Unix/Linux Go Back    

CentOS 7.0 - man page for journalctl (centos section 1)

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)

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

       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 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 --no-pager and section Environment 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, and other lines
       are displayed normally.

       The following options are understood:

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

	   Prints a short version string and exits.

	   Do not pipe output into a pager.

       -l, --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 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.

	   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 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 precision.

	       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 for 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 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].

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

       -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 [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 the chronological order, 2 the second and so on; while -0 is the last boot,
	   -1 the boot before that, 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.

       -k, --dmesg
	   Show only kernel messages. This implies -b and adds the match "_TRANSPORT=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.

	   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.

	   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 this the cursor is private and subject ot 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

       --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.

       -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

	   Takes a file glob as 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 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.

       --list-catalog [128-bit-ID...]
	   List the contents of the message catalog, as 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 has already been set up,
	   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 operation.

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

	   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.

       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 logs of the kernel device node /dev/sda:

	   journalctl /dev/sda

       Show all kernel logs from previous boot:

	   journalctl -k -b -1

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

	1. Journal Export Format

	2. Journal JSON Format

	3. Server-Sent Events

	4. Message Catalog Developer Documentation

systemd 208									    JOURNALCTL(1)
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums

All times are GMT -4. The time now is 05:45 AM.