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 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.
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.
-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.
--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 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 for 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 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.
--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.
--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.
-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 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 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 [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. Also see the Seal= option in journald.conf(5)
for details.
--force
When --setup-keys is passed and Forward Secure Sealing has already
been set up, 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.
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
Show all kernel logs from previous boot:
journalctl -k -b -1
SEE ALSOsystemd(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 207JOURNALCTL(1)