man/journalctl.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
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   6   This file is part of systemd.
   7
   8   Copyright 2012 Lennart Poettering
   9
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  11   under the terms of the GNU Lesser General Public License as published by
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  18   Lesser General Public License for more details.
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  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
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  23
  24 <refentry id="journalctl">
  25
  26         <refentryinfo>
  27                 <title>journalctl</title>
  28                 <productname>systemd</productname>
  29
  30                 <authorgroup>
  31                         <author>
  32                                 <contrib>Developer</contrib>
  33                                 <firstname>Lennart</firstname>
  34                                 <surname>Poettering</surname>
  35                                 <email>lennart@poettering.net</email>
  36                         </author>
  37                 </authorgroup>
  38         </refentryinfo>
  39
  40         <refmeta>
  41                 <refentrytitle>journalctl</refentrytitle>
  42                 <manvolnum>1</manvolnum>
  43         </refmeta>
  44
  45         <refnamediv>
  46                 <refname>journalctl</refname>
  47                 <refpurpose>Query the systemd journal</refpurpose>
  48         </refnamediv>
  49
  50         <refsynopsisdiv>
  51                 <cmdsynopsis>
  52                         <command>journalctl <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>--all</option></term>
 140                                 <term><option>-a</option></term>
 141
 142                                 <listitem><para>Show all fields in
 143                                 full, even if they include unprintable
 144                                 characters or are very
 145                                 long.</para></listitem>
 146                         </varlistentry>
 147
 148                         <varlistentry>
 149                                 <term><option>--follow</option></term>
 150                                 <term><option>-f</option></term>
 151
 152                                 <listitem><para>Show only the most recent
 153                                 journal entries, and continuously print
 154                                 new entries as they are appended to
 155                                 the journal.</para></listitem>
 156                         </varlistentry>
 157
 158                         <varlistentry>
 159                                 <term><option>--lines=</option></term>
 160                                 <term><option>-n</option></term>
 161
 162                                 <listitem><para>Show the most recent
 163                                 journal events and limit the number of
 164                                 events shown. If
 165                                 <option>--follow</option> is used,
 166                                 this option is implied. The argument,
 167                                 a positive integer, is optional, and
 168                                 defaults to 10. </para></listitem>
 169                         </varlistentry>
 170
 171                         <varlistentry>
 172                                 <term><option>--no-tail</option></term>
 173
 174                                 <listitem><para>Show all stored output
 175                                 lines, even in follow mode. Undoes the
 176                                 effect of
 177                                 <option>--lines=</option>.</para></listitem>
 178                         </varlistentry>
 179
 180                         <varlistentry>
 181                                 <term><option>--output=</option></term>
 182                                 <term><option>-o</option></term>
 183
 184                                 <listitem><para>Controls the
 185                                 formatting of the journal entries that
 186                                 are shown. Takes one of
 187                                 <literal>short</literal>,
 188                                 <literal>short-monotonic</literal>,
 189                                 <literal>verbose</literal>,
 190                                 <literal>export</literal>,
 191                                 <literal>json</literal>,
 192                                 <literal>json-pretty</literal>,
 193                                 <literal>json-sse</literal>,
 194                                 <literal>cat</literal>. <literal>short</literal>
 195                                 is the default and generates an output
 196                                 that is mostly identical to the
 197                                 formatting of classic syslog log
 198                                 files, showing one line per journal
 199                                 entry. <literal>short-monotonic</literal>
 200                                 is very similar but shows monotonic
 201                                 timestamps instead of wallclock
 202                                 timestamps. <literal>verbose</literal>
 203                                 shows the full structured entry items
 204                                 with all
 205                                 fields. <literal>export</literal>
 206                                 serializes the journal into a binary
 207                                 (but mostly text-based) stream
 208                                 suitable for backups and network
 209                                 transfer (see <ulink
 210                                 url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal
 211                                 Export Format</ulink> for more
 212                                 information). <literal>json</literal>
 213                                 formats entries as JSON data
 214                                 structures, one per
 215                                 line. <literal>json-pretty</literal>
 216                                 also formats entries as JSON data
 217                                 structures, but formats them in
 218                                 multiple lines in order to make them
 219                                 more readable for
 220                                 humans. <literal>json-sse</literal>
 221                                 also formats entries as JSON data
 222                                 structures, but wraps them in a format
 223                                 suitable for <ulink
 224                                 url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent
 225                                 Events</ulink>. <literal>cat</literal>
 226                                 generates a very terse output only
 227                                 showing the actual message of each
 228                                 journal entry with no meta data, not
 229                                 even a timestamp.</para></listitem>
 230                         </varlistentry>
 231
 232                         <varlistentry>
 233                                 <term><option>--quiet</option></term>
 234                                 <term><option>-q</option></term>
 235
 236                                 <listitem><para>Suppresses any warning
 237                                 message regarding inaccessible system
 238                                 journals when run as normal
 239                                 user.</para></listitem>
 240                         </varlistentry>
 241
 242                         <varlistentry>
 243                                 <term><option>--merge</option></term>
 244                                 <term><option>-m</option></term>
 245
 246                                 <listitem><para>Show entries
 247                                 interleaved from all available
 248                                 journals, including remote
 249                                 ones.</para></listitem>
 250                         </varlistentry>
 251
 252                         <varlistentry>
 253                                 <term><option>--this-boot</option></term>
 254                                 <term><option>-b</option></term>
 255
 256                                 <listitem><para>Show data only from
 257                                 current boot. This will add a match
 258                                 for <literal>_BOOT_ID=</literal> for
 259                                 the current boot ID of the
 260                                 kernel.</para></listitem>
 261                         </varlistentry>
 262
 263                         <varlistentry>
 264                                 <term><option>--unit=</option></term>
 265                                 <term><option>-u</option></term>
 266
 267                                 <listitem><para>Show data only of the
 268                                 specified unit. This will add a match
 269                                 for <literal>_SYSTEMD_UNIT=</literal>
 270                                 for the specified
 271                                 unit.</para></listitem>
 272                         </varlistentry>
 273
 274                         <varlistentry>
 275                                 <term><option>-p</option></term>
 276                                 <term><option>--priority=</option></term>
 277
 278                                 <listitem><para>Filter output by
 279                                 message priorities or priority
 280                                 ranges. Takes either a single numeric
 281                                 or textual log level (i.e. between
 282                                 0/<literal>emerg</literal> and
 283                                 7/<literal>debug</literal>), or a
 284                                 range of numeric/text log levels in
 285                                 the form FROM..TO. The log levels are
 286                                 the usual syslog log levels as
 287                                 documented in
 288                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 289                                 i.e. <literal>emerg</literal> (0),
 290                                 <literal>alert</literal> (1),
 291                                 <literal>crit</literal> (2),
 292                                 <literal>err</literal> (3),
 293                                 <literal>warning</literal> (4),
 294                                 <literal>notice</literal> (5),
 295                                 <literal>info</literal> (6),
 296                                 <literal>debug</literal> (7). If a
 297                                 single log level is specified all
 298                                 messages with this log level or a
 299                                 lower (hence more important) log level
 300                                 are shown. If a range is specified all
 301                                 messages within the range are shown,
 302                                 including both the start and the end
 303                                 value of the range. This will add
 304                                 <literal>PRIORITY=</literal> matches
 305                                 for the specified
 306                                 priorities.</para></listitem>
 307                         </varlistentry>
 308
 309                         <varlistentry>
 310                                 <term><option>--cursor=</option></term>
 311                                 <term><option>-c</option></term>
 312
 313                                 <listitem><para>Start showing entries
 314                                 from the location in the journal
 315                                 specified by the passed
 316                                 cursor.</para></listitem>
 317                         </varlistentry>
 318
 319                         <varlistentry>
 320                                 <term><option>--since=</option></term>
 321                                 <term><option>--until=</option></term>
 322
 323                                 <listitem><para>Start showing entries
 324                                 on or newer than the specified date,
 325                                 or on or older than the specified
 326                                 date, respectively. Date specifications should be of
 327                                 the format "2012-10-30 18:17:16". If
 328                                 the time part is omitted, 00:00:00 is
 329                                 assumed. If only the seconds component
 330                                 is omitted, :00 is assumed. If the
 331                                 date component is ommitted, the
 332                                 current day is assumed. Alternatively
 333                                 the strings
 334                                 <literal>yesterday</literal>,
 335                                 <literal>today</literal>,
 336                                 <literal>tomorrow</literal> are
 337                                 understood, which refer to 00:00:00 of
 338                                 the day before the current day, the
 339                                 current day, or the day after the
 340                                 current day, respectively. <literal>now</literal>
 341                                 refers to the current time. Finally,
 342                                 relative times may be specified,
 343                                 prefixed with <literal>-</literal> or
 344                                 <literal>+</literal>, referring to
 345                                 times before or after the current
 346                                 time, respectively.</para></listitem>
 347                         </varlistentry>
 348
 349                         <varlistentry>
 350                                 <term><option>--field=</option></term>
 351                                 <term><option>-F</option></term>
 352
 353                                 <listitem><para>Print all possible
 354                                 data values the specified field can
 355                                 take in all entries of the
 356                                 journal.</para></listitem>
 357                         </varlistentry>
 358
 359                         <varlistentry>
 360                                 <term><option>--directory=</option></term>
 361                                 <term><option>-D</option></term>
 362
 363                                 <listitem><para>Takes an absolute
 364                                 directory path as argument. If
 365                                 specified journalctl will operate on the
 366                                 specified journal directory instead of
 367                                 the default runtime and system journal
 368                                 paths.</para></listitem>
 369                         </varlistentry>
 370
 371                         <varlistentry>
 372                                 <term><option>--new-id128</option></term>
 373
 374                                 <listitem><para>Instead of showing
 375                                 journal contents generate a new 128
 376                                 bit ID suitable for identifying
 377                                 messages. This is intended for usage
 378                                 by developers who need a new
 379                                 identifier for a new message they
 380                                 introduce and want to make
 381                                 recognizable. Will print the new ID in
 382                                 three different formats which can be
 383                                 copied into source code or
 384                                 similar.</para></listitem>
 385                         </varlistentry>
 386
 387                         <varlistentry>
 388                                 <term><option>--header</option></term>
 389
 390                                 <listitem><para>Instead of showing
 391                                 journal contents show internal header
 392                                 information of the journal fields
 393                                 accessed.</para></listitem>
 394                         </varlistentry>
 395
 396                         <varlistentry>
 397                                 <term><option>--disk-usage</option></term>
 398
 399                                 <listitem><para>Shows the current disk
 400                                 usage of all
 401                                 journal files.</para></listitem>
 402                         </varlistentry>
 403
 404                         <varlistentry>
 405                                 <term><option>--setup-keys</option></term>
 406
 407                                 <listitem><para>Instead of showing
 408                                 journal contents generate a new key
 409                                 pair for Forward Secure Sealing
 410                                 (FSS). This will generate a sealing
 411                                 key and a verification key. The
 412                                 sealing key is stored in the journal
 413                                 data directory and shall remain on the
 414                                 host. The verification key should be
 415                                 stored externally.</para></listitem>
 416                         </varlistentry>
 417
 418                         <varlistentry>
 419                                 <term><option>--interval=</option></term>
 420
 421                                 <listitem><para>Specifies the change
 422                                 interval for the sealing key, when
 423                                 generating an FSS key pair with
 424                                 <option>--setup-keys</option>. Shorter
 425                                 intervals increase CPU consumption but
 426                                 shorten the time range of
 427                                 undetectable journal
 428                                 alterations. Defaults to
 429                                 15min.</para></listitem>
 430                         </varlistentry>
 431
 432                         <varlistentry>
 433                                 <term><option>--verify</option></term>
 434
 435                                 <listitem><para>Check the journal file
 436                                 for internal consistency. If the
 437                                 file has been generated with FSS
 438                                 enabled, and the FSS verification key
 439                                 has been specified with
 440                                 <option>--verify-key=</option>
 441                                 authenticity of the journal file is
 442                                 verified.</para></listitem>
 443                         </varlistentry>
 444
 445                         <varlistentry>
 446                                 <term><option>--verify-key=</option></term>
 447
 448                                 <listitem><para>Specifies the FSS
 449                                 verification key to use for the
 450                                 <option>--verify</option>
 451                                 operation.</para></listitem>
 452                         </varlistentry>
 453
 454                 </variablelist>
 455         </refsect1>
 456
 457         <refsect1>
 458                 <title>Exit status</title>
 459
 460                 <para>On success 0 is returned, a non-zero failure
 461                 code otherwise.</para>
 462         </refsect1>
 463
 464         <refsect1>
 465                 <title>Environment</title>
 466
 467                 <variablelist>
 468                         <varlistentry>
 469                                 <term><varname>$SYSTEMD_PAGER</varname></term>
 470                                 <listitem><para>Pager to use when
 471                                 <option>--no-pager</option> is not given;
 472                                 overrides <varname>$PAGER</varname>.  Setting
 473                                 this to an empty string or the value
 474                                 <literal>cat</literal> is equivalent to passing
 475                                 <option>--no-pager</option>.</para></listitem>
 476                         </varlistentry>
 477                 </variablelist>
 478         </refsect1>
 479
 480         <refsect1>
 481                 <title>Examples</title>
 482
 483                 <para>Without arguments all collected logs are shown
 484                 unfiltered:</para>
 485
 486                 <programlisting>journalctl</programlisting>
 487
 488                 <para>With one match specified all entries with a field matching the expression are shown:</para>
 489
 490                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
 491
 492                 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
 493
 494                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
 495
 496                 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
 497
 498                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
 499
 500                 <para>If the separator "<literal>+</literal>" is used
 501                 two expressions may be combined in a logical OR. The
 502                 following will show all messages from the Avahi
 503                 service process with the PID 28097 plus all messages
 504                 from the D-Bus service (from any of its
 505                 processes):</para>
 506
 507                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
 508
 509                 <para>Show all logs generated by the D-Bus executable:</para>
 510
 511                 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
 512
 513                 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
 514
 515                 <programlisting>journalctl /dev/sda</programlisting>
 516
 517         </refsect1>
 518
 519         <refsect1>
 520                 <title>See Also</title>
 521                 <para>
 522                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 523                         <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 524                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 525                         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 526                         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 527                 </para>
 528         </refsect1>
 529
 530 </refentry>