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 parameter 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, if the character "+"
       appears as separate word on the command line all matches before and after are 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. Similar, if a path refers to a device node, this is equivalent
       to a _KERNEL_DEVICE= match for the device.

       Output is interleaved from all accessible journal files, whether they are rotated or
       currently being written, and regardless whether they belong to the system itself or are
       accessible user journals.

       All users are granted access to their private per-user journals. However, by default only
       root and users who are members of the adm group get access to the system journal and the
       journals of other users.

OPTIONS

       The following options are understood:

       -h, --help
           Prints a short help text and exits.

       --version
           Prints a short version string and exits.

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

       --full
           Show all (printable) fields in full.

       -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 won't buffer logs of unbounded size. This may be
           overridden with an explicit -n with some other numeric value on the command line. 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, a positive integer, is optional, and
           defaults to 10.

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

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

       -o, --output=
           Controls the formatting of the journal entries that are shown. Takes one of short,
           short-monotonic, verbose, export, json, json-pretty, json-sse, cat.  short is the
           default and generates an output that is mostly identical to the formatting of classic
           syslog log files, showing one line per journal entry.  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 also formats entries as JSON data structures, but formats them in multiple
           lines in order to make them more readable for humans.  json-sse also 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 meta data, not even a timestamp.

       -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].

       -q, --quiet
           Suppresses any warning message regarding inaccessible system journals when run as
           normal user.

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

       -b, --this-boot
           Show data only from current boot. This will add a match for _BOOT_ID= for the current
           boot ID of the kernel.

       -u, --unit=
           Show messages for the specified systemd unit. This will add a match for messages from
           the unit (_SYSTEMD_UNIT=) and additional matches for messages from systemd and
           messages about coredumps for the specified unit.

           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.

           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.

       --since=, --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.

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

       --root=ROOT
           Takes a directory path as 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. 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.

       --list-catalog [ID128...]
           List the contents of the message catalog, as table of message IDs plus their short
           description strings.

           If any ID128s are specified, only those entries are shown.

       --dump-catalog [ID128...]
           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 ID128s 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.

       --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.

EXIT STATUS

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

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.

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

       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 logs of the kernel device node /dev/sda:

           journalctl /dev/sda

SEE ALSO

       systemd(1), systemd-journald.service(8), systemctl(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