JOURNALCTL(1)                    journalctl                    JOURNALCTL(1)

NAME         top

       journalctl - Query the systemd journal

SYNOPSIS         top

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

DESCRIPTION         top

       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; other lines are displayed

OPTIONS         top

       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) 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.

           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.

               as for short-iso but includes full microsecond precision.

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

               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). To import the binary
               stream back into native journald format use

               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

           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 Documentation[4].

           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

       -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

       --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 four different formats which can be copied into source code
           or similar.

           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

           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.

EXIT STATUS         top

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

ENVIRONMENT         top

           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).

EXAMPLES         top

       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

SEE ALSO         top

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

NOTES         top

        1. Journal Export Format

        2. Journal JSON Format

        3. Server-Sent Events

        4. Message Catalog Developer Documentation

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
       project.  Information about the project can be found at 
       ⟨⟩.  If you have a bug
       report for this manual page, see
       ⟨⟩.  This
       page was obtained from the project's upstream Git repository
       ⟨⟩ on 2018-10-29.  (At that
       time, the date of the most recent commit that was found in the repos‐
       itory was 2018-10-29.)  If you discover any rendering problems in
       this HTML version of the page, or you believe there is a better or
       more up-to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not part
       of the original manual page), send a mail to

systemd 234                                                    JOURNALCTL(1)

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