man/journalctl.xml

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   8   Copyright 2012 Lennart Poettering
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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">MATCH</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 a match argument is passed the output is
  70                 filtered accordingly. A match is in the format
  71                 <literal>FIELD=VALUE</literal>,
  72                 e.g. <literal>_SYSTEMD_UNIT=httpd.service</literal>. See
  73                 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
  74                 for a list of well-known fields.</para>
  75
  76                 <para>Output is interleaved from all accessible
  77                 journal files, whether they are rotated or currently
  78                 being written, and regardless whether they belong to the
  79                 system itself or are accessible user journals.</para>
  80
  81                 <para>All users are granted access to their private
  82                 per-user journals. However, by default only root and
  83                 users who are members of the <literal>adm</literal>
  84                 group get access to the system journal and the
  85                 journals of other users.</para>
  86         </refsect1>
  87
  88         <refsect1>
  89                 <title>Options</title>
  90
  91                 <para>The following options are understood:</para>
  92
  93                 <variablelist>
  94                         <varlistentry>
  95                                 <term><option>--help</option></term>
  96                                 <term><option>-h</option></term>
  97
  98                                 <listitem><para>Prints a short help
  99                                 text and exits.</para></listitem>
 100                         </varlistentry>
 101
 102                         <varlistentry>
 103                                 <term><option>--version</option></term>
 104
 105                                 <listitem><para>Prints a short version
 106                                 string and exits.</para></listitem>
 107                         </varlistentry>
 108
 109                         <varlistentry>
 110                                 <term><option>--no-pager</option></term>
 111
 112                                 <listitem><para>Do not pipe output into a
 113                                 pager.</para></listitem>
 114                         </varlistentry>
 115
 116                         <varlistentry>
 117                                 <term><option>--all</option></term>
 118                                 <term><option>-a</option></term>
 119
 120                                 <listitem><para>Show all fields in
 121                                 full, even if they include unprintable
 122                                 characters or are very
 123                                 long.</para></listitem>
 124                         </varlistentry>
 125
 126                         <varlistentry>
 127                                 <term><option>--follow</option></term>
 128                                 <term><option>-f</option></term>
 129
 130                                 <listitem><para>Show only most recent
 131                                 journal entries, and continously print
 132                                 new entries as they are appended to
 133                                 the journal.</para></listitem>
 134                         </varlistentry>
 135
 136                         <varlistentry>
 137                                 <term><option>--lines=</option></term>
 138                                 <term><option>-n</option></term>
 139
 140                                 <listitem><para>Controls the number of
 141                                 journal lines to show, counting from
 142                                 the most recent ones. Takes a positive
 143                                 integer argument. In follow mode
 144                                 defaults to 10, otherwise is unset
 145                                 thus not limiting how many lines are
 146                                 shown.</para></listitem>
 147                         </varlistentry>
 148
 149                         <varlistentry>
 150                                 <term><option>--no-tail</option></term>
 151
 152                                 <listitem><para>Show all stored output
 153                                 lines, even in follow mode. Undoes the
 154                                 effect of
 155                                 <option>--lines=</option>.</para></listitem>
 156                         </varlistentry>
 157
 158                         <varlistentry>
 159                                 <term><option>--output=</option></term>
 160                                 <term><option>-o</option></term>
 161
 162                                 <listitem><para>Controls the
 163                                 formatting of the journal entries that are
 164                                 shown. Takes one of
 165                                 <literal>short</literal>,
 166                                 <literal>short-monotonic</literal>,
 167                                 <literal>verbose</literal>,
 168                                 <literal>export</literal>,
 169                                 <literal>json</literal>,
 170                                 <literal>cat</literal>. <literal>short</literal>
 171                                 is the default and generates an output
 172                                 that is mostly identical to the
 173                                 formatting of classic syslog log
 174                                 files, showing one line per journal
 175                                 entry. <literal>short-monotonic</literal>
 176                                 is very similar but shows monotonic
 177                                 timestamps instead of wallclock
 178                                 timestamps. <literal>verbose</literal>
 179                                 shows the full structered entry items
 180                                 with all
 181                                 fiels. <literal>export</literal>
 182                                 serializes the journal into a binary
 183                                 (but mostly text-based) stream
 184                                 suitable for backups and network
 185                                 transfer. <literal>json</literal>
 186                                 formats entries as JSON data
 187                                 structures. <literal>cat</literal>
 188                                 generates a very terse output only
 189                                 showing the actual message of each
 190                                 journal entry with no meta data, not
 191                                 even a timestamp.</para></listitem>
 192                         </varlistentry>
 193
 194                         <varlistentry>
 195                                 <term><option>--quiet</option></term>
 196                                 <term><option>-q</option></term>
 197
 198                                 <listitem><para>Suppresses any warning
 199                                 message regarding inaccessable system
 200                                 journals when run as normal
 201                                 user.</para></listitem>
 202                         </varlistentry>
 203
 204                         <varlistentry>
 205                                 <term><option>--local</option></term>
 206                                 <term><option>-l</option></term>
 207
 208                                 <listitem><para>Show only locally
 209                                 generated messages.</para></listitem>
 210                         </varlistentry>
 211
 212                         <varlistentry>
 213                                 <term><option>--this-boot</option></term>
 214                                 <term><option>-b</option></term>
 215
 216                                 <listitem><para>Show data only from
 217                                 current boot.</para></listitem>
 218                         </varlistentry>
 219
 220                         <varlistentry>
 221                                 <term><option>--directory=</option></term>
 222                                 <term><option>-D</option></term>
 223
 224                                 <listitem><para>Takes an absolute
 225                                 directory path as argument. If
 226                                 specified will opearte on the
 227                                 specified journal directory instead of
 228                                 the default runtime and system journal
 229                                 paths.</para></listitem>
 230                         </varlistentry>
 231
 232                         <varlistentry>
 233                                 <term><option>--new-id128</option></term>
 234
 235                                 <listitem><para>Instead of showing
 236                                 journal contents generate a new 128
 237                                 bit ID suitable for identifying
 238                                 messages. This is intended for usage
 239                                 by developers who need a new
 240                                 identifier for a new message they
 241                                 introduce and want to make
 242                                 recognizable. Will print the new ID in
 243                                 three different formats which can be
 244                                 copied into source code or
 245                                 similar.</para></listitem>
 246                         </varlistentry>
 247
 248                 </variablelist>
 249         </refsect1>
 250
 251         <refsect1>
 252                 <title>Exit status</title>
 253
 254                 <para>On success 0 is returned, a non-zero failure
 255                 code otherwise.</para>
 256         </refsect1>
 257
 258         <refsect1>
 259                 <title>Environment</title>
 260
 261                 <variablelist>
 262                         <varlistentry>
 263                                 <term><varname>$SYSTEMD_PAGER</varname></term>
 264                                 <listitem><para>Pager to use when
 265                                 <option>--no-pager</option> is not given;
 266                                 overrides <varname>$PAGER</varname>.  Setting
 267                                 this to an empty string or the value
 268                                 <literal>cat</literal> is equivalent to passing
 269                                 <option>--no-pager</option>.</para></listitem>
 270                         </varlistentry>
 271                 </variablelist>
 272         </refsect1>
 273
 274         <refsect1>
 275                 <title>See Also</title>
 276                 <para>
 277                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 278                         <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 279                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 280                         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 281                         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 282                 </para>
 283         </refsect1>
 284
 285 </refentry>