1JOURNALCTL(1)                     journalctl                     JOURNALCTL(1)
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3
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NAME

6       journalctl - Query the systemd journal
7

SYNOPSIS

9       journalctl [OPTIONS...] [MATCHES...]
10

DESCRIPTION

12       journalctl may be used to query the contents of the systemd(1) journal
13       as written by systemd-journald.service(8).
14
15       If called without parameters, it will show the full contents of the
16       journal, starting with the oldest entry collected.
17
18       If one or more match arguments are passed, the output is filtered
19       accordingly. A match is in the format "FIELD=VALUE", e.g.
20       "_SYSTEMD_UNIT=httpd.service", referring to the components of a
21       structured journal entry. See systemd.journal-fields(7) for a list of
22       well-known fields. If multiple matches are specified matching different
23       fields, the log entries are filtered by both, i.e. the resulting output
24       will show only entries matching all the specified matches of this kind.
25       If two matches apply to the same field, then they are automatically
26       matched as alternatives, i.e. the resulting output will show entries
27       matching any of the specified matches for the same field. Finally, the
28       character "+" may appear as a separate word between other terms on the
29       command line. This causes all matches before and after to be combined
30       in a disjunction (i.e. logical OR).
31
32       It is also possible to filter the entries by specifying an absolute
33       file path as an argument. The file path may be a file or a symbolic
34       link and the file must exist at the time of the query. If a file path
35       refers to an executable binary, an "_EXE=" match for the canonicalized
36       binary path is added to the query. If a file path refers to an
37       executable script, a "_COMM=" match for the script name is added to the
38       query. If a file path refers to a device node, "_KERNEL_DEVICE="
39       matches for the kernel name of the device and for each of its ancestor
40       devices is added to the query. Symbolic links are dereferenced, kernel
41       names are synthesized, and parent devices are identified from the
42       environment at the time of the query. In general, a device node is the
43       best proxy for an actual device, as log entries do not usually contain
44       fields that identify an actual device. For the resulting log entries to
45       be correct for the actual device, the relevant parts of the environment
46       at the time the entry was logged, in particular the actual device
47       corresponding to the device node, must have been the same as those at
48       the time of the query. Because device nodes generally change their
49       corresponding devices across reboots, specifying a device node path
50       causes the resulting entries to be restricted to those from the current
51       boot.
52
53       Additional constraints may be added using options --boot, --unit=,
54       etc., to further limit what entries will be shown (logical AND).
55
56       Output is interleaved from all accessible journal files, whether they
57       are rotated or currently being written, and regardless of whether they
58       belong to the system itself or are accessible user journals.
59
60       The set of journal files which will be used can be modified using the
61       --user, --system, --directory, and --file options, see below.
62
63       All users are granted access to their private per-user journals.
64       However, by default, only root and users who are members of a few
65       special groups are granted access to the system journal and the
66       journals of other users. Members of the groups "systemd-journal",
67       "adm", and "wheel" can read all journal files. Note that the two latter
68       groups traditionally have additional privileges specified by the
69       distribution. Members of the "wheel" group can often perform
70       administrative tasks.
71
72       The output is paged through less by default, and long lines are
73       "truncated" to screen width. The hidden part can be viewed by using the
74       left-arrow and right-arrow keys. Paging can be disabled; see the
75       --no-pager option and the "Environment" section below.
76
77       When outputting to a tty, lines are colored according to priority:
78       lines of level ERROR and higher are colored red; lines of level NOTICE
79       and higher are highlighted; lines of level DEBUG are colored lighter
80       grey; other lines are displayed normally.
81

OPTIONS

83       The following options are understood:
84
85       --no-full, --full, -l
86           Ellipsize fields when they do not fit in available columns. The
87           default is to show full fields, allowing them to wrap or be
88           truncated by the pager, if one is used.
89
90           The old options -l/--full are not useful anymore, except to undo
91           --no-full.
92
93       -a, --all
94           Show all fields in full, even if they include unprintable
95           characters or are very long. By default, fields with unprintable
96           characters are abbreviated as "blob data". (Note that the pager may
97           escape unprintable characters again.)
98
99       -f, --follow
100           Show only the most recent journal entries, and continuously print
101           new entries as they are appended to the journal.
102
103       -e, --pager-end
104           Immediately jump to the end of the journal inside the implied pager
105           tool. This implies -n1000 to guarantee that the pager will not
106           buffer logs of unbounded size. This may be overridden with an
107           explicit -n with some other numeric value, while -nall will disable
108           this cap. Note that this option is only supported for the less(1)
109           pager.
110
111       -n, --lines=
112           Show the most recent journal events and limit the number of events
113           shown. If --follow is used, this option is implied. The argument is
114           a positive integer or "all" to disable line limiting. The default
115           value is 10 if no argument is given.
116
117       --no-tail
118           Show all stored output lines, even in follow mode. Undoes the
119           effect of --lines=.
120
121       -r, --reverse
122           Reverse output so that the newest entries are displayed first.
123
124       -o, --output=
125           Controls the formatting of the journal entries that are shown.
126           Takes one of the following options:
127
128           short
129               is the default and generates an output that is mostly identical
130               to the formatting of classic syslog files, showing one line per
131               journal entry.
132
133           short-full
134               is very similar, but shows timestamps in the format the
135               --since= and --until= options accept. Unlike the timestamp
136               information shown in short output mode this mode includes
137               weekday, year and timezone information in the output, and is
138               locale-independent.
139
140           short-iso
141               is very similar, but shows ISO 8601 wallclock timestamps.
142
143           short-iso-precise
144               as for short-iso but includes full microsecond precision.
145
146           short-precise
147               is very similar, but shows classic syslog timestamps with full
148               microsecond precision.
149
150           short-monotonic
151               is very similar, but shows monotonic timestamps instead of
152               wallclock timestamps.
153
154           short-unix
155               is very similar, but shows seconds passed since January 1st
156               1970 UTC instead of wallclock timestamps ("UNIX time"). The
157               time is shown with microsecond accuracy.
158
159           verbose
160               shows the full-structured entry items with all fields.
161
162           export
163               serializes the journal into a binary (but mostly text-based)
164               stream suitable for backups and network transfer (see Journal
165               Export Format[1] for more information). To import the binary
166               stream back into native journald format use systemd-journal-
167               remote(8).
168
169           json
170               formats entries as JSON objects, separated by newline
171               characters (see Journal JSON Format[2] for more information).
172               Field values are generally encoded as JSON strings, with three
173               exceptions:
174
175                1. Fields larger than 4096 bytes are encoded as null values.
176                   (This may be turned off by passing --all, but be aware that
177                   this may allocate overly long JSON objects.)
178
179                2. Journal entries permit non-unique fields within the same
180                   log entry. JSON does not allow non-unique fields within
181                   objects. Due to this, if a non-unique field is encountered
182                   a JSON array is used as field value, listing all field
183                   values as elements.
184
185                3. Fields containing non-printable or non-UTF8 bytes are
186                   encoded as arrays containing the raw bytes individually
187                   formatted as unsigned numbers.
188
189               Note that this encoding is reversible (with the exception of
190               the size limit).
191
192           json-pretty
193               formats entries as JSON data structures, but formats them in
194               multiple lines in order to make them more readable by humans.
195
196           json-sse
197               formats entries as JSON data structures, but wraps them in a
198               format suitable for Server-Sent Events[3].
199
200           json-seq
201               formats entries as JSON data structures, but prefixes them with
202               an ASCII Record Separator character (0x1E) and suffixes them
203               with an ASCII Line Feed character (0x0A), in accordance with
204               JavaScript Object Notation (JSON) Text Sequences[4]
205               ("application/json-seq").
206
207           cat
208               generates a very terse output, only showing the actual message
209               of each journal entry with no metadata, not even a timestamp.
210               If combined with the --output-fields= option will output the
211               listed fields for each log record, instead of the message.
212
213           with-unit
214               similar to short-full, but prefixes the unit and user unit
215               names instead of the traditional syslog identifier. Useful when
216               using templated instances, as it will include the arguments in
217               the unit names.
218
219       --output-fields=
220           A comma separated list of the fields which should be included in
221           the output. This has an effect only for the output modes which
222           would normally show all fields (verbose, export, json, json-pretty,
223           json-sse and json-seq), as well as on cat. For the former, the
224           "__CURSOR", "__REALTIME_TIMESTAMP", "__MONOTONIC_TIMESTAMP", and
225           "_BOOT_ID" fields are always printed.
226
227       --utc
228           Express time in Coordinated Universal Time (UTC).
229
230       --no-hostname
231           Don't show the hostname field of log messages originating from the
232           local host. This switch has an effect only on the short family of
233           output modes (see above).
234
235           Note: this option does not remove occurrences of the hostname from
236           log entries themselves, so it does not prevent the hostname from
237           being visible in the logs.
238
239       -x, --catalog
240           Augment log lines with explanation texts from the message catalog.
241           This will add explanatory help texts to log messages in the output
242           where this is available. These short help texts will explain the
243           context of an error or log event, possible solutions, as well as
244           pointers to support forums, developer documentation, and any other
245           relevant manuals. Note that help texts are not available for all
246           messages, but only for selected ones. For more information on the
247           message catalog, please refer to the Message Catalog Developer
248           Documentation[5].
249
250           Note: when attaching journalctl output to bug reports, please do
251           not use -x.
252
253       -q, --quiet
254           Suppresses all informational messages (i.e. "-- Journal begins at
255           ...", "-- Reboot --"), any warning messages regarding inaccessible
256           system journals when run as a normal user.
257
258       -m, --merge
259           Show entries interleaved from all available journals, including
260           remote ones.
261
262       -b [[ID][±offset]|all], --boot[=[ID][±offset]|all]
263           Show messages from a specific boot. This will add a match for
264           "_BOOT_ID=".
265
266           The argument may be empty, in which case logs for the current boot
267           will be shown.
268
269           If the boot ID is omitted, a positive offset will look up the boots
270           starting from the beginning of the journal, and an
271           equal-or-less-than zero offset will look up boots starting from the
272           end of the journal. Thus, 1 means the first boot found in the
273           journal in chronological order, 2 the second and so on; while -0 is
274           the last boot, -1 the boot before last, and so on. An empty offset
275           is equivalent to specifying -0, except when the current boot is not
276           the last boot (e.g. because --directory was specified to look at
277           logs from a different machine).
278
279           If the 32-character ID is specified, it may optionally be followed
280           by offset which identifies the boot relative to the one given by
281           boot ID. Negative values mean earlier boots and positive values
282           mean later boots. If offset is not specified, a value of zero is
283           assumed, and the logs for the boot given by ID are shown.
284
285           The special argument all can be used to negate the effect of an
286           earlier use of -b.
287
288       --list-boots
289           Show a tabular list of boot numbers (relative to the current boot),
290           their IDs, and the timestamps of the first and last message
291           pertaining to the boot.
292
293       -k, --dmesg
294           Show only kernel messages. This implies -b and adds the match
295           "_TRANSPORT=kernel".
296
297       -t, --identifier=SYSLOG_IDENTIFIER
298           Show messages for the specified syslog identifier
299           SYSLOG_IDENTIFIER.
300
301           This parameter can be specified multiple times.
302
303       -u, --unit=UNIT|PATTERN
304           Show messages for the specified systemd unit UNIT (such as a
305           service unit), or for any of the units matched by PATTERN. If a
306           pattern is specified, a list of unit names found in the journal is
307           compared with the specified pattern and all that match are used.
308           For each unit name, a match is added for messages from the unit
309           ("_SYSTEMD_UNIT=UNIT"), along with additional matches for messages
310           from systemd and messages about coredumps for the specified unit. A
311           match is also added for "_SYSTEMD_SLICE=UNIT", such that if the
312           provided UNIT is a systemd.slice(5) unit, all logs of children of
313           the slice will be shown.
314
315           This parameter can be specified multiple times.
316
317       --user-unit=
318           Show messages for the specified user session unit. This will add a
319           match for messages from the unit ("_SYSTEMD_USER_UNIT=" and
320           "_UID=") and additional matches for messages from session systemd
321           and messages about coredumps for the specified unit. A match is
322           also added for "_SYSTEMD_USER_SLICE=UNIT", such that if the
323           provided UNIT is a systemd.slice(5) unit, all logs of children of
324           the unit will be shown.
325
326           This parameter can be specified multiple times.
327
328       -p, --priority=
329           Filter output by message priorities or priority ranges. Takes
330           either a single numeric or textual log level (i.e. between
331           0/"emerg" and 7/"debug"), or a range of numeric/text log levels in
332           the form FROM..TO. The log levels are the usual syslog log levels
333           as documented in syslog(3), i.e.  "emerg" (0), "alert" (1),
334           "crit" (2), "err" (3), "warning" (4), "notice" (5), "info" (6),
335           "debug" (7). If a single log level is specified, all messages with
336           this log level or a lower (hence more important) log level are
337           shown. If a range is specified, all messages within the range are
338           shown, including both the start and the end value of the range.
339           This will add "PRIORITY=" matches for the specified priorities.
340
341       --facility=
342           Filter output by syslog facility. Takes a comma-separated list of
343           numbers or facility names. The names are the usual syslog
344           facilities as documented in syslog(3).  --facility=help may be used
345           to display a list of known facility names and exit.
346
347       -g, --grep=
348           Filter output to entries where the MESSAGE= field matches the
349           specified regular expression. PERL-compatible regular expressions
350           are used, see pcre2pattern(3) for a detailed description of the
351           syntax.
352
353           If the pattern is all lowercase, matching is case insensitive.
354           Otherwise, matching is case sensitive. This can be overridden with
355           the --case-sensitive option, see below.
356
357       --case-sensitive[=BOOLEAN]
358           Make pattern matching case sensitive or case insensitive.
359
360       -c, --cursor=
361           Start showing entries from the location in the journal specified by
362           the passed cursor.
363
364       --cursor-file=FILE
365           If FILE exists and contains a cursor, start showing entries after
366           this location. Otherwise the show entries according the other given
367           options. At the end, write the cursor of the last entry to FILE.
368           Use this option to continually read the journal by sequentially
369           calling journalctl.
370
371       --after-cursor=
372           Start showing entries from the location in the journal after the
373           location specified by the passed cursor. The cursor is shown when
374           the --show-cursor option is used.
375
376       --show-cursor
377           The cursor is shown after the last entry after two dashes:
378
379               -- cursor: s=0639...
380
381           The format of the cursor is private and subject to change.
382
383       -S, --since=, -U, --until=
384           Start showing entries on or newer than the specified date, or on or
385           older than the specified date, respectively. Date specifications
386           should be of the format "2012-10-30 18:17:16". If the time part is
387           omitted, "00:00:00" is assumed. If only the seconds component is
388           omitted, ":00" is assumed. If the date component is omitted, the
389           current day is assumed. Alternatively the strings "yesterday",
390           "today", "tomorrow" are understood, which refer to 00:00:00 of the
391           day before the current day, the current day, or the day after the
392           current day, respectively.  "now" refers to the current time.
393           Finally, relative times may be specified, prefixed with "-" or "+",
394           referring to times before or after the current time, respectively.
395           For complete time and date specification, see systemd.time(7). Note
396           that --output=short-full prints timestamps that follow precisely
397           this format.
398
399       -F, --field=
400           Print all possible data values the specified field can take in all
401           entries of the journal.
402
403       -N, --fields
404           Print all field names currently used in all entries of the journal.
405
406       --system, --user
407           Show messages from system services and the kernel (with --system).
408           Show messages from service of current user (with --user). If
409           neither is specified, show all messages that the user can see.
410
411       -M, --machine=
412           Show messages from a running, local container. Specify a container
413           name to connect to.
414
415       -D DIR, --directory=DIR
416           Takes a directory path as argument. If specified, journalctl will
417           operate on the specified journal directory DIR instead of the
418           default runtime and system journal paths.
419
420       --file=GLOB
421           Takes a file glob as an argument. If specified, journalctl will
422           operate on the specified journal files matching GLOB instead of the
423           default runtime and system journal paths. May be specified multiple
424           times, in which case files will be suitably interleaved.
425
426       --root=ROOT
427           Takes a directory path as an argument. If specified, journalctl
428           will operate on journal directories and catalog file hierarchy
429           underneath the specified directory instead of the root directory
430           (e.g.  --update-catalog will create
431           ROOT/var/lib/systemd/catalog/database, and journal files under
432           ROOT/run/journal/ or ROOT/var/log/journal/ will be displayed).
433
434       --image=IMAGE
435           Takes a path to a disk image file or block device node. If
436           specified, journalctl will operate on the file system in the
437           indicated disk image. This is similar to --root= but operates on
438           file systems stored in disk images or block devices, thus providing
439           an easy way to extract log data from disk images. The disk image
440           should either contain just a file system or a set of file systems
441           within a GPT partition table, following the Discoverable Partitions
442           Specification[6]. For further information on supported disk images,
443           see systemd-nspawn(1)'s switch of the same name.
444
445       --namespace=NAMESPACE
446           Takes a journal namespace identifier string as argument. If not
447           specified the data collected by the default namespace is shown. If
448           specified shows the log data of the specified namespace instead. If
449           the namespace is specified as "*" data from all namespaces is
450           shown, interleaved. If the namespace identifier is prefixed with
451           "+" data from the specified namespace and the default namespace is
452           shown, interleaved, but no other. For details about journal
453           namespaces see systemd-journald.service(8).
454
455       --header
456           Instead of showing journal contents, show internal header
457           information of the journal fields accessed.
458
459       --disk-usage
460           Shows the current disk usage of all journal files. This shows the
461           sum of the disk usage of all archived and active journal files.
462
463       --vacuum-size=, --vacuum-time=, --vacuum-files=
464           Removes the oldest archived journal files until the disk space they
465           use falls below the specified size (specified with the usual "K",
466           "M", "G" and "T" suffixes), or all archived journal files contain
467           no data older than the specified timespan (specified with the usual
468           "s", "m", "h", "days", "months", "weeks" and "years" suffixes), or
469           no more than the specified number of separate journal files remain.
470           Note that running --vacuum-size= has only an indirect effect on the
471           output shown by --disk-usage, as the latter includes active journal
472           files, while the vacuuming operation only operates on archived
473           journal files. Similarly, --vacuum-files= might not actually reduce
474           the number of journal files to below the specified number, as it
475           will not remove active journal files.
476
477           --vacuum-size=, --vacuum-time= and --vacuum-files= may be combined
478           in a single invocation to enforce any combination of a size, a time
479           and a number of files limit on the archived journal files.
480           Specifying any of these three parameters as zero is equivalent to
481           not enforcing the specific limit, and is thus redundant.
482
483           These three switches may also be combined with --rotate into one
484           command. If so, all active files are rotated first, and the
485           requested vacuuming operation is executed right after. The rotation
486           has the effect that all currently active files are archived (and
487           potentially new, empty journal files opened as replacement), and
488           hence the vacuuming operation has the greatest effect as it can
489           take all log data written so far into account.
490
491       --list-catalog [128-bit-ID...]
492           List the contents of the message catalog as a table of message IDs,
493           plus their short description strings.
494
495           If any 128-bit-IDs are specified, only those entries are shown.
496
497       --dump-catalog [128-bit-ID...]
498           Show the contents of the message catalog, with entries separated by
499           a line consisting of two dashes and the ID (the format is the same
500           as .catalog files).
501
502           If any 128-bit-IDs are specified, only those entries are shown.
503
504       --update-catalog
505           Update the message catalog index. This command needs to be executed
506           each time new catalog files are installed, removed, or updated to
507           rebuild the binary catalog index.
508
509       --setup-keys
510           Instead of showing journal contents, generate a new key pair for
511           Forward Secure Sealing (FSS). This will generate a sealing key and
512           a verification key. The sealing key is stored in the journal data
513           directory and shall remain on the host. The verification key should
514           be stored externally. Refer to the Seal= option in journald.conf(5)
515           for information on Forward Secure Sealing and for a link to a
516           refereed scholarly paper detailing the cryptographic theory it is
517           based on.
518
519       --force
520           When --setup-keys is passed and Forward Secure Sealing (FSS) has
521           already been configured, recreate FSS keys.
522
523       --interval=
524           Specifies the change interval for the sealing key when generating
525           an FSS key pair with --setup-keys. Shorter intervals increase CPU
526           consumption but shorten the time range of undetectable journal
527           alterations. Defaults to 15min.
528
529       --verify
530           Check the journal file for internal consistency. If the file has
531           been generated with FSS enabled and the FSS verification key has
532           been specified with --verify-key=, authenticity of the journal file
533           is verified.
534
535       --verify-key=
536           Specifies the FSS verification key to use for the --verify
537           operation.
538
539       --sync
540           Asks the journal daemon to write all yet unwritten journal data to
541           the backing file system and synchronize all journals. This call
542           does not return until the synchronization operation is complete.
543           This command guarantees that any log messages written before its
544           invocation are safely stored on disk at the time it returns.
545
546       --flush
547           Asks the journal daemon to flush any log data stored in
548           /run/log/journal/ into /var/log/journal/, if persistent storage is
549           enabled. This call does not return until the operation is complete.
550           Note that this call is idempotent: the data is only flushed from
551           /run/log/journal/ into /var/log/journal/ once during system runtime
552           (but see --relinquish-var below), and this command exits cleanly
553           without executing any operation if this has already happened. This
554           command effectively guarantees that all data is flushed to
555           /var/log/journal/ at the time it returns.
556
557       --relinquish-var
558           Asks the journal daemon for the reverse operation to --flush: if
559           requested the daemon will write further log data to
560           /run/log/journal/ and stops writing to /var/log/journal/. A
561           subsequent call to --flush causes the log output to switch back to
562           /var/log/journal/, see above.
563
564       --smart-relinquish-var
565           Similar to --relinquish-var but executes no operation if the root
566           file system and /var/lib/journal/ reside on the same mount point.
567           This operation is used during system shutdown in order to make the
568           journal daemon stop writing data to /var/log/journal/ in case that
569           directory is located on a mount point that needs to be unmounted.
570
571       --rotate
572           Asks the journal daemon to rotate journal files. This call does not
573           return until the rotation operation is complete. Journal file
574           rotation has the effect that all currently active journal files are
575           marked as archived and renamed, so that they are never written to
576           in future. New (empty) journal files are then created in their
577           place. This operation may be combined with --vacuum-size=,
578           --vacuum-time= and --vacuum-file= into a single command, see above.
579
580       -h, --help
581           Print a short help text and exit.
582
583       --version
584           Print a short version string and exit.
585
586       --no-pager
587           Do not pipe output into a pager.
588

EXIT STATUS

590       On success, 0 is returned; otherwise, a non-zero failure code is
591       returned.
592

ENVIRONMENT

594       $SYSTEMD_LOG_LEVEL
595           The maximum log level of emitted messages (messages with a higher
596           log level, i.e. less important ones, will be suppressed). Either
597           one of (in order of decreasing importance) emerg, alert, crit, err,
598           warning, notice, info, debug, or an integer in the range 0...7. See
599           syslog(3) for more information.
600
601       $SYSTEMD_LOG_COLOR
602           A boolean. If true, messages written to the tty will be colored
603           according to priority.
604
605           This setting is only useful when messages are written directly to
606           the terminal, because journalctl(1) and other tools that display
607           logs will color messages based on the log level on their own.
608
609       $SYSTEMD_LOG_TIME
610           A boolean. If true, console log messages will be prefixed with a
611           timestamp.
612
613           This setting is only useful when messages are written directly to
614           the terminal or a file, because journalctl(1) and other tools that
615           display logs will attach timestamps based on the entry metadata on
616           their own.
617
618       $SYSTEMD_LOG_LOCATION
619           A boolean. If true, messages will be prefixed with a filename and
620           line number in the source code where the message originates.
621
622           Note that the log location is often attached as metadata to journal
623           entries anyway. Including it directly in the message text can
624           nevertheless be convenient when debugging programs.
625
626       $SYSTEMD_LOG_TID
627           A boolean. If true, messages will be prefixed with the current
628           numerical thread ID (TID).
629
630           Note that the this information is attached as metadata to journal
631           entries anyway. Including it directly in the message text can
632           nevertheless be convenient when debugging programs.
633
634       $SYSTEMD_LOG_TARGET
635           The destination for log messages. One of console (log to the
636           attached tty), console-prefixed (log to the attached tty but with
637           prefixes encoding the log level and "facility", see syslog(3), kmsg
638           (log to the kernel circular log buffer), journal (log to the
639           journal), journal-or-kmsg (log to the journal if available, and to
640           kmsg otherwise), auto (determine the appropriate log target
641           automatically, the default), null (disable log output).
642
643       $SYSTEMD_PAGER
644           Pager to use when --no-pager is not given; overrides $PAGER. If
645           neither $SYSTEMD_PAGER nor $PAGER are set, a set of well-known
646           pager implementations are tried in turn, including less(1) and
647           more(1), until one is found. If no pager implementation is
648           discovered no pager is invoked. Setting this environment variable
649           to an empty string or the value "cat" is equivalent to passing
650           --no-pager.
651
652       $SYSTEMD_LESS
653           Override the options passed to less (by default "FRSXMK").
654
655           Users might want to change two options in particular:
656
657           K
658               This option instructs the pager to exit immediately when Ctrl+C
659               is pressed. To allow less to handle Ctrl+C itself to switch
660               back to the pager command prompt, unset this option.
661
662               If the value of $SYSTEMD_LESS does not include "K", and the
663               pager that is invoked is less, Ctrl+C will be ignored by the
664               executable, and needs to be handled by the pager.
665
666           X
667               This option instructs the pager to not send termcap
668               initialization and deinitialization strings to the terminal. It
669               is set by default to allow command output to remain visible in
670               the terminal even after the pager exits. Nevertheless, this
671               prevents some pager functionality from working, in particular
672               paged output cannot be scrolled with the mouse.
673
674           See less(1) for more discussion.
675
676       $SYSTEMD_LESSCHARSET
677           Override the charset passed to less (by default "utf-8", if the
678           invoking terminal is determined to be UTF-8 compatible).
679
680       $SYSTEMD_PAGERSECURE
681           Takes a boolean argument. When true, the "secure" mode of the pager
682           is enabled; if false, disabled. If $SYSTEMD_PAGERSECURE is not set
683           at all, secure mode is enabled if the effective UID is not the same
684           as the owner of the login session, see geteuid(2) and
685           sd_pid_get_owner_uid(3). In secure mode, LESSSECURE=1 will be set
686           when invoking the pager, and the pager shall disable commands that
687           open or create new files or start new subprocesses. When
688           $SYSTEMD_PAGERSECURE is not set at all, pagers which are not known
689           to implement secure mode will not be used. (Currently only less(1)
690           implements secure mode.)
691
692           Note: when commands are invoked with elevated privileges, for
693           example under sudo(8) or pkexec(1), care must be taken to ensure
694           that unintended interactive features are not enabled. "Secure" mode
695           for the pager may be enabled automatically as describe above.
696           Setting SYSTEMD_PAGERSECURE=0 or not removing it from the inherited
697           environment allows the user to invoke arbitrary commands. Note that
698           if the $SYSTEMD_PAGER or $PAGER variables are to be honoured,
699           $SYSTEMD_PAGERSECURE must be set too. It might be reasonable to
700           completely disable the pager using --no-pager instead.
701
702       $SYSTEMD_COLORS
703           Takes a boolean argument. When true, systemd and related utilities
704           will use colors in their output, otherwise the output will be
705           monochrome. Additionally, the variable can take one of the
706           following special values: "16", "256" to restrict the use of colors
707           to the base 16 or 256 ANSI colors, respectively. This can be
708           specified to override the automatic decision based on $TERM and
709           what the console is connected to.
710
711       $SYSTEMD_URLIFY
712           The value must be a boolean. Controls whether clickable links
713           should be generated in the output for terminal emulators supporting
714           this. This can be specified to override the decision that systemd
715           makes based on $TERM and other conditions.
716

EXAMPLES

718       Without arguments, all collected logs are shown unfiltered:
719
720           journalctl
721
722       With one match specified, all entries with a field matching the
723       expression are shown:
724
725           journalctl _SYSTEMD_UNIT=avahi-daemon.service
726           journalctl _SYSTEMD_CGROUP=/user.slice/user-42.slice/session-c1.scope
727
728       If two different fields are matched, only entries matching both
729       expressions at the same time are shown:
730
731           journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097
732
733       If two matches refer to the same field, all entries matching either
734       expression are shown:
735
736           journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service
737
738       If the separator "+" is used, two expressions may be combined in a
739       logical OR. The following will show all messages from the Avahi service
740       process with the PID 28097 plus all messages from the D-Bus service
741       (from any of its processes):
742
743           journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service
744
745       To show all fields emitted by a unit and about the unit, option
746       -u/--unit= should be used.  journalctl -u name expands to a complex
747       filter similar to
748
749           _SYSTEMD_UNIT=name.service
750             + UNIT=name.service _PID=1
751             + OBJECT_SYSTEMD_UNIT=name.service _UID=0
752             + COREDUMP_UNIT=name.service _UID=0 MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1
753
754
755       (see systemd.journal-fields(7) for an explanation of those patterns).
756
757       Show all logs generated by the D-Bus executable:
758
759           journalctl /usr/bin/dbus-daemon
760
761       Show all kernel logs from previous boot:
762
763           journalctl -k -b -1
764
765       Show a live log display from a system service apache.service:
766
767           journalctl -f -u apache
768

SEE ALSO

770       systemd(1), systemd-journald.service(8), systemctl(1), coredumpctl(1),
771       systemd.journal-fields(7), journald.conf(5), systemd.time(7), systemd-
772       journal-remote.service(8), systemd-journal-upload.service(8)
773

NOTES

775        1. Journal Export Format
776           https://www.freedesktop.org/wiki/Software/systemd/export
777
778        2. Journal JSON Format
779           https://www.freedesktop.org/wiki/Software/systemd/json
780
781        3. Server-Sent Events
782           https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events
783
784        4. JavaScript Object Notation (JSON) Text Sequences
785           https://tools.ietf.org/html/rfc7464
786
787        5. Message Catalog Developer Documentation
788           https://www.freedesktop.org/wiki/Software/systemd/catalog
789
790        6. Discoverable Partitions Specification
791           https://systemd.io/DISCOVERABLE_PARTITIONS
792
793
794
795systemd 249                                                      JOURNALCTL(1)
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