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