see above).</para></listitem>
 424       </varlistentry>
 425
 426       <varlistentry>
 427         <term><option>-x</option></term>
 428         <term><option>--catalog</option></term>
 429
 430         <listitem><para>Augment log lines with explanation texts from
 431         the message catalog. This will add explanatory help texts to
 432         log messages in the output where this is available. These
 433         short help texts will explain the context of an error or log
 434         event, possible solutions, as well as pointers to support
 435         forums, developer documentation, and any other relevant
 436         manuals. Note that help texts are not available for all
 437         messages, but only for selected ones. For more information on
 438         the message catalog, please refer to the
 439         <ulink url="https://www.freedesktop.org/wiki/Software/systemd/catalog">Message Catalog Developer Documentation</ulink>.</para>
 440
 441         <para>Note: when attaching <command>journalctl</command>
 442         output to bug reports, please do <emphasis>not</emphasis> use
 443         <option>-x</option>.</para>
 444         </listitem>
 445       </varlistentry>
 446
 447       <varlistentry>
 448         <term><option>-q</option></term>
 449         <term><option>--quiet</option></term>
 450
 451         <listitem><para>Suppresses all informational messages
 452         (i.e. "-- Logs begin at …", "-- Reboot --"),
 453         any warning messages regarding
 454         inaccessible system journals when run as a normal
 455         user.</para></listitem>
 456       </varlistentry>
 457
 458       <varlistentry>
 459         <term><option>-m</option></term>
 460         <term><option>--merge</option></term>
 461
 462         <listitem><para>Show entries interleaved from all available
 463         journals, including remote ones.</para></listitem>
 464       </varlistentry>
 465
 466       <varlistentry>
 467         <term><option>-b <optional><replaceable>ID</replaceable></optional><optional><replaceable>±offset</replaceable></optional></option></term>
 468         <term><option>--boot=<optional><replaceable>ID</replaceable></optional><optional><replaceable>±offset</replaceable></optional></option></term>
 469
 470         <listitem><para>Show messages from a specific boot. This will
 471         add a match for <literal>_BOOT_ID=</literal>.</para>
 472
 473         <para>The argument may be empty, in which case logs for the
 474         current boot will be shown.</para>
 475
 476         <para>If the boot ID is omitted, a positive
 477         <replaceable>offset</replaceable> will look up the boots
 478         starting from the beginning of the journal, and an
 479         equal-or-less-than zero <replaceable>offset</replaceable> will
 480         look up boots starting from the end of the journal. Thus,
 481         <constant>1</constant> means the first boot found in the
 482         journal in chronological order, <constant>2</constant> the
 483         second and so on; while <constant>-0</constant> is the last
 484         boot, <constant>-1</constant> the boot before last, and so
 485         on. An empty <replaceable>offset</replaceable> is equivalent
 486         to specifying <constant>-0</constant>, except when the current
 487         boot is not the last boot (e.g. because
 488         <option>--directory</option> was specified to look at logs
 489         from a different machine).</para>
 490
 491         <para>If the 32-character <replaceable>ID</replaceable> is
 492         specified, it may optionally be followed by
 493         <replaceable>offset</replaceable> which identifies the boot
 494         relative to the one given by boot
 495         <replaceable>ID</replaceable>. Negative values mean earlier
 496         boots and positive values mean later boots. If
 497         <replaceable>offset</replaceable> is not specified, a value of
 498         zero is assumed, and the logs for the boot given by
 499         <replaceable>ID</replaceable> are shown.</para>
 500         </listitem>
 501       </varlistentry>
 502
 503       <varlistentry>
 504         <term><option>--list-boots</option></term>
 505
 506         <listitem><para>Show a tabular list of boot numbers (relative to
 507         the current boot), their IDs, and the timestamps of the first
 508         and last message pertaining to the boot.</para></listitem>
 509       </varlistentry>
 510
 511       <varlistentry>
 512         <term><option>-k</option></term>
 513         <term><option>--dmesg</option></term>
 514
 515         <listitem><para>Show only kernel messages. This implies
 516         <option>-b</option> and adds the match
 517         <literal>_TRANSPORT=kernel</literal>.</para></listitem>
 518       </varlistentry>
 519
 520       <varlistentry>
 521         <term><option>-t</option></term>
 522         <term><option>--identifier=<replaceable>SYSLOG_IDENTIFIER</replaceable></option></term>
 523
 524         <listitem><para>Show messages for the specified syslog
 525         identifier
 526         <replaceable>SYSLOG_IDENTIFIER</replaceable>.</para>
 527
 528         <para>This parameter can be specified multiple
 529         times.</para></listitem>
 530       </varlistentry>
 531
 532       <varlistentry>
 533         <term><option>-u</option></term>
 534         <term><option>--unit=<replaceable>UNIT</replaceable>|<replaceable>PATTERN</replaceable></option></term>
 535
 536         <listitem><para>Show messages for the specified systemd unit
 537         <replaceable>UNIT</replaceable> (such as a service unit), or
 538         for any of the units matched by
 539         <replaceable>PATTERN</replaceable>.  If a pattern is
 540         specified, a list of unit names found in the journal is
 541         compared with the specified pattern and all that match are
 542         used. For each unit name, a match is added for messages from
 543         the unit
 544         (<literal>_SYSTEMD_UNIT=<replaceable>UNIT</replaceable></literal>),
 545         along with additional matches for messages from systemd and
 546         messages about coredumps for the specified unit.</para>
 547
 548         <para>This parameter can be specified multiple times.</para>
 549         </listitem>
 550       </varlistentry>
 551
 552       <varlistentry>
 553         <term><option>--user-unit=</option></term>
 554
 555         <listitem><para>Show messages for the specified user session
 556         unit. This will add a match for messages from the unit
 557         (<literal>_SYSTEMD_USER_UNIT=</literal> and
 558         <literal>_UID=</literal>) and additional matches for messages
 559         from session systemd and messages about coredumps for the
 560         specified unit.</para>
 561
 562         <para>This parameter can be specified multiple times.</para>
 563         </listitem>
 564       </varlistentry>
 565
 566       <varlistentry>
 567         <term><option>-p</option></term>
 568         <term><option>--priority=</option></term>
 569
 570         <listitem><para>Filter output by message priorities or
 571         priority ranges. Takes either a single numeric or textual log
 572         level (i.e. between 0/<literal>emerg</literal> and
 573         7/<literal>debug</literal>), or a range of numeric/text log
 574         levels in the form FROM..TO. The log levels are the usual
 575         syslog log levels as documented in
 576         <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 577         i.e. <literal>emerg</literal> (0),
 578         <literal>alert</literal> (1), <literal>crit</literal> (2),
 579         <literal>err</literal> (3), <literal>warning</literal> (4),
 580         <literal>notice</literal> (5), <literal>info</literal> (6),
 581         <literal>debug</literal> (7). If a single log level is
 582         specified, all messages with this log level or a lower (hence
 583         more important) log level are shown. If a range is specified,
 584         all messages within the range are shown, including both the
 585         start and the end value of the range. This will add
 586         <literal>PRIORITY=</literal> matches for the specified
 587         priorities.</para></listitem>
 588       </varlistentry>
 589
 590       <varlistentry>
 591         <term><option>-g</option></term>
 592         <term><option>--grep=</option></term>
 593
 594         <listitem><para>Filter output to entries where the <varname>MESSAGE=</varname>
 595         field matches the specified regular expression. PERL-compatible regular expressions
 596         are used, see
 597         <citerefentry><refentrytitle>pcre2pattern</refentrytitle><manvolnum>3</manvolnum></citerefentry>
 598         for a detailed description of the syntax.</para>
 599
 600         <para>If the pattern is all lowercase, matching is case insensitive.
 601         Otherwise, matching is case sensitive. This can be overridden with the
 602         <option>--case-sensitive</option> option, see below.</para>
 603         </listitem>
 604       </varlistentry>
 605
 606       <varlistentry>
 607         <term><option>--case-sensitive<optional>=BOOLEAN</optional></option></term>
 608
 609         <listitem><para>Make pattern matching case sensitive or case insenstive.</para>
 610         </listitem>
 611       </varlistentry>
 612
 613       <varlistentry>
 614         <term><option>-c</option></term>
 615         <term><option>--cursor=</option></term>
 616
 617         <listitem><para>Start showing entries from the location in the
 618         journal specified by the passed cursor.</para></listitem>
 619       </varlistentry>
 620
 621       <varlistentry>
 622         <term><option>--after-cursor=</option></term>
 623
 624         <listitem><para>Start showing entries from the location in the
 625         journal <emphasis>after</emphasis> the location specified by
 626         the passed cursor.  The cursor is shown when the
 627         <option>--show-cursor</option> option is used.</para>
 628         </listitem>
 629       </varlistentry>
 630
 631       <varlistentry>
 632         <term><option>--show-cursor</option></term>
 633
 634         <listitem><para>The cursor is shown after the last entry after
 635         two dashes:</para>
 636         <programlisting>-- cursor: s=0639…</programlisting>
 637         <para>The format of the cursor is private
 638         and subject to change.</para></listitem>
 639       </varlistentry>
 640
 641       <varlistentry>
 642         <term><option>-S</option></term>
 643         <term><option>--since=</option></term>
 644         <term><option>-U</option></term>
 645         <term><option>--until=</option></term>
 646
 647         <listitem><para>Start showing entries on or newer than the specified date, or on or older than the specified
 648         date, respectively. Date specifications should be of the format <literal>2012-10-30 18:17:16</literal>.  If the
 649         time part is omitted, <literal>00:00:00</literal> is assumed.  If only the seconds component is omitted,
 650         <literal>:00</literal> is assumed. If the date component is omitted, the current day is assumed. Alternatively
 651         the strings <literal>yesterday</literal>, <literal>today</literal>, <literal>tomorrow</literal> are understood,
 652         which refer to 00:00:00 of the day before the current day, the current day, or the day after the current day,
 653         respectively. <literal>now</literal> refers to the current time. Finally, relative times may be specified,
 654         prefixed with <literal>-</literal> or <literal>+</literal>, referring to times before or after the current
 655         time, respectively. For complete time and date specification, see
 656         <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>. Note that
 657         <option>--output=short-full</option> prints timestamps that follow precisely this format.
 658         </para>
 659         </listitem>
 660       </varlistentry>
 661
 662       <varlistentry>
 663         <term><option>-F</option></term>
 664         <term><option>--field=</option></term>
 665
 666         <listitem><para>Print all possible data values the specified
 667         field can take in all entries of the journal.</para></listitem>
 668       </varlistentry>
 669
 670       <varlistentry>
 671         <term><option>-N</option></term>
 672         <term><option>--fields</option></term>
 673
 674         <listitem><para>Print all field names currently used in all entries of the journal.</para></listitem>
 675       </varlistentry>
 676
 677       <varlistentry>
 678         <term><option>--system</option></term>
 679         <term><option>--user</option></term>
 680
 681         <listitem><para>Show messages from system services and the
 682         kernel (with <option>--system</option>). Show messages from
 683         service of current user (with <option>--user</option>).  If
 684         neither is specified, show all messages that the user can see.
 685         </para></listitem>
 686       </varlistentry>
 687
 688       <varlistentry>
 689         <term><option>-M</option></term>
 690         <term><option>--machine=</option></term>
 691
 692         <listitem><para>Show messages from a running, local
 693         container. Specify a container name to connect to.</para>
 694         </listitem>
 695       </varlistentry>
 696
 697       <varlistentry>
 698         <term><option>-D <replaceable>DIR</replaceable></option></term>
 699         <term><option>--directory=<replaceable>DIR</replaceable></option></term>
 700
 701         <listitem><para>Takes a directory path as argument. If
 702         specified, journalctl will operate on the specified journal
 703         directory <replaceable>DIR</replaceable> instead of the
 704         default runtime and system journal paths.</para></listitem>
 705       </varlistentry>
 706
 707       <varlistentry>
 708         <term><option>--file=<replaceable>GLOB</replaceable></option></term>
 709
 710         <listitem><para>Takes a file glob as an argument. If
 711         specified, journalctl will operate on the specified journal
 712         files matching <replaceable>GLOB</replaceable> instead of the
 713         default runtime and system journal paths. May be specified
 714         multiple times, in which case files will be suitably
 715         interleaved.</para></listitem>
 716       </varlistentry>
 717
 718       <varlistentry>
 719         <term><option>--root=<replaceable>ROOT</replaceable></option></term>
 720
 721         <listitem><para>Takes a directory path as an argument. If
 722         specified, journalctl will operate on journal directories and catalog file hierarchy
 723         underneath the specified directory instead of the root
 724         directory (e.g. <option>--update-catalog</option> will create
 725         <filename><replaceable>ROOT</replaceable>/var/lib/systemd/catalog/database</filename>,
 726         and journal files under <filename><replaceable>ROOT</replaceable>/run/journal</filename>
 727         or <filename><replaceable>ROOT</replaceable>/var/log/journal</filename> will be displayed).
 728         </para></listitem>
 729       </varlistentry>
 730
 731       <varlistentry>
 732         <term><option>--header</option></term>
 733
 734         <listitem><para>Instead of showing journal contents, show
 735         internal header information of the journal fields
 736         accessed.</para></listitem>
 737       </varlistentry>
 738
 739       <varlistentry>
 740         <term><option>--disk-usage</option></term>
 741
 742         <listitem><para>Shows the current disk usage of all journal
 743         files. This shows the sum of the disk usage of all archived
 744         and active journal files.</para></listitem>
 745       </varlistentry>
 746
 747       <varlistentry>
 748         <term><option>--vacuum-size=</option></term>
 749         <term><option>--vacuum-time=</option></term>
 750         <term><option>--vacuum-files=</option></term>
 751
 752         <listitem><para>Removes the oldest archived journal files until the disk space they use falls below the
 753         specified size (specified with the usual <literal>K</literal>, <literal>M</literal>, <literal>G</literal> and
 754         <literal>T</literal> suffixes), or all archived journal files contain no data older than the specified timespan
 755         (specified with the usual <literal>s</literal>, <literal>m</literal>, <literal>h</literal>,
 756         <literal>days</literal>, <literal>months</literal>, <literal>weeks</literal> and <literal>years</literal>
 757         suffixes), or no more than the specified number of separate journal files remain. Note that running
 758         <option>--vacuum-size=</option> has only an indirect effect on the output shown by
 759         <option>--disk-usage</option>, as the latter includes active journal files, while the vacuuming operation only
 760         operates on archived journal files. Similarly, <option>--vacuum-files=</option> might not actually reduce the
 761         number of journal files to below the specified number, as it will not remove active journal
 762         files.</para>
 763
 764         <para><option>--vacuum-size=</option>, <option>--vacuum-time=</option> and <option>--vacuum-files=</option>
 765         may be combined in a single invocation to enforce any combination of a size, a time and a number of files limit
 766         on the archived journal files. Specifying any of these three parameters as zero is equivalent to not enforcing
 767         the specific limit, and is thus redundant.</para>
 768
 769         <para>These three switches may also be combined with <option>--rotate</option> into one command. If so, all
 770         active files are rotated first, and the requested vacuuming operation is executed right after. The rotation has
 771         the effect that all currently active files are archived (and potentially new, empty journal files opened as
 772         replacement), and hence the vacuuming operation has the greatest effect as it can take all log data written so
 773         far into account.</para></listitem>
 774       </varlistentry>
 775
 776       <varlistentry>
 777         <term><option>--list-catalog
 778         <optional><replaceable>128-bit-ID…</replaceable></optional>
 779         </option></term>
 780
 781         <listitem><para>List the contents of the message catalog as a
 782         table of message IDs, plus their short description strings.
 783         </para>
 784
 785         <para>If any <replaceable>128-bit-ID</replaceable>s are
 786         specified, only those entries are shown.</para>
 787         </listitem>
 788       </varlistentry>
 789
 790       <varlistentry>
 791         <term><option>--dump-catalog
 792         <optional><replaceable>128-bit-ID…</replaceable></optional>
 793         </option></term>
 794
 795         <listitem><para>Show the contents of the message catalog, with
 796         entries separated by a line consisting of two dashes and the
 797         ID (the format is the same as <filename>.catalog</filename>
 798         files).</para>
 799
 800         <para>If any <replaceable>128-bit-ID</replaceable>s are
 801         specified, only those entries are shown.</para>
 802         </listitem>
 803       </varlistentry>
 804
 805       <varlistentry>
 806         <term><option>--update-catalog</option></term>
 807
 808         <listitem><para>Update the message catalog index. This command
 809         needs to be executed each time new catalog files are
 810         installed, removed, or updated to rebuild the binary catalog
 811         index.</para></listitem>
 812       </varlistentry>
 813
 814       <varlistentry>
 815         <term><option>--setup-keys</option></term>
 816
 817         <listitem><para>Instead of showing journal contents, generate
 818         a new key pair for Forward Secure Sealing (FSS). This will
 819         generate a sealing key and a verification key. The sealing key
 820         is stored in the journal data directory and shall remain on
 821         the host. The verification key should be stored
 822         externally. Refer to the <option>Seal=</option> option in
 823         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 824         for information on Forward Secure Sealing and for a link to a
 825         refereed scholarly paper detailing the cryptographic theory it
 826         is based on.</para></listitem>
 827       </varlistentry>
 828
 829       <varlistentry>
 830         <term><option>--force</option></term>
 831
 832         <listitem><para>When <option>--setup-keys</option> is passed
 833         and Forward Secure Sealing (FSS) has already been configured,
 834         recreate FSS keys.</para></listitem>
 835       </varlistentry>
 836
 837       <varlistentry>
 838         <term><option>--interval=</option></term>
 839
 840         <listitem><para>Specifies the change interval for the sealing
 841         key when generating an FSS key pair with
 842         <option>--setup-keys</option>. Shorter intervals increase CPU
 843         consumption but shorten the time range of undetectable journal
 844         alterations. Defaults to 15min.</para></listitem>
 845       </varlistentry>
 846
 847       <varlistentry>
 848         <term><option>--verify</option></term>
 849
 850         <listitem><para>Check the journal file for internal
 851         consistency. If the file has been generated with FSS enabled and
 852         the FSS verification key has been specified with
 853         <option>--verify-key=</option>, authenticity of the journal file
 854         is verified.</para></listitem>
 855       </varlistentry>
 856
 857       <varlistentry>
 858         <term><option>--verify-key=</option></term>
 859
 860         <listitem><para>Specifies the FSS verification key to use for
 861         the <option>--verify</option> operation.</para></listitem>
 862       </varlistentry>
 863
 864       <varlistentry>
 865         <term><option>--sync</option></term>
 866
 867         <listitem><para>Asks the journal daemon to write all yet
 868         unwritten journal data to the backing file system and
 869         synchronize all journals. This call does not return until the
 870         synchronization operation is complete. This command guarantees
 871         that any log messages written before its invocation are safely
 872         stored on disk at the time it returns.</para></listitem>
 873       </varlistentry>
 874
 875       <varlistentry>
 876         <term><option>--flush</option></term>
 877
 878         <listitem><para>Asks the journal daemon to flush any log data
 879         stored in <filename>/run/log/journal</filename> into
 880         <filename>/var/log/journal</filename>, if persistent storage
 881         is enabled. This call does not return until the operation is
 882         complete. Note that this call is idempotent: the data is only
 883         flushed from <filename>/run/log/journal</filename> into
 884         <filename>/var/log/journal</filename> once during system
 885         runtime, and this command exits cleanly without executing any
 886         operation if this has already happened. This command
 887         effectively guarantees that all data is flushed to
 888         <filename>/var/log/journal</filename> at the time it
 889         returns.</para></listitem>
 890       </varlistentry>
 891
 892       <varlistentry>
 893         <term><option>--rotate</option></term>
 894
 895         <listitem><para>Asks the journal daemon to rotate journal files. This call does not return until the rotation
 896         operation is complete. Journal file rotation has the effect that all currently active journal files are marked
 897         as archived and renamed, so that they are never written to in future. New (empty) journal files are then
 898         created in their place. This operation may be combined with <option>--vacuum-size=</option>,
 899         <option>--vacuum-time=</option> and <option>--vacuum-file=</option> into a single command, see
 900         above.</para></listitem>
 901       </varlistentry>
 902
 903       <xi:include href="standard-options.xml" xpointer="help" />
 904       <xi:include href="standard-options.xml" xpointer="version" />
 905       <xi:include href="standard-options.xml" xpointer="no-pager" />
 906     </variablelist>
 907   </refsect1>
 908
 909   <refsect1>
 910     <title>Exit status</title>
 911
 912     <para>On success, 0 is returned; otherwise, a non-zero failure
 913     code is returned.</para>
 914   </refsect1>
 915
 916   <xi:include href="less-variables.xml" />
 917
 918   <refsect1>
 919     <title>Examples</title>
 920
 921     <para>Without arguments, all collected logs are shown
 922     unfiltered:</para>
 923
 924     <programlisting>journalctl</programlisting>
 925
 926     <para>With one match specified, all entries with a field matching
 927     the expression are shown:</para>
 928
 929     <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service
 930 journalctl _SYSTEMD_CGROUP=/user.slice/user-42.slice/session-c1.scope</programlisting>
 931
 932     <para>If two different fields are matched, only entries matching
 933     both expressions at the same time are shown:</para>
 934
 935     <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
 936
 937     <para>If two matches refer to the same field, all entries matching
 938     either expression are shown:</para>
 939
 940     <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
 941
 942     <para>If the separator <literal>+</literal> is used, two
 943     expressions may be combined in a logical OR. The following will
 944     show all messages from the Avahi service process with the PID
 945     28097 plus all messages from the D-Bus service (from any of its
 946     processes):</para>
 947
 948     <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
 949
 950     <para>To show all fields emitted <emphasis>by</emphasis> a unit and <emphasis>about</emphasis>
 951     the unit, option <option>-u</option>/<option>--unit=</option> should be used.
 952     <command>journalctl -u <replaceable>name</replaceable></command>
 953     expands to a complex filter similar to
 954     <programlisting>_SYSTEMD_UNIT=<replaceable>name</replaceable>.service
 955   + UNIT=<replaceable>name</replaceable>.service _PID=1
 956   + OBJECT_SYSTEMD_UNIT=<replaceable>name</replaceable>.service _UID=0
 957   + COREDUMP_UNIT=<replaceable>name</replaceable>.service _UID=0 MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1
 958     </programlisting>
 959     (see <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 960     for an explanation of those patterns).
 961     </para>
 962
 963     <para>Show all logs generated by the D-Bus executable:</para>
 964
 965     <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
 966
 967     <para>Show all kernel logs from previous boot:</para>
 968
 969     <programlisting>journalctl -k -b -1</programlisting>
 970
 971     <para>Show a live log display from a system service
 972     <filename>apache.service</filename>:</para>
 973
 974     <programlisting>journalctl -f -u apache</programlisting>
 975
 976   </refsect1>
 977
 978   <refsect1>
 979     <title>See Also</title>
 980     <para>
 981       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 982       <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 983       <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 984       <citerefentry><refentrytitle>coredumpctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 985       <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 986       <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
 987       <citerefentry><refentrytitle>systemd.time</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 988       <citerefentry><refentrytitle>systemd-journal-remote.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 989       <citerefentry><refentrytitle>systemd-journal-upload.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
 990     </para>
 991   </refsect1>
 992 </refentry>