man/journalctl.xml

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   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>cat</literal>. <literal>short</literal>
 197                                 is the default and generates an output
 198                                 that is mostly identical to the
 199                                 formatting of classic syslog log
 200                                 files, showing one line per journal
 201                                 entry. <literal>short-monotonic</literal>
 202                                 is very similar but shows monotonic
 203                                 timestamps instead of wallclock
 204                                 timestamps. <literal>verbose</literal>
 205                                 shows the full structured entry items
 206                                 with all
 207                                 fields. <literal>export</literal>
 208                                 serializes the journal into a binary
 209                                 (but mostly text-based) stream
 210                                 suitable for backups and network
 211                                 transfer (see <ulink
 212                                 url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal
 213                                 Export Format</ulink> for more
 214                                 information). <literal>json</literal>
 215                                 formats entries as JSON data
 216                                 structures, one per
 217                                 line. <literal>json-pretty</literal>
 218                                 also formats entries as JSON data
 219                                 structures, but formats them in
 220                                 multiple lines in order to make them
 221                                 more readable for
 222                                 humans. <literal>cat</literal>
 223                                 generates a very terse output only
 224                                 showing the actual message of each
 225                                 journal entry with no meta data, not
 226                                 even a timestamp.</para></listitem>
 227                         </varlistentry>
 228
 229                         <varlistentry>
 230                                 <term><option>--quiet</option></term>
 231                                 <term><option>-q</option></term>
 232
 233                                 <listitem><para>Suppresses any warning
 234                                 message regarding inaccessible system
 235                                 journals when run as normal
 236                                 user.</para></listitem>
 237                         </varlistentry>
 238
 239                         <varlistentry>
 240                                 <term><option>--merge</option></term>
 241                                 <term><option>-m</option></term>
 242
 243                                 <listitem><para>Show entries
 244                                 interleaved from all available
 245                                 journals, including remote
 246                                 ones.</para></listitem>
 247                         </varlistentry>
 248
 249                         <varlistentry>
 250                                 <term><option>--this-boot</option></term>
 251                                 <term><option>-b</option></term>
 252
 253                                 <listitem><para>Show data only from
 254                                 current boot.</para></listitem>
 255                         </varlistentry>
 256
 257                         <varlistentry>
 258                                 <term><option>--cursor=</option></term>
 259                                 <term><option>-c</option></term>
 260
 261                                 <listitem><para>Jump to the location
 262                                 in the journal specified by the passed
 263                                 cursor.</para></listitem>
 264                         </varlistentry>
 265
 266                         <varlistentry>
 267                                 <term><option>--directory=</option></term>
 268                                 <term><option>-D</option></term>
 269
 270                                 <listitem><para>Takes an absolute
 271                                 directory path as argument. If
 272                                 specified journalctl will operate on the
 273                                 specified journal directory instead of
 274                                 the default runtime and system journal
 275                                 paths.</para></listitem>
 276                         </varlistentry>
 277
 278                         <varlistentry>
 279                                 <term><option>-p</option></term>
 280                                 <term><option>--priority=</option></term>
 281
 282                                 <listitem><para>Filter output by
 283                                 message priorities or priority
 284                                 ranges. Takes either a single numeric
 285                                 or textual log level (i.e. between
 286                                 0/<literal>emerg</literal> and
 287                                 7/<literal>debug</literal>), or a
 288                                 range of numeric/text log levels in
 289                                 the form FROM..TO. The log levels are
 290                                 the usual syslog log levels as
 291                                 documented in
 292                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 293                                 i.e. <literal>emerg</literal> (0),
 294                                 <literal>alert</literal> (1),
 295                                 <literal>crit</literal> (2),
 296                                 <literal>err</literal> (3),
 297                                 <literal>warning</literal> (4),
 298                                 <literal>notice</literal> (5),
 299                                 <literal>info</literal> (6),
 300                                 <literal>debug</literal> (7). If a
 301                                 single log level is specified all
 302                                 messages with this log level or a
 303                                 lower (hence more important) log level
 304                                 are shown. If a range is specified all
 305                                 messages within the range are shown,
 306                                 including both the start and the end
 307                                 value of the range.</para></listitem>
 308                         </varlistentry>
 309
 310                         <varlistentry>
 311                                 <term><option>--new-id128</option></term>
 312
 313                                 <listitem><para>Instead of showing
 314                                 journal contents generate a new 128
 315                                 bit ID suitable for identifying
 316                                 messages. This is intended for usage
 317                                 by developers who need a new
 318                                 identifier for a new message they
 319                                 introduce and want to make
 320                                 recognizable. Will print the new ID in
 321                                 three different formats which can be
 322                                 copied into source code or
 323                                 similar.</para></listitem>
 324                         </varlistentry>
 325
 326                         <varlistentry>
 327                                 <term><option>--header</option></term>
 328
 329                                 <listitem><para>Instead of showing
 330                                 journal contents show internal header
 331                                 information of the journal fields
 332                                 accessed.</para></listitem>
 333                         </varlistentry>
 334
 335                         <varlistentry>
 336                                 <term><option>--disk-usage</option></term>
 337
 338                                 <listitem><para>Shows the current disk
 339                                 usage of all
 340                                 journal files.</para></listitem>
 341                         </varlistentry>
 342
 343                         <varlistentry>
 344                                 <term><option>--setup-keys</option></term>
 345
 346                                 <listitem><para>Instead of showing
 347                                 journal contents generate a new key
 348                                 pair for Forward Secure Sealing
 349                                 (FSS). This will generate a sealing
 350                                 key and a verification key. The
 351                                 sealing key is stored in the journal
 352                                 data directory and shall remain on the
 353                                 host. The verification key should be
 354                                 stored externally.</para></listitem>
 355                         </varlistentry>
 356
 357                         <varlistentry>
 358                                 <term><option>--interval=</option></term>
 359
 360                                 <listitem><para>Specifies the change
 361                                 interval for the sealing key, when
 362                                 generating an FSS key pair with
 363                                 <option>--setup-keys</option>. Shorter
 364                                 intervals increase CPU consumption but
 365                                 shorten the time range of
 366                                 undetectable journal
 367                                 alterations. Defaults to
 368                                 15min.</para></listitem>
 369                         </varlistentry>
 370
 371                         <varlistentry>
 372                                 <term><option>--verify</option></term>
 373
 374                                 <listitem><para>Check the journal file
 375                                 for internal consistency. If the
 376                                 file has been generated with FSS
 377                                 enabled, and the FSS verification key
 378                                 has been specified with
 379                                 <option>--verify-key=</option>
 380                                 authenticity of the journal file is
 381                                 verified.</para></listitem>
 382                         </varlistentry>
 383
 384                         <varlistentry>
 385                                 <term><option>--verify-key=</option></term>
 386
 387                                 <listitem><para>Specifies the FSS
 388                                 verification key to use for the
 389                                 <option>--verify</option>
 390                                 operation.</para></listitem>
 391                         </varlistentry>
 392
 393                 </variablelist>
 394         </refsect1>
 395
 396         <refsect1>
 397                 <title>Exit status</title>
 398
 399                 <para>On success 0 is returned, a non-zero failure
 400                 code otherwise.</para>
 401         </refsect1>
 402
 403         <refsect1>
 404                 <title>Environment</title>
 405
 406                 <variablelist>
 407                         <varlistentry>
 408                                 <term><varname>$SYSTEMD_PAGER</varname></term>
 409                                 <listitem><para>Pager to use when
 410                                 <option>--no-pager</option> is not given;
 411                                 overrides <varname>$PAGER</varname>.  Setting
 412                                 this to an empty string or the value
 413                                 <literal>cat</literal> is equivalent to passing
 414                                 <option>--no-pager</option>.</para></listitem>
 415                         </varlistentry>
 416                 </variablelist>
 417         </refsect1>
 418
 419         <refsect1>
 420                 <title>Examples</title>
 421
 422                 <para>Without arguments all collected logs are shown
 423                 unfiltered:</para>
 424
 425                 <programlisting>journalctl</programlisting>
 426
 427                 <para>With one match specified all entries with a field matching the expression are shown:</para>
 428
 429                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
 430
 431                 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
 432
 433                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
 434
 435                 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
 436
 437                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
 438
 439                 <para>If the separator "<literal>+</literal>" is used
 440                 two expressions may be combined in a logical OR. The
 441                 following will show all messages from the Avahi
 442                 service process with the PID 28097 plus all messages
 443                 from the D-Bus service (from any of its
 444                 processes):</para>
 445
 446                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
 447
 448                 <para>Show all logs generated by the D-Bus executable:</para>
 449
 450                 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
 451
 452                 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
 453
 454                 <programlisting>journalctl /dev/sda</programlisting>
 455
 456         </refsect1>
 457
 458         <refsect1>
 459                 <title>See Also</title>
 460                 <para>
 461                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 462                         <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 463                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 464                         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 465                         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 466                 </para>
 467         </refsect1>
 468
 469 </refentry>