man/journalctl.xml

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   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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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 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 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. Takes a positive
 165                                 integer argument. In follow mode
 166                                 defaults to 10, otherwise is unset
 167                                 thus not limiting how many lines are
 168                                 shown.</para></listitem>
 169                         </varlistentry>
 170
 171                         <varlistentry>
 172                                 <term><option>--no-tail</option></term>
 173
 174                                 <listitem><para>Show all stored output
 175                                 lines, even in follow mode. Undoes the
 176                                 effect of
 177                                 <option>--lines=</option>.</para></listitem>
 178                         </varlistentry>
 179
 180                         <varlistentry>
 181                                 <term><option>--output=</option></term>
 182                                 <term><option>-o</option></term>
 183
 184                                 <listitem><para>Controls the
 185                                 formatting of the journal entries that
 186                                 are shown. Takes one of
 187                                 <literal>short</literal>,
 188                                 <literal>short-monotonic</literal>,
 189                                 <literal>verbose</literal>,
 190                                 <literal>export</literal>,
 191                                 <literal>json</literal>,
 192                                 <literal>json-pretty</literal>,
 193                                 <literal>cat</literal>. <literal>short</literal>
 194                                 is the default and generates an output
 195                                 that is mostly identical to the
 196                                 formatting of classic syslog log
 197                                 files, showing one line per journal
 198                                 entry. <literal>short-monotonic</literal>
 199                                 is very similar but shows monotonic
 200                                 timestamps instead of wallclock
 201                                 timestamps. <literal>verbose</literal>
 202                                 shows the full structured entry items
 203                                 with all
 204                                 fields. <literal>export</literal>
 205                                 serializes the journal into a binary
 206                                 (but mostly text-based) stream
 207                                 suitable for backups and network
 208                                 transfer (see <ulink
 209                                 url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal
 210                                 Export Format</ulink> for more
 211                                 information). <literal>json</literal>
 212                                 formats entries as JSON data
 213                                 structures, one per
 214                                 line. <literal>json-pretty</literal>
 215                                 also formats entries as JSON data
 216                                 structures, but formats them in
 217                                 multiple lines in order to make them
 218                                 more readable for
 219                                 humans. <literal>cat</literal>
 220                                 generates a very terse output only
 221                                 showing the actual message of each
 222                                 journal entry with no meta data, not
 223                                 even a timestamp.</para></listitem>
 224                         </varlistentry>
 225
 226                         <varlistentry>
 227                                 <term><option>--quiet</option></term>
 228                                 <term><option>-q</option></term>
 229
 230                                 <listitem><para>Suppresses any warning
 231                                 message regarding inaccessible system
 232                                 journals when run as normal
 233                                 user.</para></listitem>
 234                         </varlistentry>
 235
 236                         <varlistentry>
 237                                 <term><option>--merge</option></term>
 238                                 <term><option>-m</option></term>
 239
 240                                 <listitem><para>Show entries
 241                                 interleaved from all available
 242                                 journals, including remote
 243                                 ones.</para></listitem>
 244                         </varlistentry>
 245
 246                         <varlistentry>
 247                                 <term><option>--this-boot</option></term>
 248                                 <term><option>-b</option></term>
 249
 250                                 <listitem><para>Show data only from
 251                                 current boot.</para></listitem>
 252                         </varlistentry>
 253
 254                         <varlistentry>
 255                                 <term><option>--directory=</option></term>
 256                                 <term><option>-D</option></term>
 257
 258                                 <listitem><para>Takes an absolute
 259                                 directory path as argument. If
 260                                 specified will operate on the
 261                                 specified journal directory instead of
 262                                 the default runtime and system journal
 263                                 paths.</para></listitem>
 264                         </varlistentry>
 265
 266                         <varlistentry>
 267                                 <term><option>-p</option></term>
 268                                 <term><option>--priority=</option></term>
 269
 270                                 <listitem><para>Filter output by
 271                                 message priorities or priority
 272                                 ranges. Takes either a single numeric
 273                                 or textual log level (i.e. between
 274                                 0/<literal>emerg</literal> and
 275                                 7/<literal>debug</literal>), or a
 276                                 range of numeric/text log levels in
 277                                 the form FROM..TO. The log levels are
 278                                 the usual syslog log levels as
 279                                 documented in
 280                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 281                                 i.e. <literal>emerg</literal> (0),
 282                                 <literal>alert</literal> (1),
 283                                 <literal>crit</literal> (2),
 284                                 <literal>err</literal> (3),
 285                                 <literal>warning</literal> (4),
 286                                 <literal>notice</literal> (5),
 287                                 <literal>info</literal> (6),
 288                                 <literal>debug</literal> (7). If a
 289                                 single log level is specified all
 290                                 messages with this log levels or a
 291                                 lower (hence more important) log level
 292                                 are shown. If a range is specified all
 293                                 messages within the range are shown,
 294                                 including both the start and the end
 295                                 value of the range.</para></listitem>
 296                         </varlistentry>
 297
 298                         <varlistentry>
 299                                 <term><option>--new-id128</option></term>
 300
 301                                 <listitem><para>Instead of showing
 302                                 journal contents generate a new 128
 303                                 bit ID suitable for identifying
 304                                 messages. This is intended for usage
 305                                 by developers who need a new
 306                                 identifier for a new message they
 307                                 introduce and want to make
 308                                 recognizable. Will print the new ID in
 309                                 three different formats which can be
 310                                 copied into source code or
 311                                 similar.</para></listitem>
 312                         </varlistentry>
 313
 314                         <varlistentry>
 315                                 <term><option>--header</option></term>
 316
 317                                 <listitem><para>Instead of showing
 318                                 journal contents show internal header
 319                                 information of the journal fiels
 320                                 accessed.</para></listitem>
 321                         </varlistentry>
 322
 323                         <varlistentry>
 324                                 <term><option>--setup-keys</option></term>
 325
 326                                 <listitem><para>Instead of showing
 327                                 journal contents generate a new key
 328                                 pair for Forward Secure Sealing
 329                                 (FSS). This will generate a sealing
 330                                 key and a verification key. The
 331                                 sealing key is stored in the journal
 332                                 data directory and shall remain on the
 333                                 host. The verification key should be
 334                                 stored externally.</para></listitem>
 335                         </varlistentry>
 336
 337                         <varlistentry>
 338                                 <term><option>--interval=</option></term>
 339
 340                                 <listitem><para>Specifies the change
 341                                 interval for the sealing key, when
 342                                 generating an FSS key pair with
 343                                 <option>--setup-keys</option>. Shorter
 344                                 intervals increase CPU consumption but
 345                                 shorten the time range of
 346                                 undetectable journal
 347                                 alterations. Defaults to
 348                                 15min.</para></listitem>
 349                         </varlistentry>
 350
 351                         <varlistentry>
 352                                 <term><option>--verify</option></term>
 353
 354                                 <listitem><para>Check the journal file
 355                                 for internal consistency. If the
 356                                 file has been generated with FSS
 357                                 enabled, and the FSS verification key
 358                                 has been specified with
 359                                 <option>--verify-key=</option>
 360                                 authenticity of the journal file is
 361                                 verified.</para></listitem>
 362                         </varlistentry>
 363
 364                         <varlistentry>
 365                                 <term><option>--verify-key=</option></term>
 366
 367                                 <listitem><para>Specifies the FSS
 368                                 verification key to use for the
 369                                 <option>--verify</option>
 370                                 operation.</para></listitem>
 371                         </varlistentry>
 372
 373                 </variablelist>
 374         </refsect1>
 375
 376         <refsect1>
 377                 <title>Exit status</title>
 378
 379                 <para>On success 0 is returned, a non-zero failure
 380                 code otherwise.</para>
 381         </refsect1>
 382
 383         <refsect1>
 384                 <title>Environment</title>
 385
 386                 <variablelist>
 387                         <varlistentry>
 388                                 <term><varname>$SYSTEMD_PAGER</varname></term>
 389                                 <listitem><para>Pager to use when
 390                                 <option>--no-pager</option> is not given;
 391                                 overrides <varname>$PAGER</varname>.  Setting
 392                                 this to an empty string or the value
 393                                 <literal>cat</literal> is equivalent to passing
 394                                 <option>--no-pager</option>.</para></listitem>
 395                         </varlistentry>
 396                 </variablelist>
 397         </refsect1>
 398
 399         <refsect1>
 400                 <title>Examples</title>
 401
 402                 <para>Without arguments all collected logs are shown
 403                 unfiltered:</para>
 404
 405                 <programlisting>journalctl</programlisting>
 406
 407                 <para>With one match specified all entries with a field matching the expression are shown:</para>
 408
 409                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
 410
 411                 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
 412
 413                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
 414
 415                 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
 416
 417                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
 418
 419                 <para>If the separator "<literal>+</literal>" is used
 420                 two expression may be combined in a logical OR. The
 421                 following will show all messages from the Avahi
 422                 service process with the PID 28097 plus all messages
 423                 from the D-Bus service (from any of its
 424                 processes):</para>
 425
 426                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
 427
 428                 <para>Show all logs generated by the D-Bus executable:</para>
 429
 430                 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
 431
 432                 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
 433
 434                 <programlisting>journalctl /dev/sda</programlisting>
 435
 436         </refsect1>
 437
 438         <refsect1>
 439                 <title>See Also</title>
 440                 <para>
 441                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 442                         <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 443                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 444                         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 445                         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 446                 </para>
 447         </refsect1>
 448
 449 </refentry>