1JOURNALCTL(1)                     journalctl                     JOURNALCTL(1)
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3
4

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. The
59       --header option can be used to identify which files are being shown.
60
61       The set of journal files which will be used can be modified using the
62       --user, --system, --directory, and --file options, see below.
63
64       All users are granted access to their private per-user journals.
65       However, by default, only root and users who are members of a few
66       special groups are granted access to the system journal and the
67       journals of other users. Members of the groups "systemd-journal",
68       "adm", and "wheel" can read all journal files. Note that the two latter
69       groups traditionally have additional privileges specified by the
70       distribution. Members of the "wheel" group can often perform
71       administrative tasks.
72
73       The output is paged through less by default, and long lines are
74       "truncated" to screen width. The hidden part can be viewed by using the
75       left-arrow and right-arrow keys. Paging can be disabled; see the
76       --no-pager option and the "Environment" section below.
77
78       When outputting to a tty, lines are colored according to priority:
79       lines of level ERROR and higher are colored red; lines of level NOTICE
80       and higher are highlighted; lines of level DEBUG are colored lighter
81       grey; other lines are displayed normally.
82

OPTIONS

84       The following options are understood:
85
86       --no-full, --full, -l
87           Ellipsize fields when they do not fit in available columns. The
88           default is to show full fields, allowing them to wrap or be
89           truncated by the pager, if one is used.
90
91           The old options -l/--full are not useful anymore, except to undo
92           --no-full.
93
94       -a, --all
95           Show all fields in full, even if they include unprintable
96           characters or are very long. By default, fields with unprintable
97           characters are abbreviated as "blob data". (Note that the pager may
98           escape unprintable characters again.)
99
100       -f, --follow
101           Show only the most recent journal entries, and continuously print
102           new entries as they are appended to the journal.
103
104       -e, --pager-end
105           Immediately jump to the end of the journal inside the implied pager
106           tool. This implies -n1000 to guarantee that the pager will not
107           buffer logs of unbounded size. This may be overridden with an
108           explicit -n with some other numeric value, while -nall will disable
109           this cap. Note that this option is only supported for the less(1)
110           pager.
111
112       -n, --lines=
113           Show the most recent journal events and limit the number of events
114           shown. If --follow is used, this option is implied. The argument is
115           a positive integer or "all" to disable line limiting. The default
116           value is 10 if no argument is given.
117
118       --no-tail
119           Show all stored output lines, even in follow mode. Undoes the
120           effect of --lines=.
121
122       -r, --reverse
123           Reverse output so that the newest entries are displayed first.
124
125       -o, --output=
126           Controls the formatting of the journal entries that are shown.
127           Takes one of the following options:
128
129           short
130               is the default and generates an output that is mostly identical
131               to the formatting of classic syslog files, showing one line per
132               journal entry.
133
134           short-full
135               is very similar, but shows timestamps in the format the
136               --since= and --until= options accept. Unlike the timestamp
137               information shown in short output mode this mode includes
138               weekday, year and timezone information in the output, and is
139               locale-independent.
140
141           short-iso
142               is very similar, but shows ISO 8601 wallclock timestamps.
143
144           short-iso-precise
145               as for short-iso but includes full microsecond precision.
146
147           short-precise
148               is very similar, but shows classic syslog timestamps with full
149               microsecond precision.
150
151           short-monotonic
152               is very similar, but shows monotonic timestamps instead of
153               wallclock timestamps.
154
155           short-unix
156               is very similar, but shows seconds passed since January 1st
157               1970 UTC instead of wallclock timestamps ("UNIX time"). The
158               time is shown with microsecond accuracy.
159
160           verbose
161               shows the full-structured entry items with all fields.
162
163           export
164               serializes the journal into a binary (but mostly text-based)
165               stream suitable for backups and network transfer (see Journal
166               Export Format[1] for more information). To import the binary
167               stream back into native journald format use systemd-journal-
168               remote(8).
169
170           json
171               formats entries as JSON objects, separated by newline
172               characters (see Journal JSON Format[2] for more information).
173               Field values are generally encoded as JSON strings, with three
174               exceptions:
175
176                1. Fields larger than 4096 bytes are encoded as null values.
177                   (This may be turned off by passing --all, but be aware that
178                   this may allocate overly long JSON objects.)
179
180                2. Journal entries permit non-unique fields within the same
181                   log entry. JSON does not allow non-unique fields within
182                   objects. Due to this, if a non-unique field is encountered
183                   a JSON array is used as field value, listing all field
184                   values as elements.
185
186                3. Fields containing non-printable or non-UTF8 bytes are
187                   encoded as arrays containing the raw bytes individually
188                   formatted as unsigned numbers.
189
190               Note that this encoding is reversible (with the exception of
191               the size limit).
192
193           json-pretty
194               formats entries as JSON data structures, but formats them in
195               multiple lines in order to make them more readable by humans.
196
197           json-sse
198               formats entries as JSON data structures, but wraps them in a
199               format suitable for Server-Sent Events[3].
200
201           json-seq
202               formats entries as JSON data structures, but prefixes them with
203               an ASCII Record Separator character (0x1E) and suffixes them
204               with an ASCII Line Feed character (0x0A), in accordance with
205               JavaScript Object Notation (JSON) Text Sequences[4]
206               ("application/json-seq").
207
208           cat
209               generates a very terse output, only showing the actual message
210               of each journal entry with no metadata, not even a timestamp.
211               If combined with the --output-fields= option will output the
212               listed fields for each log record, instead of the message.
213
214           with-unit
215               similar to short-full, but prefixes the unit and user unit
216               names instead of the traditional syslog identifier. Useful when
217               using templated instances, as it will include the arguments in
218               the unit names.
219
220       --output-fields=
221           A comma separated list of the fields which should be included in
222           the output. This has an effect only for the output modes which
223           would normally show all fields (verbose, export, json, json-pretty,
224           json-sse and json-seq), as well as on cat. For the former, the
225           "__CURSOR", "__REALTIME_TIMESTAMP", "__MONOTONIC_TIMESTAMP", and
226           "_BOOT_ID" fields are always printed.
227
228       --utc
229           Express time in Coordinated Universal Time (UTC).
230
231       --no-hostname
232           Don't show the hostname field of log messages originating from the
233           local host. This switch has an effect only on the short family of
234           output modes (see above).
235
236           Note: this option does not remove occurrences of the hostname from
237           log entries themselves, so it does not prevent the hostname from
238           being visible in the logs.
239
240       -x, --catalog
241           Augment log lines with explanation texts from the message catalog.
242           This will add explanatory help texts to log messages in the output
243           where this is available. These short help texts will explain the
244           context of an error or log event, possible solutions, as well as
245           pointers to support forums, developer documentation, and any other
246           relevant manuals. Note that help texts are not available for all
247           messages, but only for selected ones. For more information on the
248           message catalog, please refer to the Message Catalog Developer
249           Documentation[5].
250
251           Note: when attaching journalctl output to bug reports, please do
252           not use -x.
253
254       -q, --quiet
255           Suppresses all informational messages (i.e. "-- Journal begins at
256           ...", "-- Reboot --"), any warning messages regarding inaccessible
257           system journals when run as a normal user.
258
259       -m, --merge
260           Show entries interleaved from all available journals, including
261           remote ones.
262
263       -b [[ID][±offset]|all], --boot[=[ID][±offset]|all]
264           Show messages from a specific boot. This will add a match for
265           "_BOOT_ID=".
266
267           The argument may be empty, in which case logs for the current boot
268           will be shown.
269
270           If the boot ID is omitted, a positive offset will look up the boots
271           starting from the beginning of the journal, and an
272           equal-or-less-than zero offset will look up boots starting from the
273           end of the journal. Thus, 1 means the first boot found in the
274           journal in chronological order, 2 the second and so on; while -0 is
275           the last boot, -1 the boot before last, and so on. An empty offset
276           is equivalent to specifying -0, except when the current boot is not
277           the last boot (e.g. because --directory was specified to look at
278           logs from a different machine).
279
280           If the 32-character ID is specified, it may optionally be followed
281           by offset which identifies the boot relative to the one given by
282           boot ID. Negative values mean earlier boots and positive values
283           mean later boots. If offset is not specified, a value of zero is
284           assumed, and the logs for the boot given by ID are shown.
285
286           The special argument all can be used to negate the effect of an
287           earlier use of -b.
288
289       --list-boots
290           Show a tabular list of boot numbers (relative to the current boot),
291           their IDs, and the timestamps of the first and last message
292           pertaining to the boot.
293
294       -k, --dmesg
295           Show only kernel messages. This implies -b and adds the match
296           "_TRANSPORT=kernel".
297
298       -t, --identifier=SYSLOG_IDENTIFIER
299           Show messages for the specified syslog identifier
300           SYSLOG_IDENTIFIER.
301
302           This parameter can be specified multiple times.
303
304       -u, --unit=UNIT|PATTERN
305           Show messages for the specified systemd unit UNIT (such as a
306           service unit), or for any of the units matched by PATTERN. If a
307           pattern is specified, a list of unit names found in the journal is
308           compared with the specified pattern and all that match are used.
309           For each unit name, a match is added for messages from the unit
310           ("_SYSTEMD_UNIT=UNIT"), along with additional matches for messages
311           from systemd and messages about coredumps for the specified unit. A
312           match is also added for "_SYSTEMD_SLICE=UNIT", such that if the
313           provided UNIT is a systemd.slice(5) unit, all logs of children of
314           the slice will be shown.
315
316           This parameter can be specified multiple times.
317
318       --user-unit=
319           Show messages for the specified user session unit. This will add a
320           match for messages from the unit ("_SYSTEMD_USER_UNIT=" and
321           "_UID=") and additional matches for messages from session systemd
322           and messages about coredumps for the specified unit. A match is
323           also added for "_SYSTEMD_USER_SLICE=UNIT", such that if the
324           provided UNIT is a systemd.slice(5) unit, all logs of children of
325           the unit will be shown.
326
327           This parameter can be specified multiple times.
328
329       -p, --priority=
330           Filter output by message priorities or priority ranges. Takes
331           either a single numeric or textual log level (i.e. between
332           0/"emerg" and 7/"debug"), or a range of numeric/text log levels in
333           the form FROM..TO. The log levels are the usual syslog log levels
334           as documented in syslog(3), i.e.  "emerg" (0), "alert" (1),
335           "crit" (2), "err" (3), "warning" (4), "notice" (5), "info" (6),
336           "debug" (7). If a single log level is specified, all messages with
337           this log level or a lower (hence more important) log level are
338           shown. If a range is specified, all messages within the range are
339           shown, including both the start and the end value of the range.
340           This will add "PRIORITY=" matches for the specified priorities.
341
342       --facility=
343           Filter output by syslog facility. Takes a comma-separated list of
344           numbers or facility names. The names are the usual syslog
345           facilities as documented in syslog(3).  --facility=help may be used
346           to display a list of known facility names and exit.
347
348       -g, --grep=
349           Filter output to entries where the MESSAGE= field matches the
350           specified regular expression. PERL-compatible regular expressions
351           are used, see pcre2pattern(3) for a detailed description of the
352           syntax.
353
354           If the pattern is all lowercase, matching is case insensitive.
355           Otherwise, matching is case sensitive. This can be overridden with
356           the --case-sensitive option, see below.
357
358       --case-sensitive[=BOOLEAN]
359           Make pattern matching case sensitive or case insensitive.
360
361       -c, --cursor=
362           Start showing entries from the location in the journal specified by
363           the passed cursor.
364
365       --cursor-file=FILE
366           If FILE exists and contains a cursor, start showing entries after
367           this location. Otherwise the show entries according the other given
368           options. At the end, write the cursor of the last entry to FILE.
369           Use this option to continually read the journal by sequentially
370           calling journalctl.
371
372       --after-cursor=
373           Start showing entries from the location in the journal after the
374           location specified by the passed cursor. The cursor is shown when
375           the --show-cursor option is used.
376
377       --show-cursor
378           The cursor is shown after the last entry after two dashes:
379
380               -- cursor: s=0639...
381
382           The format of the cursor is private and subject to change.
383
384       -S, --since=, -U, --until=
385           Start showing entries on or newer than the specified date, or on or
386           older than the specified date, respectively. Date specifications
387           should be of the format "2012-10-30 18:17:16". If the time part is
388           omitted, "00:00:00" is assumed. If only the seconds component is
389           omitted, ":00" is assumed. If the date component is omitted, the
390           current day is assumed. Alternatively the strings "yesterday",
391           "today", "tomorrow" are understood, which refer to 00:00:00 of the
392           day before the current day, the current day, or the day after the
393           current day, respectively.  "now" refers to the current time.
394           Finally, relative times may be specified, prefixed with "-" or "+",
395           referring to times before or after the current time, respectively.
396           For complete time and date specification, see systemd.time(7). Note
397           that --output=short-full prints timestamps that follow precisely
398           this format.
399
400       -F, --field=
401           Print all possible data values the specified field can take in all
402           entries of the journal.
403
404       -N, --fields
405           Print all field names currently used in all entries of the journal.
406
407       --system, --user
408           Show messages from system services and the kernel (with --system).
409           Show messages from service of current user (with --user). If
410           neither is specified, show all messages that the user can see.
411
412       -M, --machine=
413           Show messages from a running, local container. Specify a container
414           name to connect to.
415
416       -D DIR, --directory=DIR
417           Takes a directory path as argument. If specified, journalctl will
418           operate on the specified journal directory DIR instead of the
419           default runtime and system journal paths.
420
421       --file=GLOB
422           Takes a file glob as an argument. If specified, journalctl will
423           operate on the specified journal files matching GLOB instead of the
424           default runtime and system journal paths. May be specified multiple
425           times, in which case files will be suitably interleaved.
426
427       --root=ROOT
428           Takes a directory path as an argument. If specified, journalctl
429           will operate on journal directories and catalog file hierarchy
430           underneath the specified directory instead of the root directory
431           (e.g.  --update-catalog will create
432           ROOT/var/lib/systemd/catalog/database, and journal files under
433           ROOT/run/journal/ or ROOT/var/log/journal/ will be displayed).
434
435       --image=IMAGE
436           Takes a path to a disk image file or block device node. If
437           specified, journalctl will operate on the file system in the
438           indicated disk image. This is similar to --root= but operates on
439           file systems stored in disk images or block devices, thus providing
440           an easy way to extract log data from disk images. The disk image
441           should either contain just a file system or a set of file systems
442           within a GPT partition table, following the Discoverable Partitions
443           Specification[6]. For further information on supported disk images,
444           see systemd-nspawn(1)'s switch of the same name.
445
446       --namespace=NAMESPACE
447           Takes a journal namespace identifier string as argument. If not
448           specified the data collected by the default namespace is shown. If
449           specified shows the log data of the specified namespace instead. If
450           the namespace is specified as "*" data from all namespaces is
451           shown, interleaved. If the namespace identifier is prefixed with
452           "+" data from the specified namespace and the default namespace is
453           shown, interleaved, but no other. For details about journal
454           namespaces see systemd-journald.service(8).
455
456       --header
457           Instead of showing journal contents, show internal header
458           information of the journal fields accessed.
459
460           This option is particularly useful when trying to identify
461           out-of-order journal entries, as happens for example when the
462           machine is booted with the wrong system time.
463
464       --disk-usage
465           Shows the current disk usage of all journal files. This shows the
466           sum of the disk usage of all archived and active journal files.
467
468       --vacuum-size=, --vacuum-time=, --vacuum-files=
469           Removes the oldest archived journal files until the disk space they
470           use falls below the specified size (specified with the usual "K",
471           "M", "G" and "T" suffixes), or all archived journal files contain
472           no data older than the specified timespan (specified with the usual
473           "s", "m", "h", "days", "months", "weeks" and "years" suffixes), or
474           no more than the specified number of separate journal files remain.
475           Note that running --vacuum-size= has only an indirect effect on the
476           output shown by --disk-usage, as the latter includes active journal
477           files, while the vacuuming operation only operates on archived
478           journal files. Similarly, --vacuum-files= might not actually reduce
479           the number of journal files to below the specified number, as it
480           will not remove active journal files.
481
482           --vacuum-size=, --vacuum-time= and --vacuum-files= may be combined
483           in a single invocation to enforce any combination of a size, a time
484           and a number of files limit on the archived journal files.
485           Specifying any of these three parameters as zero is equivalent to
486           not enforcing the specific limit, and is thus redundant.
487
488           These three switches may also be combined with --rotate into one
489           command. If so, all active files are rotated first, and the
490           requested vacuuming operation is executed right after. The rotation
491           has the effect that all currently active files are archived (and
492           potentially new, empty journal files opened as replacement), and
493           hence the vacuuming operation has the greatest effect as it can
494           take all log data written so far into account.
495
496       --list-catalog [128-bit-ID...]
497           List the contents of the message catalog as a table of message IDs,
498           plus their short description strings.
499
500           If any 128-bit-IDs are specified, only those entries are shown.
501
502       --dump-catalog [128-bit-ID...]
503           Show the contents of the message catalog, with entries separated by
504           a line consisting of two dashes and the ID (the format is the same
505           as .catalog files).
506
507           If any 128-bit-IDs are specified, only those entries are shown.
508
509       --update-catalog
510           Update the message catalog index. This command needs to be executed
511           each time new catalog files are installed, removed, or updated to
512           rebuild the binary catalog index.
513
514       --setup-keys
515           Instead of showing journal contents, generate a new key pair for
516           Forward Secure Sealing (FSS). This will generate a sealing key and
517           a verification key. The sealing key is stored in the journal data
518           directory and shall remain on the host. The verification key should
519           be stored externally. Refer to the Seal= option in journald.conf(5)
520           for information on Forward Secure Sealing and for a link to a
521           refereed scholarly paper detailing the cryptographic theory it is
522           based on.
523
524       --force
525           When --setup-keys is passed and Forward Secure Sealing (FSS) has
526           already been configured, recreate FSS keys.
527
528       --interval=
529           Specifies the change interval for the sealing key when generating
530           an FSS key pair with --setup-keys. Shorter intervals increase CPU
531           consumption but shorten the time range of undetectable journal
532           alterations. Defaults to 15min.
533
534       --verify
535           Check the journal file for internal consistency. If the file has
536           been generated with FSS enabled and the FSS verification key has
537           been specified with --verify-key=, authenticity of the journal file
538           is verified.
539
540       --verify-key=
541           Specifies the FSS verification key to use for the --verify
542           operation.
543
544       --sync
545           Asks the journal daemon to write all yet unwritten journal data to
546           the backing file system and synchronize all journals. This call
547           does not return until the synchronization operation is complete.
548           This command guarantees that any log messages written before its
549           invocation are safely stored on disk at the time it returns.
550
551       --flush
552           Asks the journal daemon to flush any log data stored in
553           /run/log/journal/ into /var/log/journal/, if persistent storage is
554           enabled. This call does not return until the operation is complete.
555           Note that this call is idempotent: the data is only flushed from
556           /run/log/journal/ into /var/log/journal/ once during system runtime
557           (but see --relinquish-var below), and this command exits cleanly
558           without executing any operation if this has already happened. This
559           command effectively guarantees that all data is flushed to
560           /var/log/journal/ at the time it returns.
561
562       --relinquish-var
563           Asks the journal daemon for the reverse operation to --flush: if
564           requested the daemon will write further log data to
565           /run/log/journal/ and stops writing to /var/log/journal/. A
566           subsequent call to --flush causes the log output to switch back to
567           /var/log/journal/, see above.
568
569       --smart-relinquish-var
570           Similar to --relinquish-var but executes no operation if the root
571           file system and /var/lib/journal/ reside on the same mount point.
572           This operation is used during system shutdown in order to make the
573           journal daemon stop writing data to /var/log/journal/ in case that
574           directory is located on a mount point that needs to be unmounted.
575
576       --rotate
577           Asks the journal daemon to rotate journal files. This call does not
578           return until the rotation operation is complete. Journal file
579           rotation has the effect that all currently active journal files are
580           marked as archived and renamed, so that they are never written to
581           in future. New (empty) journal files are then created in their
582           place. This operation may be combined with --vacuum-size=,
583           --vacuum-time= and --vacuum-file= into a single command, see above.
584
585       -h, --help
586           Print a short help text and exit.
587
588       --version
589           Print a short version string and exit.
590
591       --no-pager
592           Do not pipe output into a pager.
593

EXIT STATUS

595       On success, 0 is returned; otherwise, a non-zero failure code is
596       returned.
597

ENVIRONMENT

599       $SYSTEMD_LOG_LEVEL
600           The maximum log level of emitted messages (messages with a higher
601           log level, i.e. less important ones, will be suppressed). Either
602           one of (in order of decreasing importance) emerg, alert, crit, err,
603           warning, notice, info, debug, or an integer in the range 0...7. See
604           syslog(3) for more information.
605
606       $SYSTEMD_LOG_COLOR
607           A boolean. If true, messages written to the tty will be colored
608           according to priority.
609
610           This setting is only useful when messages are written directly to
611           the terminal, because journalctl(1) and other tools that display
612           logs will color messages based on the log level on their own.
613
614       $SYSTEMD_LOG_TIME
615           A boolean. If true, console log messages will be prefixed with a
616           timestamp.
617
618           This setting is only useful when messages are written directly to
619           the terminal or a file, because journalctl(1) and other tools that
620           display logs will attach timestamps based on the entry metadata on
621           their own.
622
623       $SYSTEMD_LOG_LOCATION
624           A boolean. If true, messages will be prefixed with a filename and
625           line number in the source code where the message originates.
626
627           Note that the log location is often attached as metadata to journal
628           entries anyway. Including it directly in the message text can
629           nevertheless be convenient when debugging programs.
630
631       $SYSTEMD_LOG_TID
632           A boolean. If true, messages will be prefixed with the current
633           numerical thread ID (TID).
634
635           Note that the this information is attached as metadata to journal
636           entries anyway. Including it directly in the message text can
637           nevertheless be convenient when debugging programs.
638
639       $SYSTEMD_LOG_TARGET
640           The destination for log messages. One of console (log to the
641           attached tty), console-prefixed (log to the attached tty but with
642           prefixes encoding the log level and "facility", see syslog(3), kmsg
643           (log to the kernel circular log buffer), journal (log to the
644           journal), journal-or-kmsg (log to the journal if available, and to
645           kmsg otherwise), auto (determine the appropriate log target
646           automatically, the default), null (disable log output).
647
648       $SYSTEMD_PAGER
649           Pager to use when --no-pager is not given; overrides $PAGER. If
650           neither $SYSTEMD_PAGER nor $PAGER are set, a set of well-known
651           pager implementations are tried in turn, including less(1) and
652           more(1), until one is found. If no pager implementation is
653           discovered no pager is invoked. Setting this environment variable
654           to an empty string or the value "cat" is equivalent to passing
655           --no-pager.
656
657       $SYSTEMD_LESS
658           Override the options passed to less (by default "FRSXMK").
659
660           Users might want to change two options in particular:
661
662           K
663               This option instructs the pager to exit immediately when Ctrl+C
664               is pressed. To allow less to handle Ctrl+C itself to switch
665               back to the pager command prompt, unset this option.
666
667               If the value of $SYSTEMD_LESS does not include "K", and the
668               pager that is invoked is less, Ctrl+C will be ignored by the
669               executable, and needs to be handled by the pager.
670
671           X
672               This option instructs the pager to not send termcap
673               initialization and deinitialization strings to the terminal. It
674               is set by default to allow command output to remain visible in
675               the terminal even after the pager exits. Nevertheless, this
676               prevents some pager functionality from working, in particular
677               paged output cannot be scrolled with the mouse.
678
679           See less(1) for more discussion.
680
681       $SYSTEMD_LESSCHARSET
682           Override the charset passed to less (by default "utf-8", if the
683           invoking terminal is determined to be UTF-8 compatible).
684
685       $SYSTEMD_PAGERSECURE
686           Takes a boolean argument. When true, the "secure" mode of the pager
687           is enabled; if false, disabled. If $SYSTEMD_PAGERSECURE is not set
688           at all, secure mode is enabled if the effective UID is not the same
689           as the owner of the login session, see geteuid(2) and
690           sd_pid_get_owner_uid(3). In secure mode, LESSSECURE=1 will be set
691           when invoking the pager, and the pager shall disable commands that
692           open or create new files or start new subprocesses. When
693           $SYSTEMD_PAGERSECURE is not set at all, pagers which are not known
694           to implement secure mode will not be used. (Currently only less(1)
695           implements secure mode.)
696
697           Note: when commands are invoked with elevated privileges, for
698           example under sudo(8) or pkexec(1), care must be taken to ensure
699           that unintended interactive features are not enabled. "Secure" mode
700           for the pager may be enabled automatically as describe above.
701           Setting SYSTEMD_PAGERSECURE=0 or not removing it from the inherited
702           environment allows the user to invoke arbitrary commands. Note that
703           if the $SYSTEMD_PAGER or $PAGER variables are to be honoured,
704           $SYSTEMD_PAGERSECURE must be set too. It might be reasonable to
705           completely disable the pager using --no-pager instead.
706
707       $SYSTEMD_COLORS
708           Takes a boolean argument. When true, systemd and related utilities
709           will use colors in their output, otherwise the output will be
710           monochrome. Additionally, the variable can take one of the
711           following special values: "16", "256" to restrict the use of colors
712           to the base 16 or 256 ANSI colors, respectively. This can be
713           specified to override the automatic decision based on $TERM and
714           what the console is connected to.
715
716       $SYSTEMD_URLIFY
717           The value must be a boolean. Controls whether clickable links
718           should be generated in the output for terminal emulators supporting
719           this. This can be specified to override the decision that systemd
720           makes based on $TERM and other conditions.
721

EXAMPLES

723       Without arguments, all collected logs are shown unfiltered:
724
725           journalctl
726
727       With one match specified, all entries with a field matching the
728       expression are shown:
729
730           journalctl _SYSTEMD_UNIT=avahi-daemon.service
731           journalctl _SYSTEMD_CGROUP=/user.slice/user-42.slice/session-c1.scope
732
733       If two different fields are matched, only entries matching both
734       expressions at the same time are shown:
735
736           journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097
737
738       If two matches refer to the same field, all entries matching either
739       expression are shown:
740
741           journalctl _SYSTEMD_UNIT=avahi-daemon.service _SYSTEMD_UNIT=dbus.service
742
743       If the separator "+" is used, two expressions may be combined in a
744       logical OR. The following will show all messages from the Avahi service
745       process with the PID 28097 plus all messages from the D-Bus service
746       (from any of its processes):
747
748           journalctl _SYSTEMD_UNIT=avahi-daemon.service _PID=28097 + _SYSTEMD_UNIT=dbus.service
749
750       To show all fields emitted by a unit and about the unit, option
751       -u/--unit= should be used.  journalctl -u name expands to a complex
752       filter similar to
753
754           _SYSTEMD_UNIT=name.service
755             + UNIT=name.service _PID=1
756             + OBJECT_SYSTEMD_UNIT=name.service _UID=0
757             + COREDUMP_UNIT=name.service _UID=0 MESSAGE_ID=fc2e22bc6ee647b6b90729ab34a250b1
758
759
760       (see systemd.journal-fields(7) for an explanation of those patterns).
761
762       Show all logs generated by the D-Bus executable:
763
764           journalctl /usr/bin/dbus-daemon
765
766       Show all kernel logs from previous boot:
767
768           journalctl -k -b -1
769
770       Show a live log display from a system service apache.service:
771
772           journalctl -f -u apache
773

SEE ALSO

775       systemd(1), systemd-journald.service(8), systemctl(1), coredumpctl(1),
776       systemd.journal-fields(7), journald.conf(5), systemd.time(7), systemd-
777       journal-remote.service(8), systemd-journal-upload.service(8)
778

NOTES

780        1. Journal Export Format
781           https://systemd.io/JOURNAL_EXPORT_FORMATS#journal-export-format
782
783        2. Journal JSON Format
784           https://systemd.io/JOURNAL_EXPORT_FORMATS#journal-json-format
785
786        3. Server-Sent Events
787           https://developer.mozilla.org/en-US/docs/Server-sent_events/Using_server-sent_events
788
789        4. JavaScript Object Notation (JSON) Text Sequences
790           https://tools.ietf.org/html/rfc7464
791
792        5. Message Catalog Developer Documentation
793           https://www.freedesktop.org/wiki/Software/systemd/catalog
794
795        6. Discoverable Partitions Specification
796           https://systemd.io/DISCOVERABLE_PARTITIONS
797
798
799
800systemd 250                                                      JOURNALCTL(1)
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