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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"

"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">

<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 groups

<literal>systemd-journal</literal>, <literal>adm</literal>, and

<literal>wheel</literal> 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 all info messages

(i.e. "-- Logs begin at ...", "-- Reboot --"),

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></option></term>

<listitem><para>Show messages for the specified syslog

identifier

<replaceable>SYSLOG_IDENTIFIER</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>-S</option></term>

<term><option>--since=</option></term>

<term><option>-U</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>

<term><option>--vacuum-files=</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),

or no more than the specified number of separate journal files

remain. 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 the vacuuming operation only operates

on archived journal files. Similar,

<option>--vacuum-files=</option> might not actually reduce the

number of journal files to below the specified number, as it

will not remove active journal

files. <option>--vacuum-size=</option>,

<option>--vacuum-time=</option> and

<option>--vacuum-files=</option> may be combined in a single

invocation to enforce any combination of a size, a time and a

number of files limit on the archived journal

files. Specifying any of these three parameters as zero is

equivalent to not enforcing the specific limit, and is thus

redundant.</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>

<varlistentry>

<term><option>--rotate</option></term>

<listitem><para>Asks the Journal daemon to rotate journal files.

</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 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>