man/journalctl.xml

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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
  60                 used to query the contents of the
  61                 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  62                 journal.</para>
  63
  64                 <para>If called without parameter will show the full
  65                 contents of the journal, starting with the oldest
  66                 entry collected.</para>
  67
  68                 <para>If a match argument is passed the output is
  69                 filtered accordingly. A match is in the format
  70                 <literal>FIELD=VALUE</literal>,
  71                 e.g. <literal>_SYSTEMD_UNIT=httpd.service</literal>. See
  72                 <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
  73                 for a list of well-known fields.</para>
  74
  75                 <para>Output is interleaved from all accessible
  76                 journal files, whether they are rotated or currently
  77                 being written, and regardless whether they belong to the
  78                 system itself or are accessible user journals.</para>
  79
  80                 <para>All users are granted access to their private
  81                 per-user journals. However, by default only root and
  82                 users who are members of the <literal>adm</literal>
  83                 group get access to the system journal and the
  84                 journals of other users.</para>
  85         </refsect1>
  86
  87         <refsect1>
  88                 <title>Options</title>
  89
  90                 <para>The following options are understood:</para>
  91
  92                 <variablelist>
  93                         <varlistentry>
  94                                 <term><option>--help</option></term>
  95                                 <term><option>-h</option></term>
  96
  97                                 <listitem><para>Prints a short help
  98                                 text and exits.</para></listitem>
  99                         </varlistentry>
 100
 101                         <varlistentry>
 102                                 <term><option>--version</option></term>
 103
 104                                 <listitem><para>Prints a short version
 105                                 string and exits.</para></listitem>
 106                         </varlistentry>
 107
 108                         <varlistentry>
 109                                 <term><option>--no-pager</option></term>
 110
 111                                 <listitem><para>Do not pipe output into a
 112                                 pager.</para></listitem>
 113                         </varlistentry>
 114
 115                         <varlistentry>
 116                                 <term><option>--all</option></term>
 117                                 <term><option>-a</option></term>
 118
 119                                 <listitem><para>Show all fields in
 120                                 full, even if they include unprintable
 121                                 characters or are very
 122                                 long.</para></listitem>
 123                         </varlistentry>
 124
 125                         <varlistentry>
 126                                 <term><option>--follow</option></term>
 127                                 <term><option>-f</option></term>
 128
 129                                 <listitem><para>Show only most recent
 130                                 journal entries, and continously print
 131                                 new entries as they are appended to
 132                                 the journal.</para></listitem>
 133                         </varlistentry>
 134
 135                         <varlistentry>
 136                                 <term><option>--lines=</option></term>
 137                                 <term><option>-n</option></term>
 138
 139                                 <listitem><para>Controls the number of
 140                                 journal lines to show, counting from
 141                                 the most recent ones. Takes a positive
 142                                 integer argument. In follow mode
 143                                 defaults to 10, otherwise is unset
 144                                 thus not limiting how many lines are
 145                                 shown.</para></listitem>
 146                         </varlistentry>
 147
 148                         <varlistentry>
 149                                 <term><option>--no-tail</option></term>
 150
 151                                 <listitem><para>Show all stored output
 152                                 lines, even in follow mode. Undoes the
 153                                 effect of
 154                                 <option>--lines=</option>.</para></listitem>
 155                         </varlistentry>
 156
 157                         <varlistentry>
 158                                 <term><option>--output=</option></term>
 159                                 <term><option>-o</option></term>
 160
 161                                 <listitem><para>Controls the
 162                                 formatting of the journal entries that are
 163                                 shown. Takes one of
 164                                 <literal>short</literal>,
 165                                 <literal>short-monotonic</literal>,
 166                                 <literal>verbose</literal>,
 167                                 <literal>export</literal>,
 168                                 <literal>json</literal>,
 169                                 <literal>cat</literal>. <literal>short</literal>
 170                                 is the default and generates an output
 171                                 that is mostly identical to the
 172                                 formatting of classic syslog log
 173                                 files, showing one line per journal
 174                                 entry. <literal>short-monotonic</literal>
 175                                 is very similar but shows monotonic
 176                                 timestamps instead of wallclock
 177                                 timestamps. <literal>verbose</literal>
 178                                 shows the full structered entry items
 179                                 with all
 180                                 fiels. <literal>export</literal>
 181                                 serializes the journal into a binary
 182                                 (but mostly text-based) stream
 183                                 suitable for backups and network
 184                                 transfer. <literal>json</literal>
 185                                 formats entries as JSON data
 186                                 structures. <literal>cat</literal>
 187                                 generates a very terse output only
 188                                 showing the actual message of each
 189                                 journal entry with no meta data, not
 190                                 even a timestamp.</para></listitem>
 191                         </varlistentry>
 192
 193                         <varlistentry>
 194                                 <term><option>--quiet</option></term>
 195                                 <term><option>-q</option></term>
 196
 197                                 <listitem><para>Suppresses any warning
 198                                 message regarding inaccessable system
 199                                 journals when run as normal
 200                                 user.</para></listitem>
 201                         </varlistentry>
 202
 203                         <varlistentry>
 204                                 <term><option>--local</option></term>
 205                                 <term><option>-l</option></term>
 206
 207                                 <listitem><para>Show only locally
 208                                 generated messages.</para></listitem>
 209                         </varlistentry>
 210
 211                         <varlistentry>
 212                                 <term><option>--new-id128</option></term>
 213
 214                                 <listitem><para>Instead of showing
 215                                 journal contents generate a new 128
 216                                 bit ID suitable for identifying
 217                                 messages. This is intended for usage
 218                                 by developers who need a new
 219                                 identifier for a new message they
 220                                 introduce and want to make
 221                                 recognizable. Will print the new ID in
 222                                 three different formats which can be
 223                                 copied into source code or
 224                                 similar.</para></listitem>
 225                         </varlistentry>
 226
 227                 </variablelist>
 228         </refsect1>
 229
 230         <refsect1>
 231                 <title>Exit status</title>
 232
 233                 <para>On success 0 is returned, a non-zero failure
 234                 code otherwise.</para>
 235         </refsect1>
 236
 237         <refsect1>
 238                 <title>Environment</title>
 239
 240                 <variablelist>
 241                         <varlistentry>
 242                                 <term><varname>$SYSTEMD_PAGER</varname></term>
 243                                 <listitem><para>Pager to use when
 244                                 <option>--no-pager</option> is not given;
 245                                 overrides <varname>$PAGER</varname>.  Setting
 246                                 this to an empty string or the value
 247                                 <literal>cat</literal> is equivalent to passing
 248                                 <option>--no-pager</option>.</para></listitem>
 249                         </varlistentry>
 250                 </variablelist>
 251         </refsect1>
 252
 253         <refsect1>
 254                 <title>See Also</title>
 255                 <para>
 256                         <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 257                         <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 258                         <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 259                         <citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 260                 </para>
 261         </refsect1>
 262
 263 </refentry>