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<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
This file is part of systemd.
Copyright 2012 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
-->
<refentry id="journalctl">
<refentryinfo>
<title>journalctl</title>
<productname>systemd</productname>
<authorgroup>
<author>
<contrib>Developer</contrib>
<firstname>Lennart</firstname>
<surname>Poettering</surname>
<email>lennart@poettering.net</email>
</author>
</authorgroup>
</refentryinfo>
<refmeta>
<refentrytitle>journalctl</refentrytitle>
<manvolnum>1</manvolnum>
</refmeta>
<refnamediv>
<refname>journalctl</refname>
<refpurpose>Query the systemd journal</refpurpose>
</refnamediv>
<refsynopsisdiv>
<cmdsynopsis>
<command>journalctl <arg choice="opt" rep="repeat">OPTIONS</arg> <arg choice="opt" rep="repeat">MATCHES</arg></command>
</cmdsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><command>journalctl</command> may be used to
query the contents of the
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>
journal as written by
<citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
<para>If called without parameter will show the full
contents of the journal, starting with the oldest
entry collected.</para>
<para>If one or more match arguments are passed the
output is filtered accordingly. A match is in the
format <literal>FIELD=VALUE</literal>,
e.g. <literal>_SYSTEMD_UNIT=httpd.service</literal>,
referring to the components of a structured journal
entry. See
<citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
for a list of well-known fields. If multiple matches
are specified matching different fields the log
entries are filtered by both, i.e. the resulting output
will show only entries matching all the specified
matches of this kind. If two matches apply to the same
field, then they are automatically matched as
alternatives, i.e. the resulting output will show
entries matching any of the specified matches for the
same field. Finally, if the character
"<literal>+</literal>" appears as separate word on the
command line all matches before and after are combined
in a disjunction (i.e. logical OR).</para>
<para>Output is interleaved from all accessible
journal files, whether they are rotated or currently
being written, and regardless whether they belong to the
system itself or are accessible user journals.</para>
<para>All users are granted access to their private
per-user journals. However, by default only root and
users who are members of the <literal>adm</literal>
group get access to the system journal and the
journals of other users.</para>
</refsect1>
<refsect1>
<title>Options</title>
<para>The following options are understood:</para>
<variablelist>
<varlistentry>
<term><option>--help</option></term>
<term><option>-h</option></term>
<listitem><para>Prints a short help
text and exits.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--version</option></term>
<listitem><para>Prints a short version
string and exits.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--no-pager</option></term>
<listitem><para>Do not pipe output into a
pager.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--all</option></term>
<term><option>-a</option></term>
<listitem><para>Show all fields in
full, even if they include unprintable
characters or are very
long.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--follow</option></term>
<term><option>-f</option></term>
<listitem><para>Show only most recent
journal entries, and continuously print
new entries as they are appended to
the journal.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--lines=</option></term>
<term><option>-n</option></term>
<listitem><para>Controls the number of
journal lines to show, counting from
the most recent ones. Takes a positive
integer argument. In follow mode
defaults to 10, otherwise is unset
thus not limiting how many lines are
shown.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--no-tail</option></term>
<listitem><para>Show all stored output
lines, even in follow mode. Undoes the
effect of
<option>--lines=</option>.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--output=</option></term>
<term><option>-o</option></term>
<listitem><para>Controls the
formatting of the journal entries that are
shown. Takes one of
<literal>short</literal>,
<literal>short-monotonic</literal>,
<literal>verbose</literal>,
<literal>export</literal>,
<literal>json</literal>,
<literal>cat</literal>. <literal>short</literal>
is the default and generates an output
that is mostly identical to the
formatting of classic syslog log
files, showing one line per journal
entry. <literal>short-monotonic</literal>
is very similar but shows monotonic
timestamps instead of wallclock
timestamps. <literal>verbose</literal>
shows the full structured entry items
with all
fields. <literal>export</literal>
serializes the journal into a binary
(but mostly text-based) stream
suitable for backups and network
transfer. <literal>json</literal>
formats entries as JSON data
structures. <literal>cat</literal>
generates a very terse output only
showing the actual message of each
journal entry with no meta data, not
even a timestamp.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--quiet</option></term>
<term><option>-q</option></term>
<listitem><para>Suppresses any warning
message regarding inaccessible system
journals when run as normal
user.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--local</option></term>
<term><option>-l</option></term>
<listitem><para>Show only locally
generated messages.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--this-boot</option></term>
<term><option>-b</option></term>
<listitem><para>Show data only from
current boot.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--directory=</option></term>
<term><option>-D</option></term>
<listitem><para>Takes an absolute
directory path as argument. If
specified will operate on the
specified journal directory instead of
the default runtime and system journal
paths.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--new-id128</option></term>
<listitem><para>Instead of showing
journal contents generate a new 128
bit ID suitable for identifying
messages. This is intended for usage
by developers who need a new
identifier for a new message they
introduce and want to make
recognizable. Will print the new ID in
three different formats which can be
copied into source code or
similar.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--header</option></term>
<listitem><para>Instead of showing
journal contents show internal header
information of the journal fiels
accessed.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Exit status</title>
<para>On success 0 is returned, a non-zero failure
code otherwise.</para>
</refsect1>
<refsect1>
<title>Environment</title>
<variablelist>
<varlistentry>
<term><varname>$SYSTEMD_PAGER</varname></term>
<listitem><para>Pager to use when
<option>--no-pager</option> is not given;
overrides <varname>$PAGER</varname>. Setting
this to an empty string or the value
<literal>cat</literal> is equivalent to passing
<option>--no-pager</option>.</para></listitem>
</varlistentry>
</variablelist>
</refsect1>
<refsect1>
<title>Examples</title>
<para>Without arguments all collected logs are shown
unfiltered:</para>
<programlisting>journalctl</programlisting>
<para>With one match specified all entries with a field matching the expression are shown:</para>
<programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service</programlisting>
<para>If two different fields are matched only entries matching both expressions at the same time are shown:</para>
<programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097</programlisting>
<para>If two matches refer to the same field all entries matching either expression are shown:</para>
<programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service</programlisting>
<para>If the separator "<literal>+</literal>" is used
two expression may be combined in a logical OR. The
following will show all messages from the Avahi
service process with the PID 28097 plus all messages
from the D-Bus service (from any of its
processes):</para>
<programlisting>journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service</programlisting>
</refsect1>
<refsect1>
<title>See Also</title>
<para>
<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
<citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
<citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>
|
