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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  13   (at your option) any later version.
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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 (see <ulink
 216                                 url="http://www.freedesktop.org/wiki/Software/systemd/json">Journal
 217                                 JSON Format</ulink> for more
 218                                 information). <literal>json-pretty</literal>
 219                                 also formats entries as JSON data
 220                                 structures, but formats them in
 221                                 multiple lines in order to make them
 222                                 more readable for
 223                                 humans. <literal>json-sse</literal>
 224                                 also formats entries as JSON data
 225                                 structures, but wraps them in a format
 226                                 suitable for <ulink
 227                                 url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent
 228                                 Events</ulink>. <literal>cat</literal>
 229                                 generates a very terse output only
 230                                 showing the actual message of each
 231                                 journal entry with no meta data, not
 232                                 even a timestamp.</para></listitem>
 233                         </varlistentry>
 234
 235                         <varlistentry>
 236                                 <term><option>--quiet</option></term>
 237                                 <term><option>-q</option></term>
 238
 239                                 <listitem><para>Suppresses any warning
 240                                 message regarding inaccessible system
 241                                 journals when run as normal
 242                                 user.</para></listitem>
 243                         </varlistentry>
 244
 245                         <varlistentry>
 246                                 <term><option>--merge</option></term>
 247                                 <term><option>-m</option></term>
 248
 249                                 <listitem><para>Show entries
 250                                 interleaved from all available
 251                                 journals, including remote
 252                                 ones.</para></listitem>
 253                         </varlistentry>
 254
 255                         <varlistentry>
 256                                 <term><option>--this-boot</option></term>
 257                                 <term><option>-b</option></term>
 258
 259                                 <listitem><para>Show data only from
 260                                 current boot. This will add a match
 261                                 for <literal>_BOOT_ID=</literal> for
 262                                 the current boot ID of the
 263                                 kernel.</para></listitem>
 264                         </varlistentry>
 265
 266                         <varlistentry>
 267                                 <term><option>--unit=</option></term>
 268                                 <term><option>-u</option></term>
 269
 270                                 <listitem><para>Show data only of the
 271                                 specified unit. This will add a match
 272                                 for <literal>_SYSTEMD_UNIT=</literal>
 273                                 for the specified
 274                                 unit.</para></listitem>
 275                         </varlistentry>
 276
 277                         <varlistentry>
 278                                 <term><option>-p</option></term>
 279                                 <term><option>--priority=</option></term>
 280
 281                                 <listitem><para>Filter output by
 282                                 message priorities or priority
 283                                 ranges. Takes either a single numeric
 284                                 or textual log level (i.e. between
 285                                 0/<literal>emerg</literal> and
 286                                 7/<literal>debug</literal>), or a
 287                                 range of numeric/text log levels in
 288                                 the form FROM..TO. The log levels are
 289                                 the usual syslog log levels as
 290                                 documented in
 291                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 292                                 i.e. <literal>emerg</literal> (0),
 293                                 <literal>alert</literal> (1),
 294                                 <literal>crit</literal> (2),
 295                                 <literal>err</literal> (3),
 296                                 <literal>warning</literal> (4),
 297                                 <literal>notice</literal> (5),
 298                                 <literal>info</literal> (6),
 299                                 <literal>debug</literal> (7). If a
 300                                 single log level is specified all
 301                                 messages with this log level or a
 302                                 lower (hence more important) log level
 303                                 are shown. If a range is specified all
 304                                 messages within the range are shown,
 305                                 including both the start and the end
 306                                 value of the range. This will add
 307                                 <literal>PRIORITY=</literal> matches
 308                                 for the specified
 309                                 priorities.</para></listitem>
 310                         </varlistentry>
 311
 312                         <varlistentry>
 313                                 <term><option>--cursor=</option></term>
 314                                 <term><option>-c</option></term>
 315
 316                                 <listitem><para>Start showing entries
 317                                 from the location in the journal
 318                                 specified by the passed
 319                                 cursor.</para></listitem>
 320                         </varlistentry>
 321
 322                         <varlistentry>
 323                                 <term><option>--since=</option></term>
 324                                 <term><option>--until=</option></term>
 325
 326                                 <listitem><para>Start showing entries
 327                                 on or newer than the specified date,
 328                                 or on or older than the specified
 329                                 date, respectively. Date specifications should be of
 330                                 the format "2012-10-30 18:17:16". If
 331                                 the time part is omitted, 00:00:00 is
 332                                 assumed. If only the seconds component
 333                                 is omitted, :00 is assumed. If the
 334                                 date component is ommitted, the
 335                                 current day is assumed. Alternatively
 336                                 the strings
 337                                 <literal>yesterday</literal>,
 338                                 <literal>today</literal>,
 339                                 <literal>tomorrow</literal> are
 340                                 understood, which refer to 00:00:00 of
 341                                 the day before the current day, the
 342                                 current day, or the day after the
 343                                 current day, respectively. <literal>now</literal>
 344                                 refers to the current time. Finally,
 345                                 relative times may be specified,
 346                                 prefixed with <literal>-</literal> or
 347                                 <literal>+</literal>, referring to
 348                                 times before or after the current
 349                                 time, respectively.</para></listitem>
 350                         </varlistentry>
 351
 352                         <varlistentry>
 353                                 <term><option>--field=</option></term>
 354                                 <term><option>-F</option></term>
 355
 356                                 <listitem><para>Print all possible
 357                                 data values the specified field can
 358                                 take in all entries of the
 359                                 journal.</para></listitem>
 360                         </varlistentry>
 361
 362                         <varlistentry>
 363                                 <term><option>--directory=</option></term>
 364                                 <term><option>-D</option></term>
 365
 366                                 <listitem><para>Takes an absolute
 367                                 directory path as argument. If
 368                                 specified journalctl will operate on the
 369                                 specified journal directory instead of
 370                                 the default runtime and system journal
 371                                 paths.</para></listitem>
 372                         </varlistentry>
 373
 374                         <varlistentry>
 375                                 <term><option>--new-id128</option></term>
 376
 377                                 <listitem><para>Instead of showing
 378                                 journal contents generate a new 128
 379                                 bit ID suitable for identifying
 380                                 messages. This is intended for usage
 381                                 by developers who need a new
 382                                 identifier for a new message they
 383                                 introduce and want to make
 384                                 recognizable. Will print the new ID in
 385                                 three different formats which can be
 386                                 copied into source code or
 387                                 similar.</para></listitem>
 388                         </varlistentry>
 389
 390                         <varlistentry>
 391                                 <term><option>--header</option></term>
 392
 393                                 <listitem><para>Instead of showing
 394                                 journal contents show internal header
 395                                 information of the journal fields
 396                                 accessed.</para></listitem>
 397                         </varlistentry>
 398
 399                         <varlistentry>
 400                                 <term><option>--disk-usage</option></term>
 401
 402                                 <listitem><para>Shows the current disk
 403                                 usage of all
 404                                 journal files.</para></listitem>
 405                         </varlistentry>
 406
 407                         <varlistentry>
 408                                 <term><option>--setup-keys</option></term>
 409
 410                                 <listitem><para>Instead of showing
 411                                 journal contents generate a new key
 412                                 pair for Forward Secure Sealing
 413                                 (FSS). This will generate a sealing
 414                                 key and a verification key. The
 415                                 sealing key is stored in the journal
 416                                 data directory and shall remain on the
 417                                 host. The verification key should be
 418                                 stored externally.</para></listitem>
 419                         </varlistentry>
 420
 421                         <varlistentry>
 422                                 <term><option>--interval=</option></term>
 423
 424                                 <listitem><para>Specifies the change
 425                                 interval for the sealing key, when
 426                                 generating an FSS key pair with
 427                                 <option>--setup-keys</option>. Shorter
 428                                 intervals increase CPU consumption but
 429                                 shorten the time range of
 430                                 undetectable journal
 431                                 alterations. Defaults to
 432                                 15min.</para></listitem>
 433                         </varlistentry>
 434
 435                         <varlistentry>
 436                                 <term><option>--verify</option></term>
 437
 438                                 <listitem><para>Check the journal file
 439                                 for internal consistency. If the
 440                                 file has been generated with FSS
 441                                 enabled, and the FSS verification key
 442                                 has been specified with
 443                                 <option>--verify-key=</option>
 444                                 authenticity of the journal file is
 445                                 verified.</para></listitem>
 446                         </varlistentry>
 447
 448                         <varlistentry>
 449                                 <term><option>--verify-key=</option></term>
 450
 451                                 <listitem><para>Specifies the FSS
 452                                 verification key to use for the
 453                                 <option>--verify</option>
 454                                 operation.</para></listitem>
 455                         </varlistentry>
 456
 457                 </variablelist>
 458         </refsect1>
 459
 460         <refsect1>
 461                 <title>Exit status</title>
 462
 463                 <para>On success 0 is returned, a non-zero failure
 464                 code otherwise.</para>
 465         </refsect1>
 466
 467         <refsect1>
 468                 <title>Environment</title>
 469
 470                 <variablelist>
 471                         <varlistentry>
 472                                 <term><varname>$SYSTEMD_PAGER</varname></term>
 473                                 <listitem><para>Pager to use when
 474                                 <option>--no-pager</option> is not given;
 475                                 overrides <varname>$PAGER</varname>.  Setting
 476                                 this to an empty string or the value
 477                                 <literal>cat</literal> is equivalent to passing
 478                                 <option>--no-pager</option>.</para></listitem>
 479                         </varlistentry>
 480                 </variablelist>
 481         </refsect1>
 482
 483         <refsect1>
 484                 <title>Examples</title>
 485
 486                 <para>Without arguments all collected logs are shown
 487                 unfiltered:</para>
 488
 489                 <programlisting>journalctl</programlisting>
 490
 491                 <para>With one match specified all entries with a field matching the expression are shown:</para>
 492
 493                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
 494
 495                 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
 496
 497                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
 498
 499                 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
 500
 501                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
 502
 503                 <para>If the separator "<literal>+</literal>" is used
 504                 two expressions may be combined in a logical OR. The
 505                 following will show all messages from the Avahi
 506                 service process with the PID 28097 plus all messages
 507                 from the D-Bus service (from any of its
 508                 processes):</para>
 509
 510                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
 511
 512                 <para>Show all logs generated by the D-Bus executable:</para>
 513
 514                 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
 515
 516                 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
 517
 518                 <programlisting>journalctl /dev/sda</programlisting>
 519
 520         </refsect1>
 521
 522         <refsect1>
 523                 <title>See Also</title>
 524                 <para>
 525                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 526                         <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 527                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 528                         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 529                         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 530                 </para>
 531         </refsect1>
 532
 533 </refentry>