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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">
<!--
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Copyright 2012 Lennart Poettering
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<refentry id="journalctl"
xmlns:xi="http://www.w3.org/2001/XInclude">
<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</command>
<arg choice="opt" rep="repeat">OPTIONS</arg>
<arg choice="opt" rep="repeat">MATCHES</arg>
</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 parameters, it 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, the character <literal>+</literal> may appears
as a separate word between other terms on the command line. This
causes all matches before and after to be 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. Similarly, if a path refers
to a device node, this is equivalent to a
<literal>_KERNEL_DEVICE=</literal> match for the device.</para>
<para>Additional constraints may be added using options
<option>--boot</option>, <option>--unit=</option>, etc, to
further limit what entries will be shown (logical AND).</para>
<para>Output is interleaved from all accessible journal files,
whether they are rotated or currently being written, and
regardless of whether they belong to the system itself or are
accessible user journals.</para>
<para>The set of journal files which will be used can be
modified using the <option>--user</option>,
<option>--system</option>, <option>--directory</option>, and
<option>--file</option> options, see below.</para>
<para>All users are granted access to their private per-user
journals. However, by default, only root and users who are
members of a few special groups are granted access to the system
journal and the journals of other users. Members of the the
<literal>systemd-journal</literal>, <literal>adm</literal>, and
<literal>wheel</literal> groups can read all journal files. Note
that the two latter groups traditionally have additional
privileges specified by the distribution. Members of the
<literal>wheel</literal> group can often perform administrative
tasks.</para>
<para>The output is paged through <command>less</command> by
default, and long lines are "truncated" to screen width. The
hidden part can be viewed by using the left-arrow and
right-arrow keys. Paging can be disabled; see the
<option>--no-pager</option> option and the "Environment" section
below.</para>
<para>When outputting to a tty, lines are colored according to
priority: lines of level ERROR and higher are colored red; lines
of level NOTICE and higher are highlighted; other lines are
displayed normally.</para>
</refsect1>
<refsect1>
<title>Options</title>
<para>The following options are understood:</para>
<variablelist>
<varlistentry>
<term><option>--no-full</option></term>
<term><option>--full</option></term>
<term><option>-l</option></term>
<listitem><para>Ellipsize fields when they do not fit in
available columns. The default is to show full fields,
allowing them to wrap or be truncated by the pager, if one
is used.</para>
<para>The old options
<option>-l</option>/<option>--full</option> are not useful
anymore, except to undo <option>--no-full</option>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-a</option></term>
<term><option>--all</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>-f</option></term>
<term><option>--follow</option></term>
<listitem><para>Show only the most recent journal entries,
and continuously print new entries as they are appended to
the journal.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-e</option></term>
<term><option>--pager-end</option></term>
<listitem><para>Immediately jump to the end of the journal
inside the implied pager tool. This implies
<option>-n1000</option> to guarantee that the pager will not
buffer logs of unbounded size. This may be overridden with
an explicit <option>-n</option> with some other numeric
value while <option>-nall</option> will disable this cap.
Note that this option is only supported for the
<citerefentry project='man-pages'><refentrytitle>less</refentrytitle><manvolnum>1</manvolnum></citerefentry>
pager.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-n</option></term>
<term><option>--lines=</option></term>
<listitem><para>Show the most recent journal events and
limit the number of events shown. If
<option>--follow</option> is used, this option is
implied. The argument is a positive integer or
<literal>all</literal> to disable line limiting. The default
value is 10 if no argument is given.</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>-r</option></term>
<term><option>--reverse</option></term>
<listitem><para>Reverse output so that the newest entries
are displayed first.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-o</option></term>
<term><option>--output=</option></term>
<listitem><para>Controls the formatting of the journal
entries that are shown. Takes one of the following
options:</para>
<variablelist>
<varlistentry>
<term>
<option>short</option>
</term>
<listitem>
<para>is the default and generates an output that is
mostly identical to the formatting of classic syslog
files, showing one line per journal entry.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>short-iso</option>
</term>
<listitem>
<para>is very similar, but shows ISO 8601 wallclock
timestamps.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>short-precise</option>
</term>
<listitem>
<para>is very similar, but shows timestamps with full
microsecond precision.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>short-monotonic</option>
</term>
<listitem>
<para>is very similar, but shows monotonic timestamps
instead of wallclock timestamps.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>verbose</option>
</term>
<listitem>
<para>shows the full-structured entry items with all
fields.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>export</option>
</term>
<listitem>
<para>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).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>json</option>
</term>
<listitem>
<para>formats entries as JSON data structures, one per
line (see
<ulink url="http://www.freedesktop.org/wiki/Software/systemd/json">Journal JSON Format</ulink>
for more information).</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>json-pretty</option>
</term>
<listitem>
<para>formats entries as JSON data structures, but
formats them in multiple lines in order to make them
more readable by humans.</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>json-sse</option>
</term>
<listitem>
<para>formats entries as JSON data structures, but wraps
them in a format suitable for
<ulink url="https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events">Server-Sent Events</ulink>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<option>cat</option>
</term>
<listitem>
<para>generates a very terse output, only showing the
actual message of each journal entry with no metadata,
not even a timestamp.</para>
</listitem>
</varlistentry>
</variablelist>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--utc</option></term>
<listitem><para>Express time in Coordinated Universal Time
(UTC).</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-x</option></term>
<term><option>--catalog</option></term>
<listitem><para>Augment log lines with explanation texts from
the message catalog. This will add explanatory help texts to
log messages in the output where this is available. These
short help texts will explain the context of an error or log
event, possible solutions, as well as pointers to support
forums, developer documentation, and any other relevant
manuals. Note that help texts are not available for all
messages, but only for selected ones. For more information on
the message catalog, please refer to the
<ulink url="http://www.freedesktop.org/wiki/Software/systemd/catalog">Message Catalog Developer Documentation</ulink>.</para>
<para>Note: when attaching <command>journalctl</command>
output to bug reports, please do <emphasis>not</emphasis> use
<option>-x</option>.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-q</option></term>
<term><option>--quiet</option></term>
<listitem><para>Suppresses any warning messages regarding
inaccessible system journals when run as a normal
user.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-m</option></term>
<term><option>--merge</option></term>
<listitem><para>Show entries interleaved from all available
journals, including remote ones.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-b <optional><replaceable>ID</replaceable></optional><optional><replaceable>±offset</replaceable></optional></option></term>
<term><option>--boot=<optional><replaceable>ID</replaceable></optional><optional><replaceable>±offset</replaceable></optional></option></term>
<listitem><para>Show messages from a specific boot. This will
add a match for <literal>_BOOT_ID=</literal>.</para>
<para>The argument may be empty, in which case logs for the
current boot will be shown.</para>
<para>If the boot ID is omitted, a positive
<replaceable>offset</replaceable> will look up the boots
starting from the beginning of the journal, and a
equal-or-less-than zero <replaceable>offset</replaceable> will
look up boots starting from the end of the journal. Thus,
<constant>1</constant> means the first boot found in the
journal in chronological order, <constant>2</constant> the
second and so on; while <constant>-0</constant> is the last
boot, <constant>-1</constant> the boot before last, and so
on. An empty <replaceable>offset</replaceable> is equivalent
to specifying <constant>-0</constant>, except when the current
boot is not the last boot (e.g. because
<option>--directory</option> was specified to look at logs
from a different machine).</para>
<para>If the 32-character <replaceable>ID</replaceable> is
specified, it may optionally be followed by
<replaceable>offset</replaceable> which identifies the boot
relative to the one given by boot
<replaceable>ID</replaceable>. Negative values mean earlier
boots and a positive values mean later boots. If
<replaceable>offset</replaceable> is not specified, a value of
zero is assumed, and the logs for the boot given by
<replaceable>ID</replaceable> are shown.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--list-boots</option></term>
<listitem><para>Show a tabular list of boot numbers (relative to
the current boot), their IDs, and the timestamps of the first
and last message pertaining to the boot.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-k</option></term>
<term><option>--dmesg</option></term>
<listitem><para>Show only kernel messages. This implies
<option>-b</option> and adds the match
<literal>_TRANSPORT=kernel</literal>.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-t</option></term>
<term><option>--identifier=<replaceable>SYSLOG_IDENTIFIER</replaceable>|<replaceable>PATTERN</replaceable></option></term>
<listitem><para>Show messages for the specified syslog
identifier <replaceable>SYSLOG_IDENTIFIER</replaceable>, or
for any of the messages with a
<literal>SYSLOG_IDENTIFIER</literal> matched by
<replaceable>PATTERN</replaceable>.</para>
<para>This parameter can be specified multiple
times.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-u</option></term>
<term><option>--unit=<replaceable>UNIT</replaceable>|<replaceable>PATTERN</replaceable></option></term>
<listitem><para>Show messages for the specified systemd unit
<replaceable>UNIT</replaceable> (such as a service unit), or
for any of the units matched by
<replaceable>PATTERN</replaceable>. If a pattern is
specified, a list of unit names found in the journal is
compared with the specified pattern and all that match are
used. For each unit name, a match is added for messages from
the unit
(<literal>_SYSTEMD_UNIT=<replaceable>UNIT</replaceable></literal>),
along with additional matches for messages from systemd and
messages about coredumps for the specified unit.</para>
<para>This parameter can be specified multiple times.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--user-unit=</option></term>
<listitem><para>Show messages for the specified user session
unit. This will add a match for messages from the unit
(<literal>_SYSTEMD_USER_UNIT=</literal> and
<literal>_UID=</literal>) and additional matches for messages
from session systemd and messages about coredumps for the
specified unit.</para>
<para>This parameter can be specified multiple times.</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 project='man-pages'><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 level 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. This will add
<literal>PRIORITY=</literal> matches for the specified
priorities.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-c</option></term>
<term><option>--cursor=</option></term>
<listitem><para>Start showing entries from the location in the
journal specified by the passed cursor.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--after-cursor=</option></term>
<listitem><para>Start showing entries from the location in the
journal <emphasis>after</emphasis> the location specified by
the this cursor. The cursor is shown when the
<option>--show-cursor</option> option is used.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--show-cursor</option></term>
<listitem><para>The cursor is shown after the last entry after
two dashes:</para>
<programlisting>-- cursor: s=0639...</programlisting>
<para>The format of the cursor is private
and subject to change.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--since=</option></term>
<term><option>--until=</option></term>
<listitem><para>Start showing entries on or newer than the
specified date, or on or older than the specified date,
respectively. Date specifications should be of the format
<literal>2012-10-30 18:17:16</literal>. If the time part is
omitted, <literal>00:00:00</literal> is assumed. If only the
seconds component is omitted, <literal>:00</literal> is
assumed. If the date component is omitted, the current day is
assumed. Alternatively the strings
<literal>yesterday</literal>, <literal>today</literal>,
<literal>tomorrow</literal> are understood, which refer to
00:00:00 of the day before the current day, the current day,
or the day after the current day,
respectively. <literal>now</literal> refers to the current
time. Finally, relative times may be specified, prefixed with
<literal>-</literal> or <literal>+</literal>, referring to
times before or after the current time, respectively.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-F</option></term>
<term><option>--field=</option></term>
<listitem><para>Print all possible data values the specified
field can take in all entries of the journal.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--system</option></term>
<term><option>--user</option></term>
<listitem><para>Show messages from system services and the
kernel (with <option>--system</option>). Show messages from
service of current user (with <option>--user</option>). If
neither is specified, show all messages that the user can see.
</para></listitem>
</varlistentry>
<varlistentry>
<term><option>-M</option></term>
<term><option>--machine=</option></term>
<listitem><para>Show messages from a running, local
container. Specify a container name to connect to.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>-D <replaceable>DIR</replaceable></option></term>
<term><option>--directory=<replaceable>DIR</replaceable></option></term>
<listitem><para>Takes a directory path as argument. If
specified, journalctl will operate on the specified journal
directory <replaceable>DIR</replaceable> instead of the
default runtime and system journal paths.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--file=<replaceable>GLOB</replaceable></option></term>
<listitem><para>Takes a file glob as an argument. If
specified, journalctl will operate on the specified journal
files matching <replaceable>GLOB</replaceable> instead of the
default runtime and system journal paths. May be specified
multiple times, in which case files will be suitably
interleaved.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--root=<replaceable>ROOT</replaceable></option></term>
<listitem><para>Takes a directory path as an argument. If
specified, journalctl will operate on catalog file hierarchy
underneath the specified directory instead of the root
directory (e.g. <option>--update-catalog</option> will create
<filename><replaceable>ROOT</replaceable>/var/lib/systemd/catalog/database</filename>).
</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. This 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 fields
accessed.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--disk-usage</option></term>
<listitem><para>Shows the current disk usage of all journal
files. This shows the sum of the disk usage of all archived
and active journal files.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--vacuum-size=</option></term>
<term><option>--vacuum-time=</option></term>
<listitem><para>Removes archived journal files until the disk
space they use falls below the specified size (specified with
the usual <literal>K</literal>, <literal>M</literal>,
<literal>G</literal>, <literal>T</literal> suffixes), or all
journal files contain no data older than the specified
timespan (specified with the usual <literal>s</literal>,
<literal>min</literal>, <literal>h</literal>,
<literal>days</literal>, <literal>months</literal>,
<literal>weeks</literal>, <literal>years</literal>
suffixes). Note that running <option>--vacuum-size=</option>
has only indirect effect on the output shown by
<option>--disk-usage</option> as the latter includes active
journal files, while the former only operates on archived
journal files. <option>--vacuum-size=</option> and
<option>--vacuum-time=</option> may be combined in a single
invocation to enforce both a size and time limit on the
archived journal files.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--list-catalog
<optional><replaceable>128-bit-ID...</replaceable></optional>
</option></term>
<listitem><para>List the contents of the message catalog as a
table of message IDs, plus their short description strings.
</para>
<para>If any <replaceable>128-bit-ID</replaceable>s are
specified, only those entries are shown.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--dump-catalog
<optional><replaceable>128-bit-ID...</replaceable></optional>
</option></term>
<listitem><para>Show the contents of the message catalog, with
entries separated by a line consisting of two dashes and the
ID (the format is the same as <filename>.catalog</filename>
files).</para>
<para>If any <replaceable>128-bit-ID</replaceable>s are
specified, only those entries are shown.</para>
</listitem>
</varlistentry>
<varlistentry>
<term><option>--update-catalog</option></term>
<listitem><para>Update the message catalog index. This command
needs to be executed each time new catalog files are
installed, removed, or updated to rebuild the binary catalog
index.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--setup-keys</option></term>
<listitem><para>Instead of showing journal contents, generate
a new key pair for Forward Secure Sealing (FSS). This will
generate a sealing key and a verification key. The sealing key
is stored in the journal data directory and shall remain on
the host. The verification key should be stored
externally. Refer to the <option>Seal=</option> option in
<citerefentry><refentrytitle>journald.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
for information on Forward Secure Sealing and for a link to a
refereed scholarly paper detailing the cryptographic theory it
is based on.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--force</option></term>
<listitem><para>When <option>--setup-keys</option> is passed
and Forward Secure Sealing (FSS) has already been configured,
recreate FSS keys.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--interval=</option></term>
<listitem><para>Specifies the change interval for the sealing
key when generating an FSS key pair with
<option>--setup-keys</option>. Shorter intervals increase CPU
consumption but shorten the time range of undetectable journal
alterations. Defaults to 15min.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--verify</option></term>
<listitem><para>Check the journal file for internal
consistency. If the file has been generated with FSS enabled and
the FSS verification key has been specified with
<option>--verify-key=</option>, authenticity of the journal file
is verified.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--verify-key=</option></term>
<listitem><para>Specifies the FSS verification key to use for
the <option>--verify</option> operation.</para></listitem>
</varlistentry>
<varlistentry>
<term><option>--flush</option></term>
<listitem><para>Asks the Journal daemon to flush any log data
stored in <filename>/run/log/journal</filename> into
<filename>/var/log/journal</filename>, if persistent storage is
enabled. This call does not return until the operation is
complete.</para></listitem>
</varlistentry>
<xi:include href="standard-options.xml" xpointer="help" />
<xi:include href="standard-options.xml" xpointer="version" />
<xi:include href="standard-options.xml" xpointer="no-pager" />
</variablelist>
</refsect1>
<refsect1>
<title>Exit status</title>
<para>On success, 0 is returned; otherwise, a non-zero failure
code is returned.</para>
</refsect1>
<xi:include href="less-variables.xml" />
<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
expressions 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 noindex='true'>/dev/sda</filename>:</para>
<programlisting>journalctl /dev/sda</programlisting>
<para>Show all kernel logs from previous boot:</para>
<programlisting>journalctl -k -b -1</programlisting>
<para>Show a live log display from a system service
<filename>apache.service</filename>:</para>
<programlisting>journalctl -f -u apache</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>coredumpctl</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>
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