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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" 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>As shortcuts for a few types of field/value

matches file paths may be specified. If a file path

refers to an executable file, this is equivalent to an

<literal>_EXE=</literal> match for the canonicalized

binary path. Similar, if a path refers to a device

node, this is equivalent to a

<literal>_KERNEL_DEVICE=</literal> match for the

device.</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 (see <ulink

url="http://www.freedesktop.org/wiki/Software/systemd/export">Journal

Export Format</ulink> for more

information). <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>

<varlistentry>

<term><option>-p</option></term>

<term><option>--priority=</option></term>

<listitem><para>Filter output by

message priorities or priority

ranges. Takes either a single numeric

or textual log level (i.e. between

0/<literal>emerg</literal> and

7/<literal>debug</literal>), or a

range of numeric/text log levels in

the form FROM..TO. The log levels are

the usual syslog log levels as

documented in

<citerefentry><refentrytitle>syslog</refentrytitle><manvolnum>3</manvolnum></citerefentry>,

i.e. <literal>emerg</literal> (0),

<literal>alert</literal> (1),

<literal>crit</literal> (2),

<literal>err</literal> (3),

<literal>warning</literal> (4),

<literal>notice</literal> (5),

<literal>info</literal> (6),

<literal>debug</literal> (7). If a

single log level is specified all

messages with this log levels or a

lower (hence more important) log level

are shown. If a range is specified all

messages within the range are shown,

including both the start and the end

value of the range.</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>

<para>Show all logs generated by the D-Bus executable:</para>

<programlisting>journalctl /usr/bin/dbus-daemon</programlisting>

<para>Show all logs of the kernel device node <filename>/dev/sda</filename>:</para>

<programlisting>journalctl /dev/sda</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>