man/systemd-cat.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   SPDX-License-Identifier: LGPL-2.1+
   7 -->
   8
   9 <refentry id="systemd-cat"
  10     xmlns:xi="http://www.w3.org/2001/XInclude">
  11
  12   <refentryinfo>
  13     <title>systemd-cat</title>
  14     <productname>systemd</productname>
  15   </refentryinfo>
  16
  17   <refmeta>
  18     <refentrytitle>systemd-cat</refentrytitle>
  19     <manvolnum>1</manvolnum>
  20   </refmeta>
  21
  22   <refnamediv>
  23     <refname>systemd-cat</refname>
  24     <refpurpose>Connect a pipeline or program's output with the journal</refpurpose>
  25   </refnamediv>
  26
  27   <refsynopsisdiv>
  28     <cmdsynopsis>
  29       <command>systemd-cat <arg choice="opt" rep="repeat">OPTIONS</arg> <arg>COMMAND</arg> <arg choice="opt" rep="repeat">ARGUMENTS</arg></command>
  30     </cmdsynopsis>
  31     <cmdsynopsis>
  32       <command>systemd-cat <arg choice="opt" rep="repeat">OPTIONS</arg></command>
  33     </cmdsynopsis>
  34   </refsynopsisdiv>
  35
  36   <refsect1>
  37     <title>Description</title>
  38
  39     <para><command>systemd-cat</command> may be used to connect the
  40     standard input and output of a process to the journal, or as a
  41     filter tool in a shell pipeline to pass the output the previous
  42     pipeline element generates to the journal.</para>
  43
  44     <para>If no parameter is passed, <command>systemd-cat</command>
  45     will write everything it reads from standard input (stdin) to the
  46     journal.</para>
  47
  48     <para>If parameters are passed, they are executed as command line
  49     with standard output (stdout) and standard error output (stderr)
  50     connected to the journal, so that all it writes is stored in the
  51     journal.</para>
  52   </refsect1>
  53
  54   <refsect1>
  55     <title>Options</title>
  56
  57     <para>The following options are understood:</para>
  58
  59     <variablelist>
  60       <xi:include href="standard-options.xml" xpointer="help" />
  61       <xi:include href="standard-options.xml" xpointer="version" />
  62
  63       <varlistentry>
  64         <term><option>-t</option></term>
  65         <term><option>--identifier=</option></term>
  66
  67         <listitem><para>Specify a short string that is used to
  68         identify the logging tool. If not specified, no identification
  69         string is written to the journal.</para></listitem>
  70       </varlistentry>
  71
  72       <varlistentry>
  73         <term><option>-p</option></term>
  74         <term><option>--priority=</option></term>
  75
  76         <listitem><para>Specify the default priority level for the
  77         logged messages. Pass one of
  78         <literal>emerg</literal>,
  79         <literal>alert</literal>,
  80         <literal>crit</literal>,
  81         <literal>err</literal>,
  82         <literal>warning</literal>,
  83         <literal>notice</literal>,
  84         <literal>info</literal>,
  85         <literal>debug</literal>, or a
  86         value between 0 and 7 (corresponding to the same named
  87         levels). These priority values are the same as defined by
  88         <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
  89         Defaults to <literal>info</literal>. Note that this simply
  90         controls the default, individual lines may be logged with
  91         different levels if they are prefixed accordingly. For details,
  92         see <option>--level-prefix=</option> below.</para></listitem>
  93       </varlistentry>
  94
  95       <varlistentry>
  96         <term><option>--stderr-priority=</option></term>
  97
  98         <listitem><para>Specifies the default priority level for
  99         messages from the process's standard error output (stderr).
 100         Usage of this option is the same as the
 101         <option>--priority=</option> option, above, and both can be
 102         used at once. When both are used, <option>--priority=</option>
 103         will specify the default priority for standard output (stdout).
 104         </para>
 105
 106         <para>If <option>--stderr-priority=</option> is not specified,
 107         messages from stderr will still be logged, with the same
 108         default priority level as stdout.</para>
 109
 110         <para>Also, note that when stdout and stderr use the same
 111         default priority, the messages will be strictly ordered,
 112         because one channel is used for both. When the default priority
 113         differs, two channels are used, and so stdout messages will not
 114         be strictly ordered with respect to stderr messages - though
 115         they will tend to be approximately ordered.</para></listitem>
 116       </varlistentry>
 117
 118       <varlistentry>
 119         <term><option>--level-prefix=</option></term>
 120
 121         <listitem><para>Controls whether lines read are parsed for
 122         syslog priority level prefixes. If enabled (the default), a
 123         line prefixed with a priority prefix such as
 124         <literal>&lt;5&gt;</literal> is logged at priority 5
 125         (<literal>notice</literal>), and similar for the other
 126         priority levels. Takes a boolean argument.</para></listitem>
 127       </varlistentry>
 128
 129     </variablelist>
 130
 131   </refsect1>
 132
 133   <refsect1>
 134     <title>Exit status</title>
 135
 136     <para>On success, 0 is returned, a non-zero failure code
 137     otherwise.</para>
 138   </refsect1>
 139
 140   <refsect1>
 141     <title>Examples</title>
 142
 143     <example>
 144       <title>Invoke a program</title>
 145
 146       <para>This calls <filename noindex='true'>/bin/ls</filename>
 147       with standard output and error connected to the journal:</para>
 148
 149       <programlisting># systemd-cat ls</programlisting>
 150     </example>
 151
 152     <example>
 153       <title>Usage in a shell pipeline</title>
 154
 155       <para>This builds a shell pipeline also invoking
 156       <filename>/bin/ls</filename> and writes the output it generates
 157       to the journal:</para>
 158
 159       <programlisting># ls | systemd-cat</programlisting>
 160     </example>
 161
 162     <para>Even though the two examples have very similar effects the
 163     first is preferable since only one process is running at a time,
 164     and both stdout and stderr are captured while in the second
 165     example, only stdout is captured.</para>
 166   </refsect1>
 167
 168   <refsect1>
 169     <title>See Also</title>
 170     <para>
 171       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 172       <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 173       <citerefentry project='man-pages'><refentrytitle>logger</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 174     </para>
 175   </refsect1>
 176
 177 </refentry>