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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 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).

       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 "_EXE=" match for the canonicalized binary path. Similarly, if a
       path refers to a device node then match is added for the kernel name of the device ("_KERNEL_DEVICE="). Also,
       matches for the kernel names of all the parent devices are added automatically. Device node paths are not
       stable across reboots, therefore match for the current boot id ("_BOOT_ID=") is always added as well. Note
       that only the log entries for the existing device nodes maybe queried by providing path to the device node.

       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 the "systemd-journal", "adm", and "wheel" groups 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.

OPTIONS
       The following options are understood:

       --no-full, --full, -l
       -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-iso
               is very similar, but shows ISO 8601 wallclock timestamps.

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

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

           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).

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

           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].

           cat
               generates a very terse output, only showing the actual message of each journal entry with no metadata,

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

       -q, --quiet
           Suppresses 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 "_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 a 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 a 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.

       --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|PATTERN
           Show messages for the specified syslog identifier SYSLOG_IDENTIFIER, or for any of the messages with a
           "SYSLOG_IDENTIFIER" matched by PATTERN.

           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.

       -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

               -- 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.

       -F, --field=
           Print all possible data values the specified field can take 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 catalog file hierarchy
           underneath the specified directory instead of the root directory (e.g.  --update-catalog will create
           ROOT/var/lib/systemd/catalog/database).

       --new-id128
           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.

       --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=
           Removes archived journal files until the disk space they use falls below the specified size (specified

       --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.

       --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.

       -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. Setting this to an empty string or the value
           "cat" is equivalent to passing --no-pager.


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

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

        2. Journal JSON Format
           http://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. Message Catalog Developer Documentation
           http://www.freedesktop.org/wiki/Software/systemd/catalog



systemd 219                                                                                             JOURNALCTL(1)