man/journalctl.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
   3         "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4
   5 <!--
   6   This file is part of systemd.
   7
   8   Copyright 2012 Lennart Poettering
   9
  10   systemd is free software; you can redistribute it and/or modify it
  11   under the terms of the GNU Lesser General Public License as published by
  12   the Free Software Foundation; either version 2.1 of the License, or
  13   (at your option) any later version.
  14
  15   systemd is distributed in the hope that it will be useful, but
  16   WITHOUT ANY WARRANTY; without even the implied warranty of
  17   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  18   Lesser General Public License for more details.
  19
  20   You should have received a copy of the GNU Lesser General Public License
  21   along with systemd; If not, see <http://www.gnu.org/licenses/>.
  22 -->
  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>--local</option></term>
 238                                 <term><option>-l</option></term>
 239
 240                                 <listitem><para>Show only locally
 241                                 generated messages.</para></listitem>
 242                         </varlistentry>
 243
 244                         <varlistentry>
 245                                 <term><option>--this-boot</option></term>
 246                                 <term><option>-b</option></term>
 247
 248                                 <listitem><para>Show data only from
 249                                 current boot.</para></listitem>
 250                         </varlistentry>
 251
 252                         <varlistentry>
 253                                 <term><option>--directory=</option></term>
 254                                 <term><option>-D</option></term>
 255
 256                                 <listitem><para>Takes an absolute
 257                                 directory path as argument. If
 258                                 specified will operate on the
 259                                 specified journal directory instead of
 260                                 the default runtime and system journal
 261                                 paths.</para></listitem>
 262                         </varlistentry>
 263
 264                         <varlistentry>
 265                                 <term><option>-p</option></term>
 266                                 <term><option>--priority=</option></term>
 267
 268                                 <listitem><para>Filter output by
 269                                 message priorities or priority
 270                                 ranges. Takes either a single numeric
 271                                 or textual log level (i.e. between
 272                                 0/<literal>emerg</literal> and
 273                                 7/<literal>debug</literal>), or a
 274                                 range of numeric/text log levels in
 275                                 the form FROM..TO. The log levels are
 276                                 the usual syslog log levels as
 277                                 documented in
 278                                 <citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
 279                                 i.e. <literal>emerg</literal> (0),
 280                                 <literal>alert</literal> (1),
 281                                 <literal>crit</literal> (2),
 282                                 <literal>err</literal> (3),
 283                                 <literal>warning</literal> (4),
 284                                 <literal>notice</literal> (5),
 285                                 <literal>info</literal> (6),
 286                                 <literal>debug</literal> (7). If a
 287                                 single log level is specified all
 288                                 messages with this log levels or a
 289                                 lower (hence more important) log level
 290                                 are shown. If a range is specified all
 291                                 messages within the range are shown,
 292                                 including both the start and the end
 293                                 value of the range.</para></listitem>
 294                         </varlistentry>
 295
 296                         <varlistentry>
 297                                 <term><option>--new-id128</option></term>
 298
 299                                 <listitem><para>Instead of showing
 300                                 journal contents generate a new 128
 301                                 bit ID suitable for identifying
 302                                 messages. This is intended for usage
 303                                 by developers who need a new
 304                                 identifier for a new message they
 305                                 introduce and want to make
 306                                 recognizable. Will print the new ID in
 307                                 three different formats which can be
 308                                 copied into source code or
 309                                 similar.</para></listitem>
 310                         </varlistentry>
 311
 312                         <varlistentry>
 313                                 <term><option>--header</option></term>
 314
 315                                 <listitem><para>Instead of showing
 316                                 journal contents show internal header
 317                                 information of the journal fiels
 318                                 accessed.</para></listitem>
 319                         </varlistentry>
 320
 321                         <varlistentry>
 322                                 <term><option>--setup-keys</option></term>
 323
 324                                 <listitem><para>Instead of showing
 325                                 journal contents generate a new key
 326                                 pair for Forward Secure Sealing
 327                                 (FSS). This will generate a sealing
 328                                 key and a verification key. The
 329                                 sealing key is stored in the journal
 330                                 data directory and shall remain on the
 331                                 host. The verification key should be
 332                                 stored externally.</para></listitem>
 333                         </varlistentry>
 334
 335                         <varlistentry>
 336                                 <term><option>--interval=</option></term>
 337
 338                                 <listitem><para>Specifies the change
 339                                 interval for the sealing key, when
 340                                 generating an FSS key pair with
 341                                 <option>--setup-keys</option>. Shorter
 342                                 intervals increase CPU consumption but
 343                                 shorten the time range of
 344                                 undetectable journal
 345                                 alterations. Defaults to
 346                                 15min.</para></listitem>
 347                         </varlistentry>
 348
 349                         <varlistentry>
 350                                 <term><option>--verify</option></term>
 351
 352                                 <listitem><para>Check the journal file
 353                                 for internal consistency. If the
 354                                 file has been generated with FSS
 355                                 enabled, and the FSS verification key
 356                                 has been specified with
 357                                 <option>--verify-key=</option>
 358                                 authenticity of the journal file is
 359                                 verified.</para></listitem>
 360                         </varlistentry>
 361
 362                         <varlistentry>
 363                                 <term><option>--verify-key=</option></term>
 364
 365                                 <listitem><para>Specifies the FSS
 366                                 verification key to use for the
 367                                 <option>--verify</option>
 368                                 operation.</para></listitem>
 369                         </varlistentry>
 370
 371                 </variablelist>
 372         </refsect1>
 373
 374         <refsect1>
 375                 <title>Exit status</title>
 376
 377                 <para>On success 0 is returned, a non-zero failure
 378                 code otherwise.</para>
 379         </refsect1>
 380
 381         <refsect1>
 382                 <title>Environment</title>
 383
 384                 <variablelist>
 385                         <varlistentry>
 386                                 <term><varname>$SYSTEMD_PAGER</varname></term>
 387                                 <listitem><para>Pager to use when
 388                                 <option>--no-pager</option> is not given;
 389                                 overrides <varname>$PAGER</varname>.  Setting
 390                                 this to an empty string or the value
 391                                 <literal>cat</literal> is equivalent to passing
 392                                 <option>--no-pager</option>.</para></listitem>
 393                         </varlistentry>
 394                 </variablelist>
 395         </refsect1>
 396
 397         <refsect1>
 398                 <title>Examples</title>
 399
 400                 <para>Without arguments all collected logs are shown
 401                 unfiltered:</para>
 402
 403                 <programlisting>journalctl</programlisting>
 404
 405                 <para>With one match specified all entries with a field matching the expression are shown:</para>
 406
 407                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
 408
 409                 <para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
 410
 411                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
 412
 413                 <para>If two matches refer to the same field all entries matching either expression are shown:</para>
 414
 415                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
 416
 417                 <para>If the separator "<literal>+</literal>" is used
 418                 two expression may be combined in a logical OR. The
 419                 following will show all messages from the Avahi
 420                 service process with the PID 28097 plus all messages
 421                 from the D-Bus service (from any of its
 422                 processes):</para>
 423
 424                 <programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
 425
 426                 <para>Show all logs generated by the D-Bus executable:</para>
 427
 428                 <programlisting>journalctl /usr/bin/dbus-daemon</programlisting>
 429
 430                 <para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>
 431
 432                 <programlisting>journalctl /dev/sda</programlisting>
 433
 434         </refsect1>
 435
 436         <refsect1>
 437                 <title>See Also</title>
 438                 <para>
 439                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 440                         <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 441                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 442                         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 443                         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 444                 </para>
 445         </refsect1>
 446
 447 </refentry>