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 <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>-h</option></term>
 118                                 <term><option>--help</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>-a</option></term>
 147                                 <term><option>--all</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>-f</option></term>
 157                                 <term><option>--follow</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>-n</option></term>
 167                                 <term><option>--lines=</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>-r</option></term>
 189                                 <term><option>--reverse</option></term>
 190
 191                                 <listitem><para>Reverse output, so the newest
 192                                 entries are displayed first.</para></listitem>
 193                         </varlistentry>
 194
 195                         <varlistentry>
 196                                 <term><option>-o</option></term>
 197                                 <term><option>--output=</option></term>
 198
 199                                 <listitem><para>Controls the
 200                                 formatting of the journal entries that
 201                                 are shown. Takes one of
 202                                 <literal>short</literal>,
 203                                 <literal>short-monotonic</literal>,
 204                                 <literal>verbose</literal>,
 205                                 <literal>export</literal>,
 206                                 <literal>json</literal>,
 207                                 <literal>json-pretty</literal>,
 208                                 <literal>json-sse</literal>,
 209                                 <literal>cat</literal>. <literal>short</literal>
 210                                 is the default and generates an output
 211                                 that is mostly identical to the
 212                                 formatting of classic syslog log
 213                                 files, showing one line per journal
 214                                 entry. <literal>short-monotonic</literal>
 215                                 is very similar but shows monotonic
 216                                 timestamps instead of wallclock
 217                                 timestamps. <literal>verbose</literal>
 218                                 shows the full structured entry items
 219                                 with all
 220                                 fields. <literal>export</literal>
 221                                 serializes the journal into a binary
 222                                 (but mostly text-based) stream
 223                                 suitable for backups and network
 224                                 transfer (see <ulink
 225                                 url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal
 226                                 Export Format</ulink> for more
 227                                 information). <literal>json</literal>
 228                                 formats entries as JSON data
 229                                 structures, one per
 230                                 line (see <ulink
 231                                 url="http://www.freedesktop.org/wiki/Software/systemd/json">Journal
 232                                 JSON Format</ulink> for more
 233                                 information). <literal>json-pretty</literal>
 234                                 also formats entries as JSON data
 235                                 structures, but formats them in
 236                                 multiple lines in order to make them
 237                                 more readable for
 238                                 humans. <literal>json-sse</literal>
 239                                 also formats entries as JSON data
 240                                 structures, but wraps them in a format
 241                                 suitable for <ulink
 242                                 url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent
 243                                 Events</ulink>. <literal>cat</literal>
 244                                 generates a very terse output only
 245                                 showing the actual message of each
 246                                 journal entry with no meta data, not
 247                                 even a timestamp.</para></listitem>
 248                         </varlistentry>
 249
 250                         <varlistentry>
 251                                 <term><option>-x</option></term>
 252                                 <term><option>--catalog</option></term>
 253
 254                                 <listitem><para>Augment log lines with
 255                                 explanation texts from the message
 256                                 catalog. This will add explanatory
 257                                 help texts to log messages in the
 258                                 output where this is available. These
 259                                 short help texts will explain the
 260                                 context of an error or log event,
 261                                 possible solutions, as well as
 262                                 pointers to support forums, developer
 263                                 documentation and any other relevant
 264                                 manuals. Note that help texts are not
 265                                 available for all messages, but only
 266                                 for selected ones. For more
 267                                 information on the message catalog
 268                                 please refer to the <ulink
 269                                 url="http://www.freedesktop.org/wiki/Software/systemd/catalog">Message
 270                                 Catalog Developer
 271                                 Documentation</ulink>.</para></listitem>
 272                         </varlistentry>
 273
 274                         <varlistentry>
 275                                 <term><option>-q</option></term>
 276                                 <term><option>--quiet</option></term>
 277
 278                                 <listitem><para>Suppresses any warning
 279                                 message regarding inaccessible system
 280                                 journals when run as normal
 281                                 user.</para></listitem>
 282                         </varlistentry>
 283
 284                         <varlistentry>
 285                                 <term><option>-m</option></term>
 286                                 <term><option>--merge</option></term>
 287
 288                                 <listitem><para>Show entries
 289                                 interleaved from all available
 290                                 journals, including remote
 291                                 ones.</para></listitem>
 292                         </varlistentry>
 293
 294                         <varlistentry>
 295                                 <term><option>-b</option></term>
 296                                 <term><option>--this-boot</option></term>
 297
 298                                 <listitem><para>Show data only from
 299                                 current boot. This will add a match
 300                                 for <literal>_BOOT_ID=</literal> for
 301                                 the current boot ID of the
 302                                 kernel.</para></listitem>
 303                         </varlistentry>
 304
 305                         <varlistentry>
 306                                 <term><option>-u</option></term>
 307                                 <term><option>--unit=</option></term>
 308
 309                                 <listitem><para>Show data only of the
 310                                 specified unit. This will add a match
 311                                 for <literal>_SYSTEMD_UNIT=</literal>
 312                                 for the specified
 313                                 unit.</para></listitem>
 314                         </varlistentry>
 315
 316                         <varlistentry>
 317                                 <term><option>--user-unit=</option></term>
 318
 319                                 <listitem><para>Show data only of the
 320                                 specified user session unit. This will
 321                                 add a match for
 322                                 <literal>_SYSTEMD_USER_UNIT=</literal>
 323                                 for the specified
 324                                 unit.</para></listitem>
 325                         </varlistentry>
 326
 327                         <varlistentry>
 328                                 <term><option>-p</option></term>
 329                                 <term><option>--priority=</option></term>
 330
 331                                 <listitem><para>Filter output by
 332                                 message priorities or priority
 333                                 ranges. Takes either a single numeric
 334                                 or textual log level (i.e. between
 335                                 0/<literal>emerg</literal> and
 336                                 7/<literal>debug</literal>), or a
 337                                 range of numeric/text log levels in
 338                                 the form FROM..TO. The log levels are
 339                                 the usual syslog log levels as
 340                                 documented in
 341                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 342                                 i.e. <literal>emerg</literal> (0),
 343                                 <literal>alert</literal> (1),
 344                                 <literal>crit</literal> (2),
 345                                 <literal>err</literal> (3),
 346                                 <literal>warning</literal> (4),
 347                                 <literal>notice</literal> (5),
 348                                 <literal>info</literal> (6),
 349                                 <literal>debug</literal> (7). If a
 350                                 single log level is specified all
 351                                 messages with this log level or a
 352                                 lower (hence more important) log level
 353                                 are shown. If a range is specified all
 354                                 messages within the range are shown,
 355                                 including both the start and the end
 356                                 value of the range. This will add
 357                                 <literal>PRIORITY=</literal> matches
 358                                 for the specified
 359                                 priorities.</para></listitem>
 360                         </varlistentry>
 361
 362                         <varlistentry>
 363                                 <term><option>-c</option></term>
 364                                 <term><option>--cursor=</option></term>
 365
 366                                 <listitem><para>Start showing entries
 367                                 from the location in the journal
 368                                 specified by the passed
 369                                 cursor.</para></listitem>
 370                         </varlistentry>
 371
 372                         <varlistentry>
 373                                 <term><option>--since=</option></term>
 374                                 <term><option>--until=</option></term>
 375
 376                                 <listitem><para>Start showing entries
 377                                 on or newer than the specified date,
 378                                 or on or older than the specified
 379                                 date, respectively. Date specifications should be of
 380                                 the format "2012-10-30 18:17:16". If
 381                                 the time part is omitted, 00:00:00 is
 382                                 assumed. If only the seconds component
 383                                 is omitted, :00 is assumed. If the
 384                                 date component is omitted, the
 385                                 current day is assumed. Alternatively
 386                                 the strings
 387                                 <literal>yesterday</literal>,
 388                                 <literal>today</literal>,
 389                                 <literal>tomorrow</literal> are
 390                                 understood, which refer to 00:00:00 of
 391                                 the day before the current day, the
 392                                 current day, or the day after the
 393                                 current day, respectively. <literal>now</literal>
 394                                 refers to the current time. Finally,
 395                                 relative times may be specified,
 396                                 prefixed with <literal>-</literal> or
 397                                 <literal>+</literal>, referring to
 398                                 times before or after the current
 399                                 time, respectively.</para></listitem>
 400                         </varlistentry>
 401
 402                         <varlistentry>
 403                                 <term><option>-F</option></term>
 404                                 <term><option>--field=</option></term>
 405
 406                                 <listitem><para>Print all possible
 407                                 data values the specified field can
 408                                 take in all entries of the
 409                                 journal.</para></listitem>
 410                         </varlistentry>
 411
 412                         <varlistentry>
 413                                 <term><option>-D</option></term>
 414                                 <term><option>--directory=</option></term>
 415
 416                                 <listitem><para>Takes an absolute
 417                                 directory path as argument. If
 418                                 specified journalctl will operate on the
 419                                 specified journal directory instead of
 420                                 the default runtime and system journal
 421                                 paths.</para></listitem>
 422                         </varlistentry>
 423
 424                         <varlistentry>
 425                                 <term><option>--new-id128</option></term>
 426
 427                                 <listitem><para>Instead of showing
 428                                 journal contents generate a new 128
 429                                 bit ID suitable for identifying
 430                                 messages. This is intended for usage
 431                                 by developers who need a new
 432                                 identifier for a new message they
 433                                 introduce and want to make
 434                                 recognizable. Will print the new ID in
 435                                 three different formats which can be
 436                                 copied into source code or
 437                                 similar.</para></listitem>
 438                         </varlistentry>
 439
 440                         <varlistentry>
 441                                 <term><option>--header</option></term>
 442
 443                                 <listitem><para>Instead of showing
 444                                 journal contents show internal header
 445                                 information of the journal fields
 446                                 accessed.</para></listitem>
 447                         </varlistentry>
 448
 449                         <varlistentry>
 450                                 <term><option>--disk-usage</option></term>
 451
 452                                 <listitem><para>Shows the current disk
 453                                 usage of all
 454                                 journal files.</para></listitem>
 455                         </varlistentry>
 456
 457                         <varlistentry>
 458                                 <term><option>--list-catalog</option></term>
 459
 460                                 <listitem><para>List the contents of
 461                                 the message catalog, as table of
 462                                 message IDs plus their short
 463                                 description strings.</para></listitem>
 464                         </varlistentry>
 465
 466                         <varlistentry>
 467                                 <term><option>--update-catalog</option></term>
 468
 469                                 <listitem><para>Update the message
 470                                 catalog index. This command needs to
 471                                 be executed each time new catalog
 472                                 files are installed, removed or
 473                                 updated to rebuild the binary catalog
 474                                 index.</para></listitem>
 475                         </varlistentry>
 476
 477                         <varlistentry>
 478                                 <term><option>--setup-keys</option></term>
 479
 480                                 <listitem><para>Instead of showing
 481                                 journal contents generate a new key
 482                                 pair for Forward Secure Sealing
 483                                 (FSS). This will generate a sealing
 484                                 key and a verification key. The
 485                                 sealing key is stored in the journal
 486                                 data directory and shall remain on the
 487                                 host. The verification key should be
 488                                 stored externally.</para></listitem>
 489                         </varlistentry>
 490
 491                         <varlistentry>
 492                                 <term><option>--interval=</option></term>
 493
 494                                 <listitem><para>Specifies the change
 495                                 interval for the sealing key, when
 496                                 generating an FSS key pair with
 497                                 <option>--setup-keys</option>. Shorter
 498                                 intervals increase CPU consumption but
 499                                 shorten the time range of
 500                                 undetectable journal
 501                                 alterations. Defaults to
 502                                 15min.</para></listitem>
 503                         </varlistentry>
 504
 505                         <varlistentry>
 506                                 <term><option>--verify</option></term>
 507
 508                                 <listitem><para>Check the journal file
 509                                 for internal consistency. If the
 510                                 file has been generated with FSS
 511                                 enabled, and the FSS verification key
 512                                 has been specified with
 513                                 <option>--verify-key=</option>
 514                                 authenticity of the journal file is
 515                                 verified.</para></listitem>
 516                         </varlistentry>
 517
 518                         <varlistentry>
 519                                 <term><option>--verify-key=</option></term>
 520
 521                                 <listitem><para>Specifies the FSS
 522                                 verification key to use for the
 523                                 <option>--verify</option>
 524                                 operation.</para></listitem>
 525                         </varlistentry>
 526
 527                 </variablelist>
 528         </refsect1>
 529
 530         <refsect1>
 531                 <title>Exit status</title>
 532
 533                 <para>On success 0 is returned, a non-zero failure
 534                 code otherwise.</para>
 535         </refsect1>
 536
 537         <refsect1>
 538                 <title>Environment</title>
 539
 540                 <variablelist class='environment-variables'>
 541                         <varlistentry>
 542                                 <term><varname>$SYSTEMD_PAGER</varname></term>
 543                                 <listitem><para>Pager to use when
 544                                 <option>--no-pager</option> is not given;
 545                                 overrides <varname>$PAGER</varname>.  Setting
 546                                 this to an empty string or the value
 547                                 <literal>cat</literal> is equivalent to passing
 548                                 <option>--no-pager</option>.</para></listitem>
 549                         </varlistentry>
 550                 </variablelist>
 551         </refsect1>
 552
 553         <refsect1>
 554                 <title>Examples</title>
 555
 556                 <para>Without arguments all collected logs are shown
 557                 unfiltered:</para>
 558
 559                 <programlisting>journalctl</programlisting>
 560
 561                 <para>With one match specified all entries with a field matching the expression are shown:</para>
 562
 563                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
 564
 565                 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
 566
 567                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
 568
 569                 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
 570
 571                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
 572
 573                 <para>If the separator "<literal>+</literal>" is used
 574                 two expressions may be combined in a logical OR. The
 575                 following will show all messages from the Avahi
 576                 service process with the PID 28097 plus all messages
 577                 from the D-Bus service (from any of its
 578                 processes):</para>
 579
 580                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
 581
 582                 <para>Show all logs generated by the D-Bus executable:</para>
 583
 584                 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
 585
 586                 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
 587
 588                 <programlisting>journalctl /dev/sda</programlisting>
 589
 590         </refsect1>
 591
 592         <refsect1>
 593                 <title>See Also</title>
 594                 <para>
 595                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 596                         <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 597                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 598                         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 599                         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 600                 </para>
 601         </refsect1>
 602
 603 </refentry>