journalctl man page on Archlinux

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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, if
       the character "+" appears as a 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.
       Similarly, 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 of 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
       "systemd-journal" group get access to the system journal and the
       journals of other users.

       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 outputing 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
	   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.

       -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 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 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, 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].

	   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".

       -u, --unit=UNIT|PATTERN
	   Show messages for the specified systemd unit 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.

       --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.

       --after-cursor=
	   Start showing entries from the location in the journal after the
	   location specified by the this 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.

       --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.

       --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.

       --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.

       -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.

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

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

       Show all kernel logs from previous boot:

	   journalctl -k -b -1

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

systemd 212							 JOURNALCTL(1)
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