man/journalctl.xml

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   8   Copyright 2012 Lennart Poettering
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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 <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt" rep="repeat">MATCHES</arg></command>
  53                 </cmdsynopsis>
  54         </refsynopsisdiv>
  55
  56         <refsect1>
  57                 <title>Description</title>
  58
  59                 <para><command>journalctl</command> may be used to
  60                 query the contents of the
  61                 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  62                 journal as written by
  63                 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
  64
  65                 <para>If called without parameter it will show the full
  66                 contents of the journal, starting with the oldest
  67                 entry collected.</para>
  68
  69                 <para>If one or more match arguments are passed the
  70                 output is filtered accordingly. A match is in the
  71                 format <literal>FIELD=VALUE</literal>,
  72                 e.g. <literal>_SYSTEMD_UNIT=httpd.service</literal>,
  73                 referring to the components of a structured journal
  74                 entry. See
  75                 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
  76                 for a list of well-known fields. If multiple matches
  77                 are specified matching different fields the log
  78                 entries are filtered by both, i.e. the resulting output
  79                 will show only entries matching all the specified
  80                 matches of this kind. If two matches apply to the same
  81                 field, then they are automatically matched as
  82                 alternatives, i.e. the resulting output will show
  83                 entries matching any of the specified matches for the
  84                 same field. Finally, if the character
  85                 "<literal>+</literal>" appears as separate word on the
  86                 command line all matches before and after are combined
  87                 in a disjunction (i.e. logical OR).</para>
  88
  89                 <para>As shortcuts for a few types of field/value
  90                 matches file paths may be specified. If a file path
  91                 refers to an executable file, this is equivalent to an
  92                 <literal>_EXE=</literal> match for the canonicalized
  93                 binary path. Similar, if a path refers to a device
  94                 node, this is equivalent to a
  95                 <literal>_KERNEL_DEVICE=</literal> match for the
  96                 device.</para>
  97
  98                 <para>Output is interleaved from all accessible
  99                 journal files, whether they are rotated or currently
 100                 being written, and regardless whether they belong to the
 101                 system itself or are accessible user journals.</para>
 102
 103                 <para>All users are granted access to their private
 104                 per-user journals. However, by default only root and
 105                 users who are members of the <literal>adm</literal>
 106                 group get access to the system journal and the
 107                 journals of other users.</para>
 108         </refsect1>
 109
 110         <refsect1>
 111                 <title>Options</title>
 112
 113                 <para>The following options are understood:</para>
 114
 115                 <variablelist>
 116                         <varlistentry>
 117                                 <term><option>--help</option></term>
 118                                 <term><option>-h</option></term>
 119
 120                                 <listitem><para>Prints a short help
 121                                 text and exits.</para></listitem>
 122                         </varlistentry>
 123
 124                         <varlistentry>
 125                                 <term><option>--version</option></term>
 126
 127                                 <listitem><para>Prints a short version
 128                                 string and exits.</para></listitem>
 129                         </varlistentry>
 130
 131                         <varlistentry>
 132                                 <term><option>--no-pager</option></term>
 133
 134                                 <listitem><para>Do not pipe output into a
 135                                 pager.</para></listitem>
 136                         </varlistentry>
 137
 138                         <varlistentry>
 139                                 <term><option>--full</option></term>
 140
 141                                 <listitem><para>Show all (printable) fields in
 142                                 full.</para></listitem>
 143                         </varlistentry>
 144
 145                         <varlistentry>
 146                                 <term><option>--all</option></term>
 147                                 <term><option>-a</option></term>
 148
 149                                 <listitem><para>Show all fields in
 150                                 full, even if they include unprintable
 151                                 characters or are very
 152                                 long.</para></listitem>
 153                         </varlistentry>
 154
 155                         <varlistentry>
 156                                 <term><option>--follow</option></term>
 157                                 <term><option>-f</option></term>
 158
 159                                 <listitem><para>Show only the most recent
 160                                 journal entries, and continuously print
 161                                 new entries as they are appended to
 162                                 the journal.</para></listitem>
 163                         </varlistentry>
 164
 165                         <varlistentry>
 166                                 <term><option>--lines=</option></term>
 167                                 <term><option>-n</option></term>
 168
 169                                 <listitem><para>Show the most recent
 170                                 journal events and limit the number of
 171                                 events shown. If
 172                                 <option>--follow</option> is used,
 173                                 this option is implied. The argument,
 174                                 a positive integer, is optional, and
 175                                 defaults to 10. </para></listitem>
 176                         </varlistentry>
 177
 178                         <varlistentry>
 179                                 <term><option>--no-tail</option></term>
 180
 181                                 <listitem><para>Show all stored output
 182                                 lines, even in follow mode. Undoes the
 183                                 effect of
 184                                 <option>--lines=</option>.</para></listitem>
 185                         </varlistentry>
 186
 187                         <varlistentry>
 188                                 <term><option>--output=</option></term>
 189                                 <term><option>-o</option></term>
 190
 191                                 <listitem><para>Controls the
 192                                 formatting of the journal entries that
 193                                 are shown. Takes one of
 194                                 <literal>short</literal>,
 195                                 <literal>short-monotonic</literal>,
 196                                 <literal>verbose</literal>,
 197                                 <literal>export</literal>,
 198                                 <literal>json</literal>,
 199                                 <literal>json-pretty</literal>,
 200                                 <literal>json-sse</literal>,
 201                                 <literal>cat</literal>. <literal>short</literal>
 202                                 is the default and generates an output
 203                                 that is mostly identical to the
 204                                 formatting of classic syslog log
 205                                 files, showing one line per journal
 206                                 entry. <literal>short-monotonic</literal>
 207                                 is very similar but shows monotonic
 208                                 timestamps instead of wallclock
 209                                 timestamps. <literal>verbose</literal>
 210                                 shows the full structured entry items
 211                                 with all
 212                                 fields. <literal>export</literal>
 213                                 serializes the journal into a binary
 214                                 (but mostly text-based) stream
 215                                 suitable for backups and network
 216                                 transfer (see <ulink
 217                                 url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal
 218                                 Export Format</ulink> for more
 219                                 information). <literal>json</literal>
 220                                 formats entries as JSON data
 221                                 structures, one per
 222                                 line (see <ulink
 223                                 url="http://www.freedesktop.org/wiki/Software/systemd/json">Journal
 224                                 JSON Format</ulink> for more
 225                                 information). <literal>json-pretty</literal>
 226                                 also formats entries as JSON data
 227                                 structures, but formats them in
 228                                 multiple lines in order to make them
 229                                 more readable for
 230                                 humans. <literal>json-sse</literal>
 231                                 also formats entries as JSON data
 232                                 structures, but wraps them in a format
 233                                 suitable for <ulink
 234                                 url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent
 235                                 Events</ulink>. <literal>cat</literal>
 236                                 generates a very terse output only
 237                                 showing the actual message of each
 238                                 journal entry with no meta data, not
 239                                 even a timestamp.</para></listitem>
 240                         </varlistentry>
 241
 242                         <varlistentry>
 243                                 <term><option>--catalog</option></term>
 244                                 <term><option>-x</option></term>
 245
 246                                 <listitem><para>Augment log lines with
 247                                 explanation texts from the message
 248                                 catalog. This will add explanatory
 249                                 help texts to log messages in the
 250                                 output where this is available. These
 251                                 short help texts will explain the
 252                                 context of an error or log event,
 253                                 possible solutions, as well as
 254                                 pointers to support forums, developer
 255                                 documentation and any other relevant
 256                                 manuals. Note that help texts are not
 257                                 available for all messages, but only
 258                                 for selected ones. For more
 259                                 information on the message catalog
 260                                 please refer to the <ulink
 261                                 url="http://www.freedesktop.org/wiki/Software/systemd/catalog">Message
 262                                 Catalog Developer
 263                                 Documentation</ulink>.</para></listitem>
 264                         </varlistentry>
 265
 266                         <varlistentry>
 267                                 <term><option>--quiet</option></term>
 268                                 <term><option>-q</option></term>
 269
 270                                 <listitem><para>Suppresses any warning
 271                                 message regarding inaccessible system
 272                                 journals when run as normal
 273                                 user.</para></listitem>
 274                         </varlistentry>
 275
 276                         <varlistentry>
 277                                 <term><option>--merge</option></term>
 278                                 <term><option>-m</option></term>
 279
 280                                 <listitem><para>Show entries
 281                                 interleaved from all available
 282                                 journals, including remote
 283                                 ones.</para></listitem>
 284                         </varlistentry>
 285
 286                         <varlistentry>
 287                                 <term><option>--this-boot</option></term>
 288                                 <term><option>-b</option></term>
 289
 290                                 <listitem><para>Show data only from
 291                                 current boot. This will add a match
 292                                 for <literal>_BOOT_ID=</literal> for
 293                                 the current boot ID of the
 294                                 kernel.</para></listitem>
 295                         </varlistentry>
 296
 297                         <varlistentry>
 298                                 <term><option>--unit=</option></term>
 299                                 <term><option>-u</option></term>
 300
 301                                 <listitem><para>Show data only of the
 302                                 specified unit. This will add a match
 303                                 for <literal>_SYSTEMD_UNIT=</literal>
 304                                 for the specified
 305                                 unit.</para></listitem>
 306                         </varlistentry>
 307
 308                         <varlistentry>
 309                                 <term><option>-p</option></term>
 310                                 <term><option>--priority=</option></term>
 311
 312                                 <listitem><para>Filter output by
 313                                 message priorities or priority
 314                                 ranges. Takes either a single numeric
 315                                 or textual log level (i.e. between
 316                                 0/<literal>emerg</literal> and
 317                                 7/<literal>debug</literal>), or a
 318                                 range of numeric/text log levels in
 319                                 the form FROM..TO. The log levels are
 320                                 the usual syslog log levels as
 321                                 documented in
 322                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 323                                 i.e. <literal>emerg</literal> (0),
 324                                 <literal>alert</literal> (1),
 325                                 <literal>crit</literal> (2),
 326                                 <literal>err</literal> (3),
 327                                 <literal>warning</literal> (4),
 328                                 <literal>notice</literal> (5),
 329                                 <literal>info</literal> (6),
 330                                 <literal>debug</literal> (7). If a
 331                                 single log level is specified all
 332                                 messages with this log level or a
 333                                 lower (hence more important) log level
 334                                 are shown. If a range is specified all
 335                                 messages within the range are shown,
 336                                 including both the start and the end
 337                                 value of the range. This will add
 338                                 <literal>PRIORITY=</literal> matches
 339                                 for the specified
 340                                 priorities.</para></listitem>
 341                         </varlistentry>
 342
 343                         <varlistentry>
 344                                 <term><option>--cursor=</option></term>
 345                                 <term><option>-c</option></term>
 346
 347                                 <listitem><para>Start showing entries
 348                                 from the location in the journal
 349                                 specified by the passed
 350                                 cursor.</para></listitem>
 351                         </varlistentry>
 352
 353                         <varlistentry>
 354                                 <term><option>--since=</option></term>
 355                                 <term><option>--until=</option></term>
 356
 357                                 <listitem><para>Start showing entries
 358                                 on or newer than the specified date,
 359                                 or on or older than the specified
 360                                 date, respectively. Date specifications should be of
 361                                 the format "2012-10-30 18:17:16". If
 362                                 the time part is omitted, 00:00:00 is
 363                                 assumed. If only the seconds component
 364                                 is omitted, :00 is assumed. If the
 365                                 date component is omitted, the
 366                                 current day is assumed. Alternatively
 367                                 the strings
 368                                 <literal>yesterday</literal>,
 369                                 <literal>today</literal>,
 370                                 <literal>tomorrow</literal> are
 371                                 understood, which refer to 00:00:00 of
 372                                 the day before the current day, the
 373                                 current day, or the day after the
 374                                 current day, respectively. <literal>now</literal>
 375                                 refers to the current time. Finally,
 376                                 relative times may be specified,
 377                                 prefixed with <literal>-</literal> or
 378                                 <literal>+</literal>, referring to
 379                                 times before or after the current
 380                                 time, respectively.</para></listitem>
 381                         </varlistentry>
 382
 383                         <varlistentry>
 384                                 <term><option>--field=</option></term>
 385                                 <term><option>-F</option></term>
 386
 387                                 <listitem><para>Print all possible
 388                                 data values the specified field can
 389                                 take in all entries of the
 390                                 journal.</para></listitem>
 391                         </varlistentry>
 392
 393                         <varlistentry>
 394                                 <term><option>--directory=</option></term>
 395                                 <term><option>-D</option></term>
 396
 397                                 <listitem><para>Takes an absolute
 398                                 directory path as argument. If
 399                                 specified journalctl will operate on the
 400                                 specified journal directory instead of
 401                                 the default runtime and system journal
 402                                 paths.</para></listitem>
 403                         </varlistentry>
 404
 405                         <varlistentry>
 406                                 <term><option>--new-id128</option></term>
 407
 408                                 <listitem><para>Instead of showing
 409                                 journal contents generate a new 128
 410                                 bit ID suitable for identifying
 411                                 messages. This is intended for usage
 412                                 by developers who need a new
 413                                 identifier for a new message they
 414                                 introduce and want to make
 415                                 recognizable. Will print the new ID in
 416                                 three different formats which can be
 417                                 copied into source code or
 418                                 similar.</para></listitem>
 419                         </varlistentry>
 420
 421                         <varlistentry>
 422                                 <term><option>--header</option></term>
 423
 424                                 <listitem><para>Instead of showing
 425                                 journal contents show internal header
 426                                 information of the journal fields
 427                                 accessed.</para></listitem>
 428                         </varlistentry>
 429
 430                         <varlistentry>
 431                                 <term><option>--disk-usage</option></term>
 432
 433                                 <listitem><para>Shows the current disk
 434                                 usage of all
 435                                 journal files.</para></listitem>
 436                         </varlistentry>
 437
 438                         <varlistentry>
 439                                 <term><option>--list-catalog</option></term>
 440
 441                                 <listitem><para>List the contents of
 442                                 the message catalog, as table of
 443                                 message IDs plus their short
 444                                 description strings.</para></listitem>
 445                         </varlistentry>
 446
 447                         <varlistentry>
 448                                 <term><option>--update-catalog</option></term>
 449
 450                                 <listitem><para>Update the message
 451                                 catalog index. This command needs to
 452                                 be executed each time new catalog
 453                                 files are installed, removed or
 454                                 updated to rebuild the binary catalog
 455                                 index.</para></listitem>
 456                         </varlistentry>
 457
 458                         <varlistentry>
 459                                 <term><option>--setup-keys</option></term>
 460
 461                                 <listitem><para>Instead of showing
 462                                 journal contents generate a new key
 463                                 pair for Forward Secure Sealing
 464                                 (FSS). This will generate a sealing
 465                                 key and a verification key. The
 466                                 sealing key is stored in the journal
 467                                 data directory and shall remain on the
 468                                 host. The verification key should be
 469                                 stored externally.</para></listitem>
 470                         </varlistentry>
 471
 472                         <varlistentry>
 473                                 <term><option>--interval=</option></term>
 474
 475                                 <listitem><para>Specifies the change
 476                                 interval for the sealing key, when
 477                                 generating an FSS key pair with
 478                                 <option>--setup-keys</option>. Shorter
 479                                 intervals increase CPU consumption but
 480                                 shorten the time range of
 481                                 undetectable journal
 482                                 alterations. Defaults to
 483                                 15min.</para></listitem>
 484                         </varlistentry>
 485
 486                         <varlistentry>
 487                                 <term><option>--verify</option></term>
 488
 489                                 <listitem><para>Check the journal file
 490                                 for internal consistency. If the
 491                                 file has been generated with FSS
 492                                 enabled, and the FSS verification key
 493                                 has been specified with
 494                                 <option>--verify-key=</option>
 495                                 authenticity of the journal file is
 496                                 verified.</para></listitem>
 497                         </varlistentry>
 498
 499                         <varlistentry>
 500                                 <term><option>--verify-key=</option></term>
 501
 502                                 <listitem><para>Specifies the FSS
 503                                 verification key to use for the
 504                                 <option>--verify</option>
 505                                 operation.</para></listitem>
 506                         </varlistentry>
 507
 508                 </variablelist>
 509         </refsect1>
 510
 511         <refsect1>
 512                 <title>Exit status</title>
 513
 514                 <para>On success 0 is returned, a non-zero failure
 515                 code otherwise.</para>
 516         </refsect1>
 517
 518         <refsect1>
 519                 <title>Environment</title>
 520
 521                 <variablelist>
 522                         <varlistentry>
 523                                 <term><varname>$SYSTEMD_PAGER</varname></term>
 524                                 <listitem><para>Pager to use when
 525                                 <option>--no-pager</option> is not given;
 526                                 overrides <varname>$PAGER</varname>.  Setting
 527                                 this to an empty string or the value
 528                                 <literal>cat</literal> is equivalent to passing
 529                                 <option>--no-pager</option>.</para></listitem>
 530                         </varlistentry>
 531                 </variablelist>
 532         </refsect1>
 533
 534         <refsect1>
 535                 <title>Examples</title>
 536
 537                 <para>Without arguments all collected logs are shown
 538                 unfiltered:</para>
 539
 540                 <programlisting>journalctl</programlisting>
 541
 542                 <para>With one match specified all entries with a field matching the expression are shown:</para>
 543
 544                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
 545
 546                 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
 547
 548                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
 549
 550                 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
 551
 552                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
 553
 554                 <para>If the separator "<literal>+</literal>" is used
 555                 two expressions may be combined in a logical OR. The
 556                 following will show all messages from the Avahi
 557                 service process with the PID 28097 plus all messages
 558                 from the D-Bus service (from any of its
 559                 processes):</para>
 560
 561                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
 562
 563                 <para>Show all logs generated by the D-Bus executable:</para>
 564
 565                 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
 566
 567                 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
 568
 569                 <programlisting>journalctl /dev/sda</programlisting>
 570
 571         </refsect1>
 572
 573         <refsect1>
 574                 <title>See Also</title>
 575                 <para>
 576                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 577                         <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 578                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 579                         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 580                         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 581                 </para>
 582         </refsect1>
 583
 584 </refentry>