man/systemd-cat.xml

   1 <?xml version='1.0'?> <!--*-nxml-*-->
   2 <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
   3   "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
   4 <!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
   5
   6 <refentry id="systemd-cat"
   7     xmlns:xi="http://www.w3.org/2001/XInclude">
   8
   9   <refentryinfo>
  10     <title>systemd-cat</title>
  11     <productname>systemd</productname>
  12   </refentryinfo>
  13
  14   <refmeta>
  15     <refentrytitle>systemd-cat</refentrytitle>
  16     <manvolnum>1</manvolnum>
  17   </refmeta>
  18
  19   <refnamediv>
  20     <refname>systemd-cat</refname>
  21     <refpurpose>Connect a pipeline or program's output with the journal</refpurpose>
  22   </refnamediv>
  23
  24   <refsynopsisdiv>
  25     <cmdsynopsis>
  26       <command>systemd-cat <arg choice="opt" rep="repeat">OPTIONS</arg> <arg>COMMAND</arg> <arg choice="opt" rep="repeat">ARGUMENTS</arg></command>
  27     </cmdsynopsis>
  28     <cmdsynopsis>
  29       <command>systemd-cat <arg choice="opt" rep="repeat">OPTIONS</arg></command>
  30     </cmdsynopsis>
  31   </refsynopsisdiv>
  32
  33   <refsect1>
  34     <title>Description</title>
  35
  36     <para><command>systemd-cat</command> may be used to connect the
  37     standard input and output of a process to the journal, or as a
  38     filter tool in a shell pipeline to pass the output the previous
  39     pipeline element generates to the journal.</para>
  40
  41     <para>If no parameter is passed, <command>systemd-cat</command>
  42     will write everything it reads from standard input (stdin) to the
  43     journal.</para>
  44
  45     <para>If parameters are passed, they are executed as command line
  46     with standard output (stdout) and standard error output (stderr)
  47     connected to the journal, so that all it writes is stored in the
  48     journal.</para>
  49   </refsect1>
  50
  51   <refsect1>
  52     <title>Options</title>
  53
  54     <para>The following options are understood:</para>
  55
  56     <variablelist>
  57       <xi:include href="standard-options.xml" xpointer="help" />
  58       <xi:include href="standard-options.xml" xpointer="version" />
  59
  60       <varlistentry>
  61         <term><option>-t</option></term>
  62         <term><option>--identifier=</option></term>
  63
  64         <listitem><para>Specify a short string that is used to
  65         identify the logging tool. If not specified, no identification
  66         string is written to the journal.</para></listitem>
  67       </varlistentry>
  68
  69       <varlistentry>
  70         <term><option>-p</option></term>
  71         <term><option>--priority=</option></term>
  72
  73         <listitem><para>Specify the default priority level for the
  74         logged messages. Pass one of
  75         <literal>emerg</literal>,
  76         <literal>alert</literal>,
  77         <literal>crit</literal>,
  78         <literal>err</literal>,
  79         <literal>warning</literal>,
  80         <literal>notice</literal>,
  81         <literal>info</literal>,
  82         <literal>debug</literal>, or a
  83         value between 0 and 7 (corresponding to the same named
  84         levels). These priority values are the same as defined by
  85         <citerefentry project='man-pages'><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
  86         Defaults to <literal>info</literal>. Note that this simply
  87         controls the default, individual lines may be logged with
  88         different levels if they are prefixed accordingly. For details,
  89         see <option>--level-prefix=</option> below.</para></listitem>
  90       </varlistentry>
  91
  92       <varlistentry>
  93         <term><option>--stderr-priority=</option></term>
  94
  95         <listitem><para>Specifies the default priority level for
  96         messages from the process's standard error output (stderr).
  97         Usage of this option is the same as the
  98         <option>--priority=</option> option, above, and both can be
  99         used at once. When both are used, <option>--priority=</option>
 100         will specify the default priority for standard output (stdout).
 101         </para>
 102
 103         <para>If <option>--stderr-priority=</option> is not specified,
 104         messages from stderr will still be logged, with the same
 105         default priority level as stdout.</para>
 106
 107         <para>Also, note that when stdout and stderr use the same
 108         default priority, the messages will be strictly ordered,
 109         because one channel is used for both. When the default priority
 110         differs, two channels are used, and so stdout messages will not
 111         be strictly ordered with respect to stderr messages - though
 112         they will tend to be approximately ordered.</para></listitem>
 113       </varlistentry>
 114
 115       <varlistentry>
 116         <term><option>--level-prefix=</option></term>
 117
 118         <listitem><para>Controls whether lines read are parsed for syslog priority level prefixes. If enabled
 119         (the default), a line prefixed with a priority prefix such as <literal>&lt;5&gt;</literal> is logged
 120         at priority 5 (<literal>notice</literal>), and similarly for the other priority levels. Takes a
 121         boolean argument.</para></listitem>
 122       </varlistentry>
 123
 124     </variablelist>
 125
 126   </refsect1>
 127
 128   <refsect1>
 129     <title>Exit status</title>
 130
 131     <para>On success, 0 is returned, a non-zero failure code
 132     otherwise.</para>
 133   </refsect1>
 134
 135   <refsect1>
 136     <title>Examples</title>
 137
 138     <example>
 139       <title>Invoke a program</title>
 140
 141       <para>This calls <filename index="false">/bin/ls</filename>
 142       with standard output and error connected to the journal:</para>
 143
 144       <programlisting># systemd-cat ls</programlisting>
 145     </example>
 146
 147     <example>
 148       <title>Usage in a shell pipeline</title>
 149
 150       <para>This builds a shell pipeline also invoking
 151       <filename>/bin/ls</filename> and writes the output it generates
 152       to the journal:</para>
 153
 154       <programlisting># ls | systemd-cat</programlisting>
 155     </example>
 156
 157     <para>Even though the two examples have very similar effects, the first is preferable, since only one
 158     process is running at a time and both stdout and stderr are captured, while in the second example, only
 159     stdout is captured.</para>
 160   </refsect1>
 161
 162   <refsect1>
 163     <title>See Also</title>
 164     <para>
 165       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 166       <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
 167       <citerefentry project='man-pages'><refentrytitle>logger</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 168     </para>
 169   </refsect1>
 170
 171 </refentry>