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 -->
6 <refentry id=
"systemd-cat"
7 xmlns:
xi=
"http://www.w3.org/2001/XInclude">
10 <title>systemd-cat
</title>
11 <productname>systemd
</productname>
15 <refentrytitle>systemd-cat
</refentrytitle>
16 <manvolnum>1</manvolnum>
20 <refname>systemd-cat
</refname>
21 <refpurpose>Connect a pipeline or program's output with the journal
</refpurpose>
26 <command>systemd-cat
<arg choice=
"opt" rep=
"repeat">OPTIONS
</arg> <arg>COMMAND
</arg> <arg choice=
"opt" rep=
"repeat">ARGUMENTS
</arg></command>
29 <command>systemd-cat
<arg choice=
"opt" rep=
"repeat">OPTIONS
</arg></command>
34 <title>Description
</title>
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>
41 <para>If no parameter is passed,
<command>systemd-cat
</command>
42 will write everything it reads from standard input (stdin) to the
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
52 <title>Options
</title>
54 <para>The following options are understood:
</para>
57 <xi:include href=
"standard-options.xml" xpointer=
"help" />
58 <xi:include href=
"standard-options.xml" xpointer=
"version" />
61 <term><option>-t
</option></term>
62 <term><option>--identifier=
</option></term>
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>
70 <term><option>-p
</option></term>
71 <term><option>--priority=
</option></term>
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>
93 <term><option>--stderr-priority=
</option></term>
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).
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>
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>
116 <term><option>--level-prefix=
</option></term>
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><5></literal> is logged
120 at priority
5 (
<literal>notice
</literal>), and similarly for the other priority levels. Takes a
121 boolean argument.
</para></listitem>
129 <title>Exit status
</title>
131 <para>On success,
0 is returned, a non-zero failure code
136 <title>Examples
</title>
139 <title>Invoke a program
</title>
141 <para>This calls
<filename index=
"false">/bin/ls
</filename>
142 with standard output and error connected to the journal:
</para>
144 <programlisting># systemd-cat ls
</programlisting>
148 <title>Usage in a shell pipeline
</title>
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>
154 <programlisting># ls | systemd-cat
</programlisting>
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>
163 <title>See Also
</title>
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>