| JOURNALCTL(1) | journalctl | JOURNALCTL(1) |
.SH "NAME" journalctl - Print log entries from the systemd
journal
.SH "SYNOPSIS"
.HP 264u
journalctl
[OPTIONS...]
[MATCHES...]
.SH "DESCRIPTION"
.PP journalctl is used to print the log entries stored in the journal
by systemd-journald.service(8) and
systemd-journal-remote.service(8).
.PP If called without parameters, it will show the contents of the journal
accessible to the calling user, starting with the oldest entry
collected.
.PP 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
appear 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).
.PP It is also possible to filter the entries by specifying an absolute file
path as an argument. The file path may be a file or a symbolic link and the
file must exist at the time of the query. If a file path refers to an
executable binary, an _EXE= match for the canonicalized binary path is added
to the query. If a file path refers to an executable script, a _COMM= match
for the script name is added to the query. If a file path refers to a device
node, _KERNEL_DEVICE= matches for the kernel name of the device and for each
of its ancestor devices is added to the query. Symbolic links are
dereferenced, kernel names are synthesized, and parent devices are
identified from the environment at the time of the query. In general, a
device node is the best proxy for an actual device, as log entries do not
usually contain fields that identify an actual device. For the resulting log
entries to be correct for the actual device, the relevant parts of the
environment at the time the entry was logged, in particular the actual
device corresponding to the device node, must have been the same as those at
the time of the query. Because device nodes generally change their
corresponding devices across reboots, specifying a device node path causes
the resulting entries to be restricted to those from the current boot.
.PP Additional constraints may be added using options --boot,
--unit=, etc., to further limit what entries will be shown (logical
AND).
.PP 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 --header
option can be used to identify which files are being shown.
.PP The set of journal files which will be used can be modified using the
--user, --system, --directory=, and --file=
options, see below.
.PP 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 groups systemd-journal, adm, and wheel 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.
.PP 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.
.PP When outputting to a tty, lines are colored according to priority: lines
of level ERROR and higher are colored red; lines of level WARNING are
colored yellow; lines of level NOTICE are highlighted; lines of level INFO
are displayed normally; lines of level DEBUG are colored grey.
.PP To write entries to the journal, a few methods may be used. In
general, output from systemd units is automatically connected to the
journal, see systemd-journald.service(8). In addition,
systemd-cat(1) may be used to send messages to the journal
directly.
.SH "SOURCE OPTIONS"
.PP The following options control where to read journal records from:
.PP --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.
The --user option affects how --unit= arguments are treated.
See --unit=.
Note that --user only works if persistent logging is enabled, via the
Storage= setting in journald.conf(5).
Added in version 205.
.RE
.PP -M, --machine=
Show messages from a running, local container. Specify a container name to
connect to.
Added in version 209.
.RE
.PP -m, --merge
Show entries interleaved from all available journals, including remote
ones.
Added in version 190.
.RE
.PP -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.
Added in version 187.
.RE
.PP -i GLOB, --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.
Added in version 205.
.RE
.PP --root=ROOT
Takes a directory path as an argument. If specified, journalctl will
operate on journal directories and catalog file hierarchy underneath the
specified directory instead of the root directory (e.g.
--update-catalog will create
ROOT/var/lib/systemd/catalog/database, and journal files under
ROOT/run/journal/ or ROOT/var/log/journal/ will be
displayed).
Added in version 201.
.RE
.PP --image=IMAGE
Takes a path to a disk image file or block device node. If specified,
journalctl will operate on the file system in the indicated disk
image. This option is similar to --root=, but operates on file
systems stored in disk images or block devices, thus providing an easy way
to extract log data from disk images. The disk image should either contain
just a file system or a set of file systems within a GPT partition table,
following the UAPI.2 Discoverable Partitions Specification[1]. For
further information on supported disk images, see systemd-nspawn(1)'s
switch of the same name.
Added in version 247.
.RE
.PP --image-policy=policy
Takes an image policy string as argument, as per
systemd.image-policy(7). The policy is enforced when operating on the
disk image specified via --image=, see above. If not specified,
defaults to the * policy, i.e. all recognized file systems in the image are
used.
.RE
.PP --namespace=NAMESPACE
Takes a journal namespace identifier string as argument. If not specified,
the data collected by the default namespace is shown. If specified, shows
the log data of the specified namespace instead. If the namespace is
specified as * data from all namespaces is shown, interleaved. If the
namespace identifier is prefixed with + data from the specified namespace
and the default namespace is shown, interleaved, but no other. For details
about journal namespaces see systemd-journald.service(8).
Added in version 245.
.RE
.SH "FILTERING OPTIONS"
.PP The following options control how to filter journal records:
.PP -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. For complete time and date
specification, see systemd.time(7). Note that
--output=short-full prints timestamps that follow precisely this
format.
Added in version 195.
.RE
.PP -c, --cursor=
Start showing entries from the location in the journal specified by the
passed cursor.
Added in version 193.
.RE
.PP --after-cursor=
Start showing entries from the location in the journal after the
location specified by the passed cursor. The cursor is shown when the
--show-cursor option is used.
Added in version 206.
.RE
.PP --cursor-file=FILE
If FILE exists and contains a cursor, start showing entries
after this location. Otherwise, show entries according to the other
given options. At the end, write the cursor of the last entry to
FILE. Use this option to continually read the journal by sequentially
calling journalctl.
Added in version 242.
.RE
.PP -b [[ID][±offset]|all],
--boot[=[ID][±offset]|all]
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 an 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 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.
The special argument all can be used to negate the effect of an
earlier use of -b.
Added in version 186.
.RE
.PP -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. A match is also added for
_SYSTEMD_SLICE=UNIT, such that if the provided UNIT is a
systemd.slice(5) unit, all logs of children of the slice will be
shown.
With --user, all --unit= arguments will be converted to match
user messages as if specified with --user-unit=.
This parameter can be specified multiple times.
Added in version 195.
.RE
.PP --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. A match is also added for
_SYSTEMD_USER_SLICE=UNIT, such that if the provided UNIT is a
systemd.slice(5) unit, all logs of children of the unit will be
shown.
This parameter can be specified multiple times.
Added in version 198.
.RE
.PP -I,
--invocation=ID[±offset]|offset
Show messages from a specific invocation of unit. This will add a match for
_SYSTEMD_INVOCATION_ID=, OBJECT_SYSTEMD_INVOCATION_ID=, INVOCATION_ID=,
USER_INVOCATION_ID=.
A positive offset will look up the invocations of a systemd unit from
the beginning of the journal, and zero or a negative offset will look up
invocations starting from the end of the journal. Thus, 1 means the
first invocation found in the journal in chronological order, 2 the
second and so on; while 0 is the latest invocation, -1 the
invocation before the latest, and so on.
If the 32-character ID is specified, it may optionally be followed by
±offset which identifies the invocation relative to the one
given by invocation ID. Negative values mean earlier invocations and
positive values mean later invocations. If ±offset is not
specified, a value of zero is assumed, and the logs for the invocation given
by ID will be shown.
-I is equivalent to --invocation=0, and logs for the latest
invocation will be shown.
When an offset is specified, a unit name must be specified with
-u/--unit= or --user-unit= option.
When specified with -b/--boot=, then invocations are searched within
the specified boot.
Added in version 257.
.RE
.PP -t, --identifier=SYSLOG_IDENTIFIER
Show messages for the specified syslog identifier
SYSLOG_IDENTIFIER.
This parameter can be specified multiple times.
Added in version 217.
.RE
.PP -T,
--exclude-identifier=SYSLOG_IDENTIFIER
Exclude messages for the specified syslog identifier
SYSLOG_IDENTIFIER.
This parameter can be specified multiple times.
Added in version 256.
.RE
.PP -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.
Added in version 188.
.RE
.PP --facility=
Filter output by syslog facility. Takes a comma-separated list of numbers or
facility names. The names are the usual syslog facilities as documented in
syslog(3). --facility=help may be used to display a list of
known facility names and exit.
Added in version 245.
.RE
.PP -g, --grep=
Filter output to entries where the MESSAGE= field matches the
specified regular expression. PERL-compatible regular expressions are used,
see pcre2pattern(3) for a detailed description of the syntax.
If the pattern is all lowercase, matching is case insensitive. Otherwise,
matching is case sensitive. This can be overridden with the
--case-sensitive option, see below.
When used with --lines= (not prefixed with +), --reverse is
implied.
Added in version 237.
.RE
.PP --case-sensitive[=BOOLEAN]
Make pattern matching case sensitive or case insensitive.
Added in version 237.
.RE
.PP -k, --dmesg
Show only kernel messages. This adds the match _TRANSPORT=kernel. This
implies --boot=0 unless explicitly specified otherwise.
Added in version 205.
.RE
.SH "OUTPUT OPTIONS"
.PP The following options control how journal records are printed:
.PP -o, --output=
Controls the formatting of the journal entries that are shown. Takes one of
the following options:
.PP 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.
Added in version 206.
.RE
.PP short-full
is very similar, but shows timestamps in the format the --since= and
--until= options accept. Unlike the timestamp information shown in
short output mode this mode includes weekday, year and timezone
information in the output, and is locale-independent.
Added in version 232.
.RE
.PP short-iso
is very similar, but shows timestamps in the RFC 3339[2] profile of
ISO 8601.
Added in version 206.
.RE
.PP short-iso-precise
as for short-iso but includes full microsecond precision.
Added in version 234.
.RE
.PP short-precise
is very similar, but shows classic syslog timestamps with full microsecond
precision.
Added in version 207.
.RE
.PP short-monotonic
is very similar, but shows monotonic timestamps instead of wallclock
timestamps.
Added in version 206.
.RE
.PP short-delta
as for short-monotonic but includes the time difference to the
previous entry. Maybe unreliable time differences are marked by a *.
Added in version 252.
.RE
.PP short-unix
is very similar, but shows seconds passed since January 1st 1970 UTC instead
of wallclock timestamps ("UNIX time"). The time is shown with
microsecond accuracy.
Added in version 230.
.RE
.PP verbose
shows the full-structured entry items with all fields.
Added in version 206.
.RE
.PP export
serializes the journal into a binary (but mostly text-based) stream suitable
for backups and network transfer (see Journal Export Format[3] for
more information). To import the binary stream back into native journald
format use systemd-journal-remote(8).
Added in version 206.
.RE
.PP json
formats entries as JSON objects, separated by newline characters (see
Journal JSON Format[4] for more information). Field values are
generally encoded as JSON strings, with three exceptions:
.sp Note that this encoding is reversible (with the exception of the size
limit).
Added in version 206.
.RE
.PP json-pretty
formats entries as JSON data structures, but formats them in multiple lines
in order to make them more readable by humans.
Added in version 206.
.RE
.PP json-sse
formats entries as JSON data structures, but wraps them in a format suitable
for Server-Sent Events[5].
Added in version 206.
.RE
.PP json-seq
formats entries as JSON data structures, but prefixes them with an ASCII
Record Separator character (0x1E) and suffixes them with an ASCII Line Feed
character (0x0A), in accordance with JavaScript Object Notation (JSON)
Text Sequences[6] (application/json-seq).
Added in version 240.
.RE
.PP cat
generates a very terse output, only showing the actual message of each
journal entry with no metadata, not even a timestamp. If combined with the
--output-fields= option will output the listed fields for each log
record, instead of the message.
Added in version 206.
.RE
.PP with-unit
similar to short-full, but prefixes the unit and user unit names
instead of the traditional syslog identifier. Useful when using templated
instances, as it will include the arguments in the unit names.
Added in version 239.
.RE
.RE
.PP --truncate-newline
Truncate each log message at the first newline character on output, so that
only the first line of each message is displayed.
Added in version 254.
.RE
.PP --output-fields=
A comma separated list of the fields which should be included in the output.
This has an effect only for the output modes which would normally show all
fields (verbose, export, json, json-pretty,
json-sse and json-seq), as well as on cat. For the
former, the __CURSOR, __REALTIME_TIMESTAMP, __MONOTONIC_TIMESTAMP, and
_BOOT_ID fields are always printed.
Added in version 236.
.RE
.PP -n, --lines=
Show the most recent journal events and limit the number of events shown. The
argument is a positive integer or all to disable the limit. Additionally, if
the number is prefixed with +, the oldest journal events are used instead.
The default value is 10 if no argument is given.
If --follow is used, this option is implied. When not prefixed with +
and used with --grep=, --reverse is implied.
.RE
.PP -r, --reverse
Reverse output so that the newest entries are displayed first.
Added in version 198.
.RE
.PP --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.
Added in version 209.
.RE
.PP --utc
Express time in Coordinated Universal Time (UTC).
Added in version 217.
.RE
.PP -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, see Journal Message
Catalogs[7].
Note: when attaching journalctl output to bug reports, please do
not use -x.
Added in version 196.
.RE
.PP -W, --no-hostname
Do not show the hostname field of log messages. This switch has an effect
only on the short family of output modes (see above).
Note: this option does not remove occurrences of the hostname from log
entries themselves, so it does not prevent the hostname from being visible
in the logs.
Added in version 230.
.RE
.PP --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.
Added in version 196.
.RE
.PP -a, --all
Show all fields in full, even if they include unprintable characters or are
very long. By default, fields with unprintable characters are abbreviated as
"blob data". (Note that the pager may escape unprintable
characters again.)
.RE
.PP -f, --follow
Show only the most recent journal entries, and continuously print new entries
as they are appended to the journal, until Ctrl-C is hit (or the tool is
otherwise terminated).
journalctl will send an sd_notify(3) READY=1 message once it
initialized and successfully established its watch on the journal.
.RE
.PP --no-tail
Show all stored output lines, even in follow mode. Undoes the effect of
--lines=.
.RE
.PP -q, --quiet
Suppresses all informational messages (i.e. "-- Journal begins at
...", "-- Reboot --"), any warning messages regarding
inaccessible system journals when run as a normal user.
.RE
.PP --synchronize-on-exit=
Takes a boolean argument. If true and operating in --follow mode, a
journal synchronization request (equivalent to journalctl --sync) is
issued when SIGTERM/SIGINT is received, and log output
continues until this request completes. This is useful for synchronizing
journal log output to the runtime of services or external events, ensuring
that any log data enqueued to the logging subsystem by the time
SIGTERM/SIGINT is issued is guaranteed to be processed and
displayed by the time log output ends. Defaults to false.
Added in version 258.
.RE
.SH "PAGER CONTROL OPTIONS"
.PP The following options control page support:
.PP --no-pager
Do not pipe output into a pager.
.RE
.PP -e, --pager-end
Immediately jump to the end of the journal inside the implied pager tool.
This implies --lines=1000 and --boot=0 unless explicitly
specified otherwise, to guarantee that the pager will not buffer logs of
unbounded size. Note that this option is only supported for the
less(1) pager.
Added in version 198.
.RE
.SH "FORWARD SECURE SEALING (FSS) OPTIONS"
.PP The following options may be used together with the --setup-keys
command described below:
.PP --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.
Note, --output=json-sse and --output=json-seq are silently
migrated to --output=json.
Added in version 189.
.RE
.PP --verify-key=
Specifies the FSS verification key to use for the --verify
operation.
Added in version 189.
.RE
.PP --force
When --setup-keys is passed and Forward Secure Sealing (FSS) has
already been configured, recreate FSS keys.
Added in version 206.
.RE
.SH "COMMANDS"
.PP The following commands are understood. If none is specified the default
is to display journal records:
.PP -N, --fields
Print all field names currently used in all entries of the journal.
Added in version 229.
.RE
.PP -F, --field=
Print all possible data values the specified field can take in all entries of
the journal.
Added in version 195.
.RE
.PP --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. When specified with -n/--lines=[+]N
option, only the first (when the number prefixed with +) or the last
(without prefix) N entries will be shown. When specified with
-r/--reverse, the list will be shown in the reverse order.
Added in version 209.
.RE
.PP --list-invocations
List invocation IDs of a unit. Requires a unit name with -u/--unit= or
--user-unit=. Show a tabular list of invocation numbers (relative to
the current or latest invocation), their IDs, and the timestamps of the
first and last message pertaining to the invocation. When -b/-boot is
specified, invocations in the boot will be shown. When specified with
-n/--lines=[+]N option, only the first (when the
number prefixed with +) or the last (without prefix) N entries will
be shown. When specified with -r/--reverse, the list will be shown in
the reverse order.
Added in version 257.
.RE
.PP --disk-usage
Shows the current disk usage of all journal files. This shows the sum of the
disk usage of all archived and active journal files.
Added in version 190.
.RE
.PP --vacuum-size=, --vacuum-time=, --vacuum-files=
--vacuum-size= removes the oldest archived journal files until the
disk space they use falls below the specified size. Accepts the usual K, M,
G and T suffixes (to the base of 1024).
--vacuum-time= removes archived journal files older than the specified
timespan. Accepts the usual s (default), m, h, days, weeks, months, and
years suffixes, see systemd.time(7) for details.
--vacuum-files= leaves only the specified number of separate journal
files.
Note that running --vacuum-size= has only an indirect effect on the
output shown by --disk-usage, as the latter includes active journal
files, while the vacuuming operation only operates on archived journal
files. Similarly, --vacuum-files= might not actually reduce the
number of journal files to below the specified number, as it will not remove
active journal files.
--vacuum-size=, --vacuum-time= and --vacuum-files= may
be combined in a single invocation to enforce any combination of a size, a
time and a number of files limit on the archived journal files. Specifying
any of these three parameters as zero is equivalent to not enforcing the
specific limit, and is thus redundant.
These three switches may also be combined with --rotate into one
command. If so, all active files are rotated first, and the requested
vacuuming operation is executed right after. The rotation has the effect
that all currently active files are archived (and potentially new, empty
journal files opened as replacement), and hence the vacuuming operation has
the greatest effect as it can take all log data written so far into
account.
Added in version 218.
.RE
.PP --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.
Added in version 189.
.RE
.PP --sync
Asks the journal daemon to write all yet unwritten journal data to the
backing file system and synchronize all journals. This call does not return
until the synchronization operation is complete. This command guarantees
that any log messages written before its invocation are safely stored on
disk at the time it returns.
Added in version 228.
.RE
.PP --relinquish-var
Asks the journal daemon for the reverse operation to --flush: if
requested the daemon will write further log data to /run/log/journal/ and
stops writing to /var/log/journal/. A subsequent call to --flush
causes the log output to switch back to /var/log/journal/, see above.
Added in version 243.
.RE
.PP --smart-relinquish-var
Similar to --relinquish-var, but executes no operation if the root
file system and /var/log/journal/ reside on the same mount point. This
operation is used during system shutdown in order to make the journal daemon
stop writing data to /var/log/journal/ in case that directory is located on
a mount point that needs to be unmounted.
Added in version 243.
.RE
.PP --flush
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. Note that this call is idempotent:
the data is only flushed from /run/log/journal/ into /var/log/journal/ once
during system runtime (but see --relinquish-var below), and this
command exits cleanly without executing any operation if this has already
happened. This command effectively guarantees that all data is flushed to
/var/log/journal/ at the time it returns.
Added in version 217.
.RE
.PP --rotate
Asks the journal daemon to rotate journal files. This call does not return
until the rotation operation is complete. Journal file rotation has the
effect that all currently active journal files are marked as archived and
renamed, so that they are never written to in future. New (empty) journal
files are then created in their place. This operation may be combined with
--vacuum-size=, --vacuum-time= and --vacuum-file= into
a single command, see above.
Added in version 227.
.RE
.PP --header
Instead of showing journal contents, show internal header information of the
journal fields accessed.
This option is particularly useful when trying to identify out-of-order
journal entries, as happens for example when the machine is booted with the
wrong system time.
Added in version 187.
.RE
.PP --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.
Added in version 196.
.RE
.PP --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.
Added in version 199.
.RE
.PP --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.
Added in version 196.
.RE
.PP --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.
Added in version 189.
.RE
.PP -h, --help
Print a short help text and exit.
.RE
.PP --version
Print a short version string and exit.
.RE
.SH "EXIT STATUS"
.PP On success, 0 is returned; otherwise, a non-zero failure code is
returned.
.SH "ENVIRONMENT"
.PP $SYSTEMD_LOG_LEVEL
The maximum log level of emitted messages (messages with a higher log level,
i.e. less important ones, will be suppressed). Takes a comma-separated list
of values. A value may be either one of (in order of decreasing importance)
emerg, alert, crit, err, warning,
notice, info, debug, or an integer in the range 0...7.
See syslog(3) for more information. Each value may optionally be
prefixed with one of console, syslog, kmsg or
journal followed by a colon to set the maximum log level for that
specific log target (e.g. SYSTEMD_LOG_LEVEL=debug,console:info
specifies to log at debug level except when logging to the console which
should be at info level). Note that the global maximum log level takes
priority over any per target maximum log levels.
.RE
.PP $SYSTEMD_LOG_COLOR
A boolean. If true, messages written to the tty will be colored according to
priority.
This setting is only useful when messages are written directly to the
terminal, because journalctl(1) and other tools that display logs
will color messages based on the log level on their own.
.RE
.PP $SYSTEMD_LOG_TIME
A boolean. If true, console log messages will be prefixed with a
timestamp.
This setting is only useful when messages are written directly to the
terminal or a file, because journalctl(1) and other tools that
display logs will attach timestamps based on the entry metadata on their
own.
.RE
.PP $SYSTEMD_LOG_LOCATION
A boolean. If true, messages will be prefixed with a filename and line number
in the source code where the message originates.
Note that the log location is often attached as metadata to journal entries
anyway. Including it directly in the message text can nevertheless be
convenient when debugging programs.
.RE
.PP $SYSTEMD_LOG_TID
A boolean. If true, messages will be prefixed with the current numerical
thread ID (TID).
Note that the this information is attached as metadata to journal entries
anyway. Including it directly in the message text can nevertheless be
convenient when debugging programs.
.RE
.PP $SYSTEMD_LOG_TARGET
The destination for log messages. One of console (log to the attached
tty), console-prefixed (log to the attached tty but with prefixes
encoding the log level and "facility", see syslog(3),
kmsg (log to the kernel circular log buffer), journal (log to
the journal), journal-or-kmsg (log to the journal if available, and
to kmsg otherwise), auto (determine the appropriate log target
automatically, the default), null (disable log output).
.RE
.PP $SYSTEMD_LOG_RATELIMIT_KMSG
Whether to ratelimit kmsg or not. Takes a boolean. Defaults to true. If
disabled, systemd will not ratelimit messages written to kmsg.
.RE
.PP $SYSTEMD_PAGER, $PAGER
Pager to use when --no-pager is not given. $SYSTEMD_PAGER is
used if set; otherwise $PAGER is used. If neither
$SYSTEMD_PAGER nor $PAGER are set, a set of well-known pager
implementations is tried in turn, including less(1) and
more(1), until one is found. If no pager implementation is
discovered, no pager is invoked. Setting those environment variables to an
empty string or the value cat is equivalent to passing
--no-pager.
Note: if $SYSTEMD_PAGERSECURE is not set, $SYSTEMD_PAGER and
$PAGER can only be used to disable the pager (with cat or ), and are
otherwise ignored.
.RE
.PP $SYSTEMD_LESS
Override the options passed to less (by default FRSXMK).
Users might want to change two options in particular:
.PP K
This option instructs the pager to exit immediately when Ctrl+C is pressed.
To allow less to handle Ctrl+C itself to switch back to the pager
command prompt, unset this option.
If the value of $SYSTEMD_LESS does not include K, and the pager that
is invoked is less, Ctrl+C will be ignored by the executable, and
needs to be handled by the pager.
.RE
.PP X
This option instructs the pager to not send termcap initialization and
deinitialization strings to the terminal. It is set by default to allow
command output to remain visible in the terminal even after the pager exits.
Nevertheless, this prevents some pager functionality from working, in
particular paged output cannot be scrolled with the mouse.
.RE
.sp
Note that setting the regular $LESS environment variable has no effect
for less invocations by systemd tools.
See less(1) for more discussion.
.RE
.PP $SYSTEMD_LESSCHARSET
Override the charset passed to less (by default utf-8, if the invoking
terminal is determined to be UTF-8 compatible).
Note that setting the regular $LESSCHARSET environment variable has no
effect for less invocations by systemd tools.
.RE
.PP $SYSTEMD_PAGERSECURE
Common pager commands like less(1), in addition to "paging",
i.e. scrolling through the output, support opening of or writing to other
files and running arbitrary shell commands. When commands are invoked with
elevated privileges, for example under sudo(8) or pkexec(1),
the pager becomes a security boundary. Care must be taken that only programs
with strictly limited functionality are used as pagers, and unintended
interactive features like opening or creation of new files or starting of
subprocesses are not allowed. "Secure mode" for the pager may be
enabled as described below, if the pager supports that (most pagers
are not written in a way that takes this into consideration). It is
recommended to either explicitly enable "secure mode" or to
completely disable the pager using --no-pager or PAGER=cat
when allowing untrusted users to execute commands with elevated
privileges.
This option takes a boolean argument. When set to true, the "secure
mode" of the pager is enabled. In "secure mode",
LESSSECURE=1 will be set when invoking the pager, which instructs the
pager to disable commands that open or create new files or start new
subprocesses. Currently only less(1) is known to understand this
variable and implement "secure mode".
When set to false, no limitation is placed on the pager. Setting
SYSTEMD_PAGERSECURE=0 or not removing it from the inherited
environment may allow the user to invoke arbitrary commands.
When $SYSTEMD_PAGERSECURE is not set, systemd tools attempt to
automatically figure out if "secure mode" should be enabled and
whether the pager supports it. "Secure mode" is enabled if the
effective UID is not the same as the owner of the login session, see
geteuid(2) and sd_pid_get_owner_uid(3), or when running under
sudo(8) or similar tools ($SUDO_UID is set [8]). In those
cases, SYSTEMD_PAGERSECURE=1 will be set and pagers which are not
known to implement "secure mode" will not be used at all. Note
that this autodetection only covers the most common mechanisms to elevate
privileges and is intended as convenience. It is recommended to explicitly
set $SYSTEMD_PAGERSECURE or disable the pager.
Note that if the $SYSTEMD_PAGER or $PAGER variables are to be
honoured, other than to disable the pager, $SYSTEMD_PAGERSECURE must
be set too.
.RE
.PP $SYSTEMD_COLORS
Takes a boolean argument, or a special value. By default (unset),
systemd and related utilities will use colors in their output if
possible. If $COLORTERM is set to truecolor or 24bit, 24-bit colors
will be enabled, 256 colors otherwise, unless $NO_COLOR or
$TERM indicates colors are disabled.
.PP true
Same as unset, except that $NO_COLOR is ignored.
.RE
.PP false
The output will be monochrome.
.RE
.PP 16, 256, 24bit
Always use the base 16 ANSI colors, 256 colors, or 24 bit color,
respectively.
.RE
.PP auto-16, auto-256, auto-24bit
Use the given quantity of colours, subject to $TERM, and what the
console is connected to.
.RE
.sp
.RE
.PP $SYSTEMD_URLIFY
The value must be a boolean. Controls whether clickable links should be
generated in the output for terminal emulators supporting this. This can be
specified to override the decision that systemd makes based on
$TERM and other conditions.
.RE
.SH "EXAMPLES"
.PP Without arguments, all collected logs are shown unfiltered:
journalctl
.PP With one match specified, all entries with a field matching the
expression are shown:
journalctl _SYSTEMD_UNIT=avahi-daemon.service journalctl _SYSTEMD_CGROUP=/user.slice/user-42.slice/session-c1.scope
.PP 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
.PP 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
.PP 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
.PP To show all fields emitted by a unit and about the unit,
option -u/--unit= should be used. journalctl -u
name expands to a complex filter similar to
_SYSTEMD_UNIT=name.service
+ UNIT=name.service _PID=1
+ OBJECT_SYSTEMD_UNIT=name.service _UID=0
+ COREDUMP_UNIT=name.service _UID=0 MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1
(see systemd.journal-fields(7) for an explanation of those patterns).
.PP Show all logs generated by the D-Bus executable:
journalctl /usr/bin/dbus-daemon
.PP Show all kernel logs from previous boot:
journalctl -k -b -1
.PP Show a live log display from a system service apache.service:
journalctl -f -u apache
.SH "SEE ALSO"
.PP systemd(1), systemd-cat(1),
systemd-journald.service(8), systemctl(1),
coredumpctl(1), systemd.journal-fields(7),
journald.conf(5), systemd.time(7),
systemd-journal-remote.service(8),
systemd-journal-upload.service(8)
NOTES
- 1.
- UAPI.2 Discoverable Partitions Specification
- 2.
- RFC 3339
- 3.
- Journal Export Format
- 4.
- Journal JSON Format
- 5.
- Server-Sent Events
- 6.
- JavaScript Object Notation (JSON) Text Sequences
- 7.
- Journal Message Catalogs
- 8.
-
It is recommended for other tools to set and check $SUDO_UID as appropriate, treating it is a common interface.
| systemd 262.2 |