eudev/man/journalctl.xml

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<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">MATCH</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 a match argument is passed the output is
                filtered accordingly. A match is in the format
                <literal>FIELD=VALUE</literal>,
                e.g. <literal>_SYSTEMD_UNIT=httpd.service</literal>. See
                <citerefentry><refentrytitle>systemd.journal-fields</refentrytitle><manvolnum>7</manvolnum></citerefentry>
                for a list of well-known fields.</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 continously 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 structered entry items
                                with all
                                fiels. <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 inaccessable 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>

                </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>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>