journalctl - Query the systemd journal


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


   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

   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; other lines are displayed normally.


   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

   -a, --all
       Show all fields in full, even if they include unprintable
       characters or are very long.

   -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)

   -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.

       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:

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

           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

           is very similar, but shows ISO 8601 wallclock timestamps.

           is very similar, but shows timestamps with full microsecond

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

           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.

           shows the full-structured entry items with all fields.

           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).

           formats entries as JSON data structures, one per line (see
           Journal JSON Format[2] for more information).

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

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

           generates a very terse output, only showing the actual message
           of each journal entry with no metadata, not even a timestamp.

       Express time in Coordinated Universal Time (UTC).

       Don't show the hostname field of log messages originating from the
       local host. This switch only has an effect on the short family of
       output modes (see above).

   -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

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

   -q, --quiet
       Suppresses all info messages (i.e. "-- Logs begin 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], --boot=[ID][offset]
       Show messages from a specific boot. This will add a match for

       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.

       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

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

       This parameter can be specified multiple times.

       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.

       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.

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

       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.

       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.

       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).

       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

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

       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 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.

   --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 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.

       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.

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

       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.

       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.

       Specifies the FSS verification key to use for the --verify

       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.

       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,
       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.

       Asks the journal daemon to rotate journal files. This call does not
       return until the rotation operation is complete.

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

       Print a short version string and exit.

       Do not pipe output into a pager.


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


       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

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

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


   Without arguments, all collected logs are shown unfiltered:


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

       journalctl _SYSTEMD_UNIT=avahi-daemon.service

   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

   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


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


    1. Journal Export Format

    2. Journal JSON Format

    3. Server-Sent Events

    4. Message Catalog Developer Documentation


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