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.
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   8   Copyright 2012 Lennart Poettering
   9
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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.</para></listitem>
 261                         </varlistentry>
 262
 263                         <varlistentry>
 264                                 <term><option>--cursor=</option></term>
 265                                 <term><option>-c</option></term>
 266
 267                                 <listitem><para>Start showing entries
 268                                 from the location in the journal
 269                                 specified by the passed
 270                                 cursor.</para></listitem>
 271                         </varlistentry>
 272
 273                         <varlistentry>
 274                                 <term><option>--since=</option></term>
 275                                 <term><option>--until=</option></term>
 276
 277                                 <listitem><para>Start showing entries
 278                                 newer or of the specified date,
 279                                 resp. older or of the specified
 280                                 date. Date specifications should be of
 281                                 the format "2012-10-30 18:17:16". If
 282                                 the time part is omitted, 00:00:00 is
 283                                 assumed. If only the seconds component
 284                                 is omitted, :00 is assumed. If the
 285                                 date component is ommitted, the
 286                                 current day is assumed. Alternatively
 287                                 the strings
 288                                 <literal>yesterday</literal>,
 289                                 <literal>today</literal>,
 290                                 <literal>tomorrow</literal> are
 291                                 understood, which refer to 00:00:00 of
 292                                 the day before the current day, the
 293                                 current day, resp the day after the
 294                                 current day. <literal>now</literal>
 295                                 refers to the current time. Finally,
 296                                 relative times may be specified,
 297                                 prefixed with <literal>-</literal> or
 298                                 <literal>+</literal>, referring to
 299                                 times before resp. after the current
 300                                 time.</para></listitem>
 301                         </varlistentry>
 302
 303                         <varlistentry>
 304                                 <term><option>--directory=</option></term>
 305                                 <term><option>-D</option></term>
 306
 307                                 <listitem><para>Takes an absolute
 308                                 directory path as argument. If
 309                                 specified journalctl will operate on the
 310                                 specified journal directory instead of
 311                                 the default runtime and system journal
 312                                 paths.</para></listitem>
 313                         </varlistentry>
 314
 315                         <varlistentry>
 316                                 <term><option>-p</option></term>
 317                                 <term><option>--priority=</option></term>
 318
 319                                 <listitem><para>Filter output by
 320                                 message priorities or priority
 321                                 ranges. Takes either a single numeric
 322                                 or textual log level (i.e. between
 323                                 0/<literal>emerg</literal> and
 324                                 7/<literal>debug</literal>), or a
 325                                 range of numeric/text log levels in
 326                                 the form FROM..TO. The log levels are
 327                                 the usual syslog log levels as
 328                                 documented in
 329                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 330                                 i.e. <literal>emerg</literal> (0),
 331                                 <literal>alert</literal> (1),
 332                                 <literal>crit</literal> (2),
 333                                 <literal>err</literal> (3),
 334                                 <literal>warning</literal> (4),
 335                                 <literal>notice</literal> (5),
 336                                 <literal>info</literal> (6),
 337                                 <literal>debug</literal> (7). If a
 338                                 single log level is specified all
 339                                 messages with this log level or a
 340                                 lower (hence more important) log level
 341                                 are shown. If a range is specified all
 342                                 messages within the range are shown,
 343                                 including both the start and the end
 344                                 value of the range.</para></listitem>
 345                         </varlistentry>
 346
 347                         <varlistentry>
 348                                 <term><option>--new-id128</option></term>
 349
 350                                 <listitem><para>Instead of showing
 351                                 journal contents generate a new 128
 352                                 bit ID suitable for identifying
 353                                 messages. This is intended for usage
 354                                 by developers who need a new
 355                                 identifier for a new message they
 356                                 introduce and want to make
 357                                 recognizable. Will print the new ID in
 358                                 three different formats which can be
 359                                 copied into source code or
 360                                 similar.</para></listitem>
 361                         </varlistentry>
 362
 363                         <varlistentry>
 364                                 <term><option>--header</option></term>
 365
 366                                 <listitem><para>Instead of showing
 367                                 journal contents show internal header
 368                                 information of the journal fields
 369                                 accessed.</para></listitem>
 370                         </varlistentry>
 371
 372                         <varlistentry>
 373                                 <term><option>--disk-usage</option></term>
 374
 375                                 <listitem><para>Shows the current disk
 376                                 usage of all
 377                                 journal files.</para></listitem>
 378                         </varlistentry>
 379
 380                         <varlistentry>
 381                                 <term><option>--setup-keys</option></term>
 382
 383                                 <listitem><para>Instead of showing
 384                                 journal contents generate a new key
 385                                 pair for Forward Secure Sealing
 386                                 (FSS). This will generate a sealing
 387                                 key and a verification key. The
 388                                 sealing key is stored in the journal
 389                                 data directory and shall remain on the
 390                                 host. The verification key should be
 391                                 stored externally.</para></listitem>
 392                         </varlistentry>
 393
 394                         <varlistentry>
 395                                 <term><option>--interval=</option></term>
 396
 397                                 <listitem><para>Specifies the change
 398                                 interval for the sealing key, when
 399                                 generating an FSS key pair with
 400                                 <option>--setup-keys</option>. Shorter
 401                                 intervals increase CPU consumption but
 402                                 shorten the time range of
 403                                 undetectable journal
 404                                 alterations. Defaults to
 405                                 15min.</para></listitem>
 406                         </varlistentry>
 407
 408                         <varlistentry>
 409                                 <term><option>--verify</option></term>
 410
 411                                 <listitem><para>Check the journal file
 412                                 for internal consistency. If the
 413                                 file has been generated with FSS
 414                                 enabled, and the FSS verification key
 415                                 has been specified with
 416                                 <option>--verify-key=</option>
 417                                 authenticity of the journal file is
 418                                 verified.</para></listitem>
 419                         </varlistentry>
 420
 421                         <varlistentry>
 422                                 <term><option>--verify-key=</option></term>
 423
 424                                 <listitem><para>Specifies the FSS
 425                                 verification key to use for the
 426                                 <option>--verify</option>
 427                                 operation.</para></listitem>
 428                         </varlistentry>
 429
 430                 </variablelist>
 431         </refsect1>
 432
 433         <refsect1>
 434                 <title>Exit status</title>
 435
 436                 <para>On success 0 is returned, a non-zero failure
 437                 code otherwise.</para>
 438         </refsect1>
 439
 440         <refsect1>
 441                 <title>Environment</title>
 442
 443                 <variablelist>
 444                         <varlistentry>
 445                                 <term><varname>$SYSTEMD_PAGER</varname></term>
 446                                 <listitem><para>Pager to use when
 447                                 <option>--no-pager</option> is not given;
 448                                 overrides <varname>$PAGER</varname>.  Setting
 449                                 this to an empty string or the value
 450                                 <literal>cat</literal> is equivalent to passing
 451                                 <option>--no-pager</option>.</para></listitem>
 452                         </varlistentry>
 453                 </variablelist>
 454         </refsect1>
 455
 456         <refsect1>
 457                 <title>Examples</title>
 458
 459                 <para>Without arguments all collected logs are shown
 460                 unfiltered:</para>
 461
 462                 <programlisting>journalctl</programlisting>
 463
 464                 <para>With one match specified all entries with a field matching the expression are shown:</para>
 465
 466                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
 467
 468                 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
 469
 470                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
 471
 472                 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
 473
 474                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
 475
 476                 <para>If the separator "<literal>+</literal>" is used
 477                 two expressions may be combined in a logical OR. The
 478                 following will show all messages from the Avahi
 479                 service process with the PID 28097 plus all messages
 480                 from the D-Bus service (from any of its
 481                 processes):</para>
 482
 483                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
 484
 485                 <para>Show all logs generated by the D-Bus executable:</para>
 486
 487                 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
 488
 489                 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
 490
 491                 <programlisting>journalctl /dev/sda</programlisting>
 492
 493         </refsect1>
 494
 495         <refsect1>
 496                 <title>See Also</title>
 497                 <para>
 498                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 499                         <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 500                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 501                         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 502                         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 503                 </para>
 504         </refsect1>
 505
 506 </refentry>