journalctl(1) - Query the systemd journal

  • JOURNALCTL(1)			  journalctl			 JOURNALCTL(1)
           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 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.
           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 ISO 8601 wallclock timestamps.
    	       is very similar, but shows timestamps with full microsecond
    	       is very similar, but shows monotonic timestamps instead of
    	       wallclock timestamps.
    	       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).
           -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 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 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.
    	   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|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 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 this 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.
           -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.
    	   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 catalog file hierarchy underneath the specified
    	   directory instead of the root directory (e.g.  --update-catalog
    	   will create ROOT/var/lib/systemd/catalog/database).
    	   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=
    	   Removes archived journal files until the disk space they use falls
    	   below the specified size (specified with the usual "K", "M", "G",
    	   "T" suffixes), or all journal files contain no data older than the
    	   specified timespan (specified with the usual "s", "min", "h",
    	   "days", "months", "weeks", "years" suffixes). Note that running
    	   --vacuum-size= has only indirect effect on the output shown by
    	   --disk-usage as the latter includes active journal files, while the
    	   former only operates on archived journal files.  --vacuum-size= and
    	   --vacuum-time= may be combined in a single invocation to enforce
    	   both a size and time limit on the archived 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 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 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.
    	   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.
    	   Setting this to an empty string or the value "cat" is equivalent to
    	   passing --no-pager.
    	   Override the default options passed to less ("FRSXMK").
           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)
    	1. Journal Export Format
    	2. Journal JSON Format
    	3. Server-Sent Events
    	4. Message Catalog Developer Documentation
    systemd 219							 JOURNALCTL(1)

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