journalctl

JOURNALCTL(1)                      journalctl                      JOURNALCTL(1)



NAME
       journalctl - Query the systemd journal

SYNOPSIS
       journalctl [OPTIONS...] [MATCHES...]

DESCRIPTION
       journalctl may be used to query the contents of the systemd(1) journal as
       written by systemd-journald.service(8).

       If called without parameters, it will show the full contents of the
       journal, starting with the oldest entry collected.

       If one or more match arguments are passed, the output is filtered
       accordingly. A match is in the format "FIELD=VALUE", e.g.
       "_SYSTEMD_UNIT=httpd.service", referring to the components of a
       structured journal entry. See systemd.journal-fields(7) 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 "+" may appear 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).

       It is also possible to filter the entries by specifying an absolute file
       path as an argument. The file path may be a file or a symbolic link and
       the file must exist at the time of the query. If a file path refers to an
       executable binary, an "_EXE=" match for the canonicalized binary path is
       added to the query. If a file path refers to an executable script, a
       "_COMM=" match for the script name is added to the query. If a file path
       refers to a device node, "_KERNEL_DEVICE=" matches for the kernel name of
       the device and for each of its ancestor devices is added to the query.
       Symbolic links are dereferenced, kernel names are synthesized, and parent
       devices are identified from the environment at the time of the query. In
       general, a device node is the best proxy for an actual device, as log
       entries do not usually contain fields that identify an actual device. For
       the resulting log entries to be correct for the actual device, the
       relevant parts of the environment at the time the entry was logged, in
       particular the actual device corresponding to the device node, must have
       been the same as those at the time of the query. Because device nodes
       generally change their corresponding devices across reboots, specifying a
       device node path causes the resulting entries to be restricted to those
       from the current boot.

       Additional constraints may be added using options --boot, --unit=, etc.,
       to further limit what entries will be shown (logical AND).

       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.

       The set of journal files which will be used can be modified using the
       --user, --system, --directory, and --file options, see below.

       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 "systemd-journal", "adm", and "wheel" can read all
       journal files. Note that the two latter groups traditionally have
       additional privileges specified by the distribution. Members of the
       "wheel" group can often perform administrative tasks.

       The output is paged through less 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
       --no-pager option and the "Environment" section below.

       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; lines of level DEBUG are colored lighter grey;
       other lines are displayed normally.

OPTIONS
       The following options are understood:

       --no-full, --full, -l
           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.

           The old options -l/--full are not useful anymore, except to undo
           --no-full.

       -a, --all
           Show all fields in full, even if they include unprintable characters
           or are very long. By default, fields with unprintable characters are
           abbreviated as "blob data". (Note that the pager may escape
           unprintable characters again.)

       -f, --follow
           Show only the most recent journal entries, and continuously print new
           entries as they are appended to the journal.

       -e, --pager-end
           Immediately jump to the end of the journal inside the implied pager
           tool. This implies -n1000 to guarantee that the pager will not buffer
           logs of unbounded size. This may be overridden with an explicit -n
           with some other numeric value, while -nall will disable this cap.
           Note that this option is only supported for the less(1) pager.

       -n, --lines=
           Show the most recent journal events and limit the number of events
           shown. If --follow is used, this option is implied. The argument is a
           positive integer or "all" to disable line limiting. The default value
           is 10 if no argument is given.

       --no-tail
           Show all stored output lines, even in follow mode. Undoes the effect
           of --lines=.

       -r, --reverse
           Reverse output so that the newest entries are displayed first.

       -o, --output=
           Controls the formatting of the journal entries that are shown. Takes
           one of the following options:

           short
               is the default and generates an output that is mostly identical
               to the formatting of classic syslog files, showing one line per
               journal entry.

           short-full
               is very similar, but shows timestamps in the format the --since=
               and --until= options accept. Unlike the timestamp information
               shown in short output mode this mode includes weekday, year and
               timezone information in the output, and is locale-independent.

           short-iso
               is very similar, but shows ISO 8601 wallclock timestamps.

           short-iso-precise
               as for short-iso but includes full microsecond precision.

           short-precise
               is very similar, but shows classic syslog timestamps with full
               microsecond precision.

           short-monotonic
               is very similar, but shows monotonic timestamps instead of
               wallclock timestamps.

           short-unix
               is very similar, but shows seconds passed since January 1st 1970
               UTC instead of wallclock timestamps ("UNIX time"). The time is
               shown with microsecond accuracy.

           verbose
               shows the full-structured entry items with all fields.

           export
               serializes the journal into a binary (but mostly text-based)
               stream suitable for backups and network transfer (see Journal
               Export Format[1] for more information). To import the binary
               stream back into native journald format use systemd-journal-
               remote(8).

           json
               formats entries as JSON objects, separated by newline characters
               (see Journal JSON Format[2] for more information). Field values
               are generally encoded as JSON strings, with three exceptions:

                1. Fields larger than 4096 bytes are encoded as null values.
                   (This may be turned off by passing --all, but be aware that
                   this may allocate overly long JSON objects.)

                2. Journal entries permit non-unique fields within the same log
                   entry. JSON does not allow non-unique fields within objects.
                   Due to this, if a non-unique field is encountered a JSON
                   array is used as field value, listing all field values as
                   elements.

                3. Fields containing non-printable or non-UTF8 bytes are encoded
                   as arrays containing the raw bytes individually formatted as
                   unsigned numbers.

               Note that this encoding is reversible (with the exception of the
               size limit).

           json-pretty
               formats entries as JSON data structures, but formats them in
               multiple lines in order to make them more readable by humans.

           json-sse
               formats entries as JSON data structures, but wraps them in a
               format suitable for Server-Sent Events[3].

           json-seq
               formats entries as JSON data structures, but prefixes them with
               an ASCII Record Separator character (0x1E) and suffixes them with
               an ASCII Line Feed character (0x0A), in accordance with
               JavaScript Object Notation (JSON) Text Sequences[4]
               ("application/json-seq").

           cat
               generates a very terse output, only showing the actual message of
               each journal entry with no metadata, not even a timestamp. If
               combined with the --output-fields= option will output the listed
               fields for each log record, instead of the message.

           with-unit
               similar to short-full, but prefixes the unit and user unit names
               instead of the traditional syslog identifier. Useful when using
               templated instances, as it will include the arguments in the unit
               names.

       --output-fields=
           A comma separated list of the fields which should be included in the
           output. This has an effect only for the output modes which would
           normally show all fields (verbose, export, json, json-pretty,
           json-sse and json-seq), as well as on cat. For the former, the
           "__CURSOR", "__REALTIME_TIMESTAMP", "__MONOTONIC_TIMESTAMP", and
           "_BOOT_ID" fields are always printed.

       --utc
           Express time in Coordinated Universal Time (UTC).

       --no-hostname
           Don't show the hostname field of log messages originating from the
           local host. This switch has an effect only on the short family of
           output modes (see above).

           Note: this option does not remove occurrences of the hostname from
           log entries themselves, so it does not prevent the hostname from
           being visible in the logs.

       -x, --catalog
           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 Message Catalog Developer
           Documentation[5].

           Note: when attaching journalctl output to bug reports, please do not
           use -x.

       -q, --quiet
           Suppresses all informational messages (i.e. "-- Journal begins at
           ...", "-- Reboot --"), any warning messages regarding inaccessible
           system journals when run as a normal user.

       -m, --merge
           Show entries interleaved from all available journals, including
           remote ones.

       -b [[ID][┬▒offset]|all], --boot[=[ID][┬▒offset]|all]
           Show messages from a specific boot. This will add a match for
           "_BOOT_ID=".

           The argument may be empty, in which case logs for the current boot
           will be shown.

           If the boot ID is omitted, a positive offset will look up the boots
           starting from the beginning of the journal, and an equal-or-less-than
           zero offset will look up boots starting from the end of the journal.
           Thus, 1 means the first boot found in the journal in chronological
           order, 2 the second and so on; while -0 is the last boot, -1 the boot
           before last, and so on. An empty offset is equivalent to specifying
           -0, except when the current boot is not the last boot (e.g. because
           --directory was specified to look at logs from a different machine).

           If the 32-character ID is specified, it may optionally be followed by
           offset which identifies the boot relative to the one given by boot
           ID. Negative values mean earlier boots and positive values mean later
           boots. If offset is not specified, a value of zero is assumed, and
           the logs for the boot given by ID are shown.

           The special argument all can be used to negate the effect of an
           earlier use of -b.

       --list-boots
           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.

       -k, --dmesg
           Show only kernel messages. This implies -b and adds the match
           "_TRANSPORT=kernel".

       -t, --identifier=SYSLOG_IDENTIFIER
           Show messages for the specified syslog identifier SYSLOG_IDENTIFIER.

           This parameter can be specified multiple times.

       -u, --unit=UNIT|PATTERN
           Show messages for the specified systemd unit UNIT (such as a service
           unit), or for any of the units matched by PATTERN. 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
           ("_SYSTEMD_UNIT=UNIT"), along with additional matches for messages
           from systemd and messages about coredumps for the specified unit. A
           match is also added for "_SYSTEMD_SLICE=UNIT", such that if the
           provided UNIT is a systemd.slice(5) unit, all logs of children of the
           slice will be shown.

           This parameter can be specified multiple times.

       --user-unit=
           Show messages for the specified user session unit. This will add a
           match for messages from the unit ("_SYSTEMD_USER_UNIT=" and "_UID=")
           and additional matches for messages from session systemd and messages
           about coredumps for the specified unit. A match is also added for
           "_SYSTEMD_USER_SLICE=UNIT", such that if the provided UNIT is a
           systemd.slice(5) unit, all logs of children of the unit will be
           shown.

           This parameter can be specified multiple times.

       -p, --priority=
           Filter output by message priorities or priority ranges. Takes either
           a single numeric or textual log level (i.e. between 0/"emerg" and
           7/"debug"), 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 syslog(3), i.e.  "emerg" (0), "alert" (1), "crit" (2),
           "err" (3), "warning" (4), "notice" (5), "info" (6), "debug" (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 "PRIORITY="
           matches for the specified priorities.

       --facility=
           Filter output by syslog facility. Takes a comma-separated list of
           numbers or facility names. The names are the usual syslog facilities
           as documented in syslog(3).  --facility=help may be used to display a
           list of known facility names and exit.

       -g, --grep=
           Filter output to entries where the MESSAGE= field matches the
           specified regular expression. PERL-compatible regular expressions are
           used, see pcre2pattern(3) for a detailed description of the syntax.

           If the pattern is all lowercase, matching is case insensitive.
           Otherwise, matching is case sensitive. This can be overridden with
           the --case-sensitive option, see below.

       --case-sensitive[=BOOLEAN]
           Make pattern matching case sensitive or case insensitive.

       -c, --cursor=
           Start showing entries from the location in the journal specified by
           the passed cursor.

       --cursor-file=FILE
           If FILE exists and contains a cursor, start showing entries after
           this location. Otherwise the show entries according the other given
           options. At the end, write the cursor of the last entry to FILE. Use
           this option to continually read the journal by sequentially calling
           journalctl.

       --after-cursor=
           Start showing entries from the location in the journal after the
           location specified by the passed cursor. The cursor is shown when the
           --show-cursor option is used.

       --show-cursor
           The cursor is shown after the last entry after two dashes:

               -- cursor: s=0639...

           The format of the cursor is private and subject to change.

       -S, --since=, -U, --until=
           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 "2012-10-30 18:17:16". If the time part is
           omitted, "00:00:00" is assumed. If only the seconds component is
           omitted, ":00" is assumed. If the date component is omitted, the
           current day is assumed. Alternatively the strings "yesterday",
           "today", "tomorrow" 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.  "now" refers to the current time.
           Finally, relative times may be specified, prefixed with "-" or "+",
           referring to times before or after the current time, respectively.
           For complete time and date specification, see systemd.time(7). Note
           that --output=short-full prints timestamps that follow precisely this
           format.

       -F, --field=
           Print all possible data values the specified field can take in all
           entries of the journal.

       -N, --fields
           Print all field names currently used in all entries of the journal.

       --system, --user
           Show messages from system services and the kernel (with --system).
           Show messages from service of current user (with --user). If neither
           is specified, show all messages that the user can see.

       -M, --machine=
           Show messages from a running, local container. Specify a container
           name to connect to.

       -D DIR, --directory=DIR
           Takes a directory path as argument. If specified, journalctl will
           operate on the specified journal directory DIR instead of the default
           runtime and system journal paths.

       --file=GLOB
           Takes a file glob as an argument. If specified, journalctl will
           operate on the specified journal files matching GLOB instead of the
           default runtime and system journal paths. May be specified multiple
           times, in which case files will be suitably interleaved.

       --root=ROOT
           Takes a directory path as an argument. If specified, journalctl will
           operate on journal directories and catalog file hierarchy underneath
           the specified directory instead of the root directory (e.g.
           --update-catalog will create ROOT/var/lib/systemd/catalog/database,
           and journal files under ROOT/run/journal/ or ROOT/var/log/journal/
           will be displayed).

       --image=IMAGE
           Takes a path to a disk image file or block device node. If specified,
           journalctl will operate on the file system in the indicated disk
           image. This is similar to --root= but operates on file systems stored
           in disk images or block devices, thus providing an easy way to
           extract log data from disk images. The disk image should either
           contain just a file system or a set of file systems within a GPT
           partition table, following the Discoverable Partitions
           Specification[6]. For further information on supported disk images,
           see systemd-nspawn(1)'s switch of the same name.

       --namespace=NAMESPACE
           Takes a journal namespace identifier string as argument. If not
           specified the data collected by the default namespace is shown. If
           specified shows the log data of the specified namespace instead. If
           the namespace is specified as "*" data from all namespaces is shown,
           interleaved. If the namespace identifier is prefixed with "+" data
           from the specified namespace and the default namespace is shown,
           interleaved, but no other. For details about journal namespaces see
           systemd-journald.service(8).

       --header
           Instead of showing journal contents, show internal header information
           of the journal fields accessed.

       --disk-usage
           Shows the current disk usage of all journal files. This shows the sum
           of the disk usage of all archived and active journal files.

       --vacuum-size=, --vacuum-time=, --vacuum-files=
           Removes the oldest archived journal files until the disk space they
           use falls below the specified size (specified with the usual "K",
           "M", "G" and "T" suffixes), or all archived journal files contain no
           data older than the specified timespan (specified with the usual "s",
           "m", "h", "days", "months", "weeks" and "years" suffixes), or no more
           than the specified number of separate journal files remain. Note that
           running --vacuum-size= has only an indirect effect on the output
           shown by --disk-usage, as the latter includes active journal files,
           while the vacuuming operation only operates on archived journal
           files. Similarly, --vacuum-files= might not actually reduce the
           number of journal files to below the specified number, as it will not
           remove active journal files.

           --vacuum-size=, --vacuum-time= and --vacuum-files= 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.

           These three switches may also be combined with --rotate into one
           command. If so, all active files are rotated first, and the requested
           vacuuming operation is executed right after. The rotation has the
           effect that all currently active files are archived (and potentially
           new, empty journal files opened as replacement), and hence the
           vacuuming operation has the greatest effect as it can take all log
           data written so far into account.

       --list-catalog [128-bit-ID...]
           List the contents of the message catalog as a table of message IDs,
           plus their short description strings.

           If any 128-bit-IDs are specified, only those entries are shown.

       --dump-catalog [128-bit-ID...]
           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
           .catalog files).

           If any 128-bit-IDs are specified, only those entries are shown.

       --update-catalog
           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.

       --setup-keys
           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 Seal= option in journald.conf(5)
           for information on Forward Secure Sealing and for a link to a
           refereed scholarly paper detailing the cryptographic theory it is
           based on.

       --force
           When --setup-keys is passed and Forward Secure Sealing (FSS) has
           already been configured, recreate FSS keys.

       --interval=
           Specifies the change interval for the sealing key when generating an
           FSS key pair with --setup-keys. Shorter intervals increase CPU
           consumption but shorten the time range of undetectable journal
           alterations. Defaults to 15min.

       --verify
           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 --verify-key=, authenticity of the journal file is
           verified.

       --verify-key=
           Specifies the FSS verification key to use for the --verify operation.

       --sync
           Asks the journal daemon to write all yet unwritten journal data to
           the backing file system and synchronize all journals. This call does
           not return until the synchronization operation is complete. This
           command guarantees that any log messages written before its
           invocation are safely stored on disk at the time it returns.

       --flush
           Asks the journal daemon to flush any log data stored in
           /run/log/journal/ into /var/log/journal/, if persistent storage is
           enabled. This call does not return until the operation is complete.
           Note that this call is idempotent: the data is only flushed from
           /run/log/journal/ into /var/log/journal/ once during system runtime
           (but see --relinquish-var below), and this command exits cleanly
           without executing any operation if this has already happened. This
           command effectively guarantees that all data is flushed to
           /var/log/journal/ at the time it returns.

       --relinquish-var
           Asks the journal daemon for the reverse operation to --flush: if
           requested the daemon will write further log data to /run/log/journal/
           and stops writing to /var/log/journal/. A subsequent call to --flush
           causes the log output to switch back to /var/log/journal/, see above.

       --smart-relinquish-var
           Similar to --relinquish-var but executes no operation if the root
           file system and /var/lib/journal/ reside on the same mount point.
           This operation is used during system shutdown in order to make the
           journal daemon stop writing data to /var/log/journal/ in case that
           directory is located on a mount point that needs to be unmounted.

       --rotate
           Asks the journal daemon to rotate journal files. This call does not
           return until the rotation operation is complete. Journal file
           rotation has the effect that all currently active journal files are
           marked as archived and renamed, so that they are never written to in
           future. New (empty) journal files are then created in their place.
           This operation may be combined with --vacuum-size=, --vacuum-time=
           and --vacuum-file= into a single command, see above.

       -h, --help
           Print a short help text and exit.

       --version
           Print a short version string and exit.

       --no-pager
           Do not pipe output into a pager.

EXIT STATUS
       On success, 0 is returned; otherwise, a non-zero failure code is
       returned.

ENVIRONMENT
       $SYSTEMD_PAGER
           Pager to use when --no-pager is not given; overrides $PAGER. If
           neither $SYSTEMD_PAGER nor $PAGER are set, a set of well-known pager
           implementations are tried in turn, including less(1) and more(1),
           until one is found. If no pager implementation is discovered no pager
           is invoked. Setting this environment variable to an empty string or
           the value "cat" is equivalent to passing --no-pager.

       $SYSTEMD_LESS
           Override the options passed to less (by default "FRSXMK").

           Users might want to change two options in particular:

           K
               This option instructs the pager to exit immediately when Ctrl+C
               is pressed. To allow less to handle Ctrl+C itself to switch back
               to the pager command prompt, unset this option.

               If the value of $SYSTEMD_LESS does not include "K", and the pager
               that is invoked is less, Ctrl+C will be ignored by the
               executable, and needs to be handled by the pager.

           X
               This option instructs the pager to not send termcap
               initialization and deinitialization strings to the terminal. It
               is set by default to allow command output to remain visible in
               the terminal even after the pager exits. Nevertheless, this
               prevents some pager functionality from working, in particular
               paged output cannot be scrolled with the mouse.

           See less(1) for more discussion.

       $SYSTEMD_LESSCHARSET
           Override the charset passed to less (by default "utf-8", if the
           invoking terminal is determined to be UTF-8 compatible).

       $SYSTEMD_PAGERSECURE
           Takes a boolean argument. When true, the "secure" mode of the pager
           is enabled; if false, disabled. If $SYSTEMD_PAGERSECURE is not set at
           all, secure mode is enabled if the effective UID is not the same as
           the owner of the login session, see geteuid(2) and
           sd_pid_get_owner_uid(3). In secure mode, LESSSECURE=1 will be set
           when invoking the pager, and the pager shall disable commands that
           open or create new files or start new subprocesses. When
           $SYSTEMD_PAGERSECURE is not set at all, pagers which are not known to
           implement secure mode will not be used. (Currently only less(1)
           implements secure mode.)

           Note: when commands are invoked with elevated privileges, for example
           under sudo(8) or pkexec(1), care must be taken to ensure that
           unintended interactive features are not enabled. "Secure" mode for
           the pager may be enabled automatically as describe above. Setting
           SYSTEMD_PAGERSECURE=0 or not removing it from the inherited
           environment allows the user to invoke arbitrary commands. Note that
           if the $SYSTEMD_PAGER or $PAGER variables are to be honoured,
           $SYSTEMD_PAGERSECURE must be set too. It might be reasonable to
           completely disable the pager using --no-pager instead.

       $SYSTEMD_COLORS
           The value must be a boolean. Controls whether colorized output should
           be generated. This can be specified to override the decision that
           systemd makes based on $TERM and what the console is connected to.

       $SYSTEMD_URLIFY
           The value must be a boolean. Controls whether clickable links should
           be generated in the output for terminal emulators supporting this.
           This can be specified to override the decision that systemd makes
           based on $TERM and other conditions.

EXAMPLES
       Without arguments, all collected logs are shown unfiltered:

           journalctl

       With one match specified, all entries with a field matching the
       expression are shown:

           journalctl _SYSTEMD_UNIT=avahi-daemon.service
           journalctl _SYSTEMD_CGROUP=/user.slice/user-42.slice/session-c1.scope

       If two different fields are matched, only entries matching both
       expressions at the same time are shown:

           journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097

       If two matches refer to the same field, all entries matching either
       expression are shown:

           journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service

       If the separator "+" 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):

           journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service

       To show all fields emitted by a unit and about the unit, option
       -u/--unit= should be used.  journalctl -u name expands to a complex
       filter similar to

           _SYSTEMD_UNIT=name.service
             + UNIT=name.service _PID=1
             + OBJECT_SYSTEMD_UNIT=name.service _UID=0
             + COREDUMP_UNIT=name.service _UID=0 MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1


       (see systemd.journal-fields(7) for an explanation of those patterns).

       Show all logs generated by the D-Bus executable:

           journalctl /usr/bin/dbus-daemon

       Show all kernel logs from previous boot:

           journalctl -k -b -1

       Show a live log display from a system service apache.service:

           journalctl -f -u apache

SEE ALSO
       systemd(1), systemd-journald.service(8), systemctl(1), coredumpctl(1),
       systemd.journal-fields(7), journald.conf(5), systemd.time(7), systemd-
       journal-remote.service(8), systemd-journal-upload.service(8)

NOTES
        1. Journal Export Format
           https://www.freedesktop.org/wiki/Software/systemd/export

        2. Journal JSON Format
           https://www.freedesktop.org/wiki/Software/systemd/json

        3. Server-Sent Events
           https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events

        4. JavaScript Object Notation (JSON) Text Sequences
           https://tools.ietf.org/html/rfc7464

        5. Message Catalog Developer Documentation
           https://www.freedesktop.org/wiki/Software/systemd/catalog

        6. Discoverable Partitions Specification
           https://systemd.io/DISCOVERABLE_PARTITIONS



systemd 247                                                        JOURNALCTL(1)