man/journalctl.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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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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  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>Controls the number of
 163                                 journal lines to show, counting from
 164                                 the most recent ones. The argument is
 165                                 optional, and if specified is a
 166                                 positive integer. If not specified and
 167                                 in follow mode defaults to 10. If this
 168                                 option is not passed and follow mode
 169                                 is not enabled, how many lines are
 170                                 shown is not
 171                                 limited.</para></listitem>
 172                         </varlistentry>
 173
 174                         <varlistentry>
 175                                 <term><option>--no-tail</option></term>
 176
 177                                 <listitem><para>Show all stored output
 178                                 lines, even in follow mode. Undoes the
 179                                 effect of
 180                                 <option>--lines=</option>.</para></listitem>
 181                         </varlistentry>
 182
 183                         <varlistentry>
 184                                 <term><option>--output=</option></term>
 185                                 <term><option>-o</option></term>
 186
 187                                 <listitem><para>Controls the
 188                                 formatting of the journal entries that
 189                                 are shown. Takes one of
 190                                 <literal>short</literal>,
 191                                 <literal>short-monotonic</literal>,
 192                                 <literal>verbose</literal>,
 193                                 <literal>export</literal>,
 194                                 <literal>json</literal>,
 195                                 <literal>json-pretty</literal>,
 196                                 <literal>json-sse</literal>,
 197                                 <literal>cat</literal>. <literal>short</literal>
 198                                 is the default and generates an output
 199                                 that is mostly identical to the
 200                                 formatting of classic syslog log
 201                                 files, showing one line per journal
 202                                 entry. <literal>short-monotonic</literal>
 203                                 is very similar but shows monotonic
 204                                 timestamps instead of wallclock
 205                                 timestamps. <literal>verbose</literal>
 206                                 shows the full structured entry items
 207                                 with all
 208                                 fields. <literal>export</literal>
 209                                 serializes the journal into a binary
 210                                 (but mostly text-based) stream
 211                                 suitable for backups and network
 212                                 transfer (see <ulink
 213                                 url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal
 214                                 Export Format</ulink> for more
 215                                 information). <literal>json</literal>
 216                                 formats entries as JSON data
 217                                 structures, one per
 218                                 line. <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>--directory=</option></term>
 354                                 <term><option>-D</option></term>
 355
 356                                 <listitem><para>Takes an absolute
 357                                 directory path as argument. If
 358                                 specified journalctl will operate on the
 359                                 specified journal directory instead of
 360                                 the default runtime and system journal
 361                                 paths.</para></listitem>
 362                         </varlistentry>
 363
 364                         <varlistentry>
 365                                 <term><option>--new-id128</option></term>
 366
 367                                 <listitem><para>Instead of showing
 368                                 journal contents generate a new 128
 369                                 bit ID suitable for identifying
 370                                 messages. This is intended for usage
 371                                 by developers who need a new
 372                                 identifier for a new message they
 373                                 introduce and want to make
 374                                 recognizable. Will print the new ID in
 375                                 three different formats which can be
 376                                 copied into source code or
 377                                 similar.</para></listitem>
 378                         </varlistentry>
 379
 380                         <varlistentry>
 381                                 <term><option>--header</option></term>
 382
 383                                 <listitem><para>Instead of showing
 384                                 journal contents show internal header
 385                                 information of the journal fields
 386                                 accessed.</para></listitem>
 387                         </varlistentry>
 388
 389                         <varlistentry>
 390                                 <term><option>--disk-usage</option></term>
 391
 392                                 <listitem><para>Shows the current disk
 393                                 usage of all
 394                                 journal files.</para></listitem>
 395                         </varlistentry>
 396
 397                         <varlistentry>
 398                                 <term><option>--setup-keys</option></term>
 399
 400                                 <listitem><para>Instead of showing
 401                                 journal contents generate a new key
 402                                 pair for Forward Secure Sealing
 403                                 (FSS). This will generate a sealing
 404                                 key and a verification key. The
 405                                 sealing key is stored in the journal
 406                                 data directory and shall remain on the
 407                                 host. The verification key should be
 408                                 stored externally.</para></listitem>
 409                         </varlistentry>
 410
 411                         <varlistentry>
 412                                 <term><option>--interval=</option></term>
 413
 414                                 <listitem><para>Specifies the change
 415                                 interval for the sealing key, when
 416                                 generating an FSS key pair with
 417                                 <option>--setup-keys</option>. Shorter
 418                                 intervals increase CPU consumption but
 419                                 shorten the time range of
 420                                 undetectable journal
 421                                 alterations. Defaults to
 422                                 15min.</para></listitem>
 423                         </varlistentry>
 424
 425                         <varlistentry>
 426                                 <term><option>--verify</option></term>
 427
 428                                 <listitem><para>Check the journal file
 429                                 for internal consistency. If the
 430                                 file has been generated with FSS
 431                                 enabled, and the FSS verification key
 432                                 has been specified with
 433                                 <option>--verify-key=</option>
 434                                 authenticity of the journal file is
 435                                 verified.</para></listitem>
 436                         </varlistentry>
 437
 438                         <varlistentry>
 439                                 <term><option>--verify-key=</option></term>
 440
 441                                 <listitem><para>Specifies the FSS
 442                                 verification key to use for the
 443                                 <option>--verify</option>
 444                                 operation.</para></listitem>
 445                         </varlistentry>
 446
 447                 </variablelist>
 448         </refsect1>
 449
 450         <refsect1>
 451                 <title>Exit status</title>
 452
 453                 <para>On success 0 is returned, a non-zero failure
 454                 code otherwise.</para>
 455         </refsect1>
 456
 457         <refsect1>
 458                 <title>Environment</title>
 459
 460                 <variablelist>
 461                         <varlistentry>
 462                                 <term><varname>$SYSTEMD_PAGER</varname></term>
 463                                 <listitem><para>Pager to use when
 464                                 <option>--no-pager</option> is not given;
 465                                 overrides <varname>$PAGER</varname>.  Setting
 466                                 this to an empty string or the value
 467                                 <literal>cat</literal> is equivalent to passing
 468                                 <option>--no-pager</option>.</para></listitem>
 469                         </varlistentry>
 470                 </variablelist>
 471         </refsect1>
 472
 473         <refsect1>
 474                 <title>Examples</title>
 475
 476                 <para>Without arguments all collected logs are shown
 477                 unfiltered:</para>
 478
 479                 <programlisting>journalctl</programlisting>
 480
 481                 <para>With one match specified all entries with a field matching the expression are shown:</para>
 482
 483                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
 484
 485                 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
 486
 487                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
 488
 489                 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
 490
 491                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
 492
 493                 <para>If the separator "<literal>+</literal>" is used
 494                 two expressions may be combined in a logical OR. The
 495                 following will show all messages from the Avahi
 496                 service process with the PID 28097 plus all messages
 497                 from the D-Bus service (from any of its
 498                 processes):</para>
 499
 500                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
 501
 502                 <para>Show all logs generated by the D-Bus executable:</para>
 503
 504                 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
 505
 506                 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
 507
 508                 <programlisting>journalctl /dev/sda</programlisting>
 509
 510         </refsect1>
 511
 512         <refsect1>
 513                 <title>See Also</title>
 514                 <para>
 515                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 516                         <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 517                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 518                         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 519                         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 520                 </para>
 521         </refsect1>
 522
 523 </refentry>