1BTRBK.CONF(5)                    Btrbk Manual                    BTRBK.CONF(5)
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NAME

6       btrbk.conf - btrbk configuration file
7

SYNOPSIS

9       /etc/btrbk.conf
10       /etc/btrbk/btrbk.conf
11

DESCRIPTION

13       The btrbk configuration file specifies which btrfs subvolumes on the
14       filesystem are to be processed, what target subvolumes should be used
15       to create the backups, and where the snapshots should be generated. The
16       retention policy, as well as most other options can be defined either
17       globally or within a section.
18
19       The options specified always apply to the last section encountered,
20       superseding the values set in upper-level sections. This means that
21       global options must be set before any sections are defined.
22
23       Blank lines are ignored. A hash character (#) starts a comment
24       extending until end of line.
25

SECTIONS

27       volume <volume-directory>|<url> (optional)
28           Absolute path pointing to a btrfs file system containing the source
29           subvolume(s) to be backed up. Usually the mount point of a btrfs
30           filesystem mounted with the subvolid=5 option.
31
32       subvolume <subvolume-name>
33           Subvolume to be backed up, relative to the <volume-directory> of
34           the volume section, or absolute if the volume section is omitted.
35           Accepts wildcard character "*".
36
37           Note that if this subvolume is btrfs root (id=5), it needs to have
38           a valid UUID, which is not the case for file systems created with
39           btrfs-progs < 4.16.
40
41       target [send-receive|raw] <target-directory>|<url>
42           Target directory where the backup subvolumes are to be created. The
43           optional target type defaults to “send-receive”, see TARGET TYPES
44           below for details.
45
46           Multiple target sections are allowed, in any context: a target
47           defined in volume or global context will be used for all underlying
48           subvolume sections (hint: run "btrbk list" or "btrbk config print"
49           to see the resulting configuration).
50
51       If a <url> is specified, btrbk actions (shell commands) are executed
52       remotely via ssh, using the SSH Options described below. Accepted
53       formats are:
54
55           ssh://<hostname>[:<port>]/<directory>
56           <hostname>:<directory>
57
58       Where <hostname> is either a host name, an IPv4 address in
59       dotted-decimal form, or an IP literal encapsulated within square
60       brackets (e.g. "[2001:db8::7]").
61
62       If you are connecting to virtual machines, consider configuring several
63       volume sections for a <hostname>, with distinct <port> numbers for each
64       machine.
65

OPTIONS

67       The options described here can be specified in global context as well
68       as volume, subvolume and target sections, unless stated otherwise.
69
70   Basic Options
71       timestamp_format short|long|long-iso
72           Timestamp format used as postfix for new snapshot subvolume names.
73           Defaults to “long”.
74
75           short
76               YYYYMMDD[_N]  (e.g. "20150825", "20150825_1")
77
78           long
79               YYYYMMDD<T>hhmm[_N]  (e.g. "20150825T1531")
80
81           long-iso
82               YYYYMMDD<T>hhmmss&plusmn;hhmm[_N]  (e.g.
83               "20150825T153123+0200")
84
85           Note that a postfix "_N" is appended to the timestamp if a snapshot
86           or backup already exists with the timestamp of current date/time.
87
88           Use “long-iso” if you want to make sure that btrbk never creates
89           ambiguous time stamps (which can happen if multiple snapshots are
90           created during a daylight saving time clock change).
91
92           Note that using “long-iso” has implications on the scheduling, see
93           Reference Time below.
94
95       snapshot_dir <directory>
96           Directory in which the btrfs snapshots are created, relative to
97           <volume-directory> of the volume section, or absolute if the volume
98           section is omitted. Note that btrbk does not automatically create
99           this directory, and the snapshot creation will fail if it is not
100           present.
101
102       snapshot_name <basename>
103           Base name of the created snapshot (and backup). This option is only
104           valid in the subvolume section. Defaults to <subvolume-name>.
105
106       snapshot_create always|onchange|ondemand|no
107           If set to “always”, snapshots are always created. If set to
108           “onchange”, snapshots are only created if the last snapshot is not
109           up-to-date, i.e. the source subvolume has changed (more precisely:
110           the btrfs generation has been increased) since the last snapshot
111           was created. If set to “ondemand”, snapshots are only created if at
112           least one target subvolume is reachable (useful if you are tight on
113           disk space and you only need btrbk for backups to an external disk
114           which is not always connected). If set to “no”, the snapshots are
115           never created (useful if another instance of btrbk is taking care
116           of snapshot creation). Defaults to “always”.
117
118       incremental yes|no|strict
119           If set, incremental backups are created. If set to “strict”,
120           non-incremental (initial) backups are never created, and
121           incremental backups are restricted to related parents (by
122           parent-uuid relationship). Defaults to “yes”.
123
124           Note that even if the parent-uuid chain is broken, snapshots and
125           backups can still share data (which is especially true for backups
126           created with incremental option enabled), and are perfectly
127           suitable as parents for incremental send-receive operations. But as
128           btrbk can not be certain about this, such operations are disallowed
129           in "incremental strict" mode.
130
131       noauto yes|no
132           If set, the context is skipped by all btrbk actions unless
133           explicitly enabled by a matching btrbk <filter> command line
134           argument (e.g. "btrbk run myfilter").
135
136   Grouping Options
137       group <group-name> [<group-name>]...
138           Add the current section (volume, subvolume or target) to
139           user-defined groups, which can be used as filter for most btrbk
140           commands (see btrbk(1) FILTER STATEMENTS). This option can be set
141           multiple times within the same context.
142
143   Retention Policy Options
144       preserve_day_of_week monday|tuesday|...|sunday
145           Defines on what day a snapshot/backup is considered to be a
146           "weekly" backup. Weekly, monthly and yearly backups are preserved
147           on this day of week (see RETENTION POLICY below). Defaults to
148           “sunday”.
149
150       preserve_hour_of_day [0..23]
151           Defines after what time (in full hours since midnight) a
152           snapshot/backup is considered to be a "daily" backup. Daily,
153           weekly, monthly and yearly backups are preserved on this hour (see
154           RETENTION POLICY below). Ignored on snapshots or backups without
155           time information (timestamp_format short). Defaults to “0”.
156
157       snapshot_preserve no|<retention_policy>
158           Set retention policy for snapshots (see RETENTION POLICY below). If
159           set to “no”, preserve snapshots according to snapshot_preserve_min
160           only. Defaults to “no”.
161
162           Note that snapshot_preserve has no effect if snapshot_preserve_min
163           is set to “all” (the default).
164
165       snapshot_preserve_min all|latest|<number>{h,d,w,m,y}
166           Preserve all snapshots for a minimum amount of hours (h), days (d),
167           weeks (w), months (m) or years (y), regardless of how many there
168           are. If set to “all”, preserve all snapshots forever. If set to
169           “latest”, preserve latest snapshot. Defaults to “all”.
170
171       target_preserve no|<retention_policy>
172           Set retention policy for backups (see RETENTION POLICY below). If
173           set to “no”, preserve backups according to target_preserve_min
174           only. Defaults to “no”.
175
176           Note that target_preserve has no effect if target_preserve_min is
177           set to “all” (the default).
178
179       target_preserve_min  all|latest|no|<number>{h,d,w,m,y}
180           Preserve all backups for a minimum amount of hours (h), days (d),
181           weeks (w), months (m) or years (y), regardless of how many there
182           are. If set to “all”, preserve all backups forever. If set to
183           “latest”, always preserve the latest backup (useful in conjunction
184           with "target_preserve no", if you want to keep the latest backup
185           only). If set to “no”, only the backups following the
186           target_preserve policy are created. Defaults to “all”.
187
188       archive_preserve no|<retention_policy>
189           Set retention policy for archives ("btrbk archive" command), with
190           same semantics as target_preserve.
191
192       archive_preserve_min all|latest|no|<number>{h,d,w,m,y}
193           Set retention policy for archives ("btrbk archive" command), with
194           same semantics as target_preserve_min.
195
196       archive_exclude <pattern>
197           Exclude subvolumes matching <pattern> from archiving. The pattern
198           accepts wildcard character "*", and is matched against the end of
199           the pathname.
200
201   SSH Options
202       ssh_identity <file>|no
203           Absolute path to a ssh identity file (private key). If not set, the
204           ssh default is used (see ssh(1), "-i identity_file"). Note that if
205           the identity key is password protected and no authentication agent
206           is used, btrbk will prompt for user input on every connection
207           attempt.
208
209       ssh_user <username>|no
210           Remote username for ssh. Defaults to “root”. Make sure the remote
211           user is able to run "btrfs" with root privileges (see option
212           backend for details). If set to “no”, the ssh default is used.
213
214       ssh_compression yes|no
215           Enables or disables the compression of ssh connections. Defaults to
216           “no”. Note that if stream_compress is enabled, ssh compression will
217           always be disabled for send/receive operations.
218
219       ssh_cipher_spec default|<cipher_spec>
220           Selects the cipher specification for encrypting the session
221           (comma-separated list of ciphers in order of preference). See the
222           "-c cipher_spec" option in ssh(1) for more information. Defaults to
223           “default” (the ciphers specified in ssh_config(5)).
224
225   Data Stream Options
226       stream_compress <compress_command>|no
227           Compress the btrfs send stream before transferring it from/to
228           remote locations. Defaults to “no”. If enabled, make sure that
229           <compress_command> is available on the source and target hosts.
230           Supported <compress_command>: gzip, pigz, bzip2, pbzip2, bzip3, xz,
231           lzo, lz4, zstd.
232
233       stream_compress_level default|<number>
234           Compression level for the specified <compress_command>. Refer to
235           the related man-page for details (usually [1..9], where 1 means
236           fastest compression). Defaults to “default” (the default
237           compression level of <compress_command>).
238
239       stream_compress_long default|<number>
240           Enable long distance matching for the specified <compress_command>.
241           Refer to the related man-page for details. Only supported for
242           "zstd".
243
244       stream_compress_threads default|<number>
245           Number of threads to use for <compress_command>. Only supported for
246           "pigz", "pbzip2", "bzip3", "zstd" and recent versions of "xz".
247
248       stream_compress_adapt default|<number>
249           Enable adaptive compression for <compress_command>. Only supported
250           for "zstd" (version >= 1.3.6).
251
252       stream_buffer <size>|no
253           Add a buffer to the btrfs send stream (locally, on uncompressed
254           data), with a maximum size of <size>. This can give a speed
255           improvement (measured up to 20%) on both local or remote
256           operations, but also increases system load. A suffix of "k", "m",
257           "g", or "%" can be added to <size> to denote kilobytes (*1024),
258           megabytes, gigabytes, or a percentage of total physical memory.
259           Defaults to “no”.
260
261           If enabled, make sure that the "mbuffer" command (at least version
262           20180505) is available on the host running btrbk. As of
263           btrbk-0.29.0, mbuffer(1) is used for both rate_limit and
264           stream_buffer options:
265
266               mbuffer [-m <stream_buffer>] [-r <rate_limit>]
267
268           Note that mbuffer(1) always reads defaults from "/etc/mbuffer.rc"
269           and "~/.mbuffer.rc".
270
271           Leave this option disabled if your main concern is a stable backup
272           process: while recent versions of mbuffer have proven reliable, it
273           is often desirable to keep things simple rather than adding an
274           additional, multi-threaded process to the command pipe.
275
276       stream_buffer_remote <size>|no
277           Add a buffer on remote hosts (either source or target). Defaults to
278           “no”.
279
280           Enable this if you prefer buffering on the remote side, or even on
281           both sides: reasons for this depend on available memory, disk and
282           cpu performance (btrfs send/receive, compression), as well as
283           networking constraints.
284
285       rate_limit <rate>|no
286           Limit the read rate of the btrfs send stream to <rate> bytes per
287           second (locally, on uncompressed send stream). A suffix of "k",
288           "m", "g", or "t" can be added to denote kilobytes (*1024),
289           megabytes, and so on. Defaults to “no”. Note that rate_limit
290           implicitly adds a stream buffer (see stream_buffer option above).
291
292       rate_limit_remote <rate>|no
293           Add rate limit on remote hosts (either source or target). Defaults
294           to “no”. Note that it usually does not make much sense to enable
295           both rate_limit and rate_limit_remote.
296
297   System Options
298       transaction_log <file>|no
299           If set, all transactions (snapshot create, subvolume send-receive,
300           subvolume delete) as well as abort messages are logged to <file>,
301           in a space-separated table format: "localtime type status
302           target_url source_url parent_url message".
303
304       transaction_syslog <facility>|no
305           If set, all transactions (as described in transaction_log above)
306           are logged to syslog. The program name used in the messages is
307           "btrbk". Accepted parameters for <facility>: user, mail, daemon,
308           auth, lpr, news, cron, authpriv, local0..local7.
309
310       lockfile <file>|no
311           Create lockfile <file> on startup; checks lockfile before running
312           any btrfs commands (using perl "flock"), and exits if the lock is
313           held by another btrbk instance. Ignored on dryrun (-n, --dry-run).
314           See also --lockfile command-line option.
315
316       backend <backend>
317           Backend filesystem utilities to be used for btrfs specific
318           operations. Available backends:
319
320           btrfs-progs
321               Default backend, btrfs commands are called as specified in
322               btrfs(8) (e.g. "btrfs subvolume show").
323
324           btrfs-progs-btrbk
325               btrfs commands are separated by a dash instead of a whitespace
326               (e.g. "btrfs-subvolume-show" instead of "btrfs subvolume
327               show"). Useful for setting suid or file capabilities (setcap)
328               on specific btrfs commands, as implemented in
329               https://github.com/digint/btrfs-progs-btrbk.
330
331           btrfs-progs-sudo
332               btrfs commands are prefixed with "sudo -n" (e.g. "sudo -n btrfs
333               subvolume show" instead of "btrfs subvolume show"). Make sure
334               to have appropriate (root) permissions for the "btrfs" command
335               groups as well as the "readlink" and "test" commands in
336               /etc/sudoers.
337
338           btrfs-progs-doas
339               Similar to btrfs-progs-sudo, using prefix "doas -n".
340
341           If you want to set this option for local or remote hosts only, set
342           backend_local or backend_remote (e.g. "backend_remote
343           btrfs-progs-btrbk").
344
345           If you want to set this option for regular (non-root) user only,
346           set backend_local_user.
347
348       compat <compat-option>...
349           Enable compatibility options. Available compat-option:
350
351           busybox
352               Use busybox compatible commands, at the expense of slight
353               overhead while reading filesystem information.
354
355           ignore_receive_errors  *experimental*
356               Tell btrfs-receive(8) to not terminate on errors by setting
357               "--max-errors=0" option. Print warnings instead.
358
359               A known use case for this are target hosts lacking xattr
360               support (e.g. some Synology NAS), while the send-stream
361               contains "lsetxattr" commands. Another case is targets failing
362               to set otime, complaining with "ERROR: attribute 12 requested
363               but not present".
364
365               Note that there is no guarantee that backups created with this
366               option enabled can be restored at all.
367
368           If you want to set this option for local or remote hosts only, set
369           compat_local or compat_remote (e.g. "compat_remote busybox").
370
371       cache_dir <directory>
372           If set, cache extent maps for the "btrbk extents" command.
373
374   Btrfs Specific Options
375       incremental_prefs <list-spec>[:<amount>]...
376           Specify the preferences to determine the best common (correlated)
377           parent and clone sources for incremental backups, by choosing from
378           predefined candidate lists.
379
380           The list-spec defines from what candidate list the next
381           parent/clone-src should be appended to a result list; amount
382           defines how many (e.g. "sro:1 sro:1" is identical to "sro:2"), or
383           all if omitted. Any candidate which is already in the results is
384           dropped.
385
386           The resulting list of subvolumes is then used as parameters for the
387           btrfs-send(8) command: the first for "-p <parent>", all others for
388           "-c <clone-src>".
389
390           Available list-spec (candidate lists = filtered subsets of
391           correlated subvolumes):
392
393           sro,srn
394               All from snapshot_dir matching snapshot_name, with parent_uuid
395               relationship, sorted by btrbk timestamp (o=older n=newer).
396
397           sao,san
398               All from snapshot_dir matching snapshot_name, sorted by btrbk
399               timestamp (o=older n=newer).
400
401           aro,arn
402               All from incremental_resolve, with parent_uuid relationship,
403               sorted by cgen (o=older n=newer).
404
405           Defaults to "sro:1 srn:1 sao:1 san:1 aro:1 arn:1". Note that for
406           most operations the default resolves a single parent, as there
407           usually are no newer snapshots, and all "sro:1 sao:1 aro:1" resolve
408           to the same snapshot.
409
410           Example: "defaults,sao,san,aro,arn" takes the defaults, and adds
411           clone sources for all (!) known candidates on the filesystem.
412
413       incremental_clones yes|no
414           If enabled, btrbk adds "-c <clone-src>" to the btrfs-send(8)
415           command for all correlated subvolumes resolved by
416           incremental_prefs. If disabled, only "-p <parent>" is used.
417           Defaults to “yes”.
418
419       incremental_resolve mountpoint|directory
420           Specifies where to search for the best common parent for
421           incremental backups. If set to “mountpoint”, use parents in the
422           filesystem tree below the mount point of the snapshot and target
423           directory. If set to “directory”, use parents strictly below
424           snapshot/target directories. Set this to “directory” if you get
425           access problems (when not running btrbk as root). Defaults to
426           “mountpoint”.
427
428       btrfs_commit_delete yes|no
429           If set, wait for the transaction commit at the end of each snapshot
430           or backup deletion (sets --commit-each option for "btrfs subvolume
431           delete"). Defaults to “no”.
432
433       send_protocol <number>|no  *experimental*
434           Use btrfs send protocol version N. If enabled on target, btrbk adds
435           "--proto <number>" to the btrfs-send(8) command. Defaults to “no”
436           (btrfs default).
437
438       send_compressed_data yes|no  *experimental*
439           Send data that is compressed on the filesystem directly without
440           decompressing it. This requires protocol version 2 or higher
441           (btrfs-progs >= 5.19), and implies "send_protocol 2". If enabled on
442           target, btrbk adds "--compressed-data" to the btrfs-send(8)
443           command. Defaults to “no” (btrfs default).
444
445       snapshot_qgroup_destroy yes|no  *experimental*
446
447
448       target_qgroup_destroy yes|no  *experimental*
449
450
451       archive_qgroup_destroy yes|no  *experimental*
452           Whenever a subvolume is deleted, also destroy corresponding default
453           qgroup "0/<subvol-id>". Only useful if you have enabled btrfs quota
454           support. See also:
455           https://bugzilla.kernel.org/show_bug.cgi?id=91751
456
457   Informative Options
458       warn_unknown_targets yes|no
459           If set, prints a warning if btrbk encounters a target subvolume at
460           a unknown location (i.e. not following btrbk naming scheme, or
461           outside the target directory). Defaults to “no”.
462

RETENTION POLICY

464       Retention policies are defined individually for snapshots, backups and
465       archives (summarized as "backups" in the following text), using a
466       combination of:
467
468       *_preserve_min all|latest|no|<number>{h,d,w,m,y}
469           Amount of time (duration) in which all backups are preserved.
470
471       *_preserve no|<retention_policy>
472           Schedule (single points in time) for which individual backups are
473           preserved.
474
475       Note that if "preserve_min" is set to “all” (the default), any setting
476       of "preserve" obviously has no effect.
477
478       The format for <retention_policy> is:
479
480           [<hourly>h] [<daily>d] [<weekly>w] [<monthly>m] [<yearly>y]
481
482       hourly
483           Defines how many hours back hourly backups should be preserved. The
484           first backup of an hour is considered an hourly backup.
485
486       daily
487           Defines how many days back daily backups should be preserved. The
488           first backup of a day (starting at preserve_hour_of_day) is
489           considered a daily backup.
490
491       weekly
492           Defines how many weeks back weekly backups should be preserved. The
493           first daily backup created at preserve_day_of_week (or the first
494           backup in this week if none was made on the exact day) is
495           considered as a weekly backup.
496
497       monthly
498           Defines how many months back monthly backups should be preserved.
499           Every first weekly backup in a month is considered a monthly
500           backup.
501
502       yearly
503           Defines for how many years back yearly backups should be preserved.
504           Every first monthly backup in a year is considered a yearly backup.
505
506       Use an asterisk for “all” (e.g. "target_preserve 60d *m" states:
507       "preserve daily backups for 60 days back, and all monthly backups").
508
509       Hint: Run btrbk with the -S, --print-schedule option to get a
510       comprehensive output of the scheduler results.
511
512   Reference Time
513       The local time on the host running btrbk defines the reference time for
514       all date/time calculations, especially for "beginning of a day", and as
515       a consequence for the first daily, weekly, monthly or yearly backups.
516       The local time on remote hosts (ssh source/target) is never used.
517
518       Unless "timestamp_format long-iso" is set, daily backups are preserved
519       at "preserve_hour_of_day" (defaults to midnight) of the respective time
520       zone (and not for "00:00 UTC", which would be "14:00" in Honolulu).
521       This becomes relevant for setups with multiple btrbk instances, e.g.
522       many snapshot-only instances (spread around the world), and a
523       fetch-only instance on the backup server.
524
525       Caveat:
526
527       •   If "timestamp_format long-iso" is set, each btrbk instance on has a
528           different interpretation of "first in day". Make sure to run btrbk
529           with the same time zone on every host, e.g. by setting the TZ
530           environment variable (see tzset(3)).
531

TARGET TYPES

533       send-receive
534           Backup to a btrfs filesystem, using "btrfs send/receive". This is
535           the recommended (standard) target type. The <target-directory> must
536           be an absolute path and point to a subvolume or directory within a
537           btrfs file system. See btrfs-send(8), btrfs-receive(8).
538
539       raw  *experimental*
540           Backup to a raw (filesystem independent) file from the output of
541           btrfs-send(8), with optional compression and encryption.
542
543           Note that the target preserve mechanism is currently disabled for
544           incremental raw backups (btrbk does not delete any incremental raw
545           files)!
546
547           Raw backups consist of two files: the main data file containing the
548           btrfs send stream, and a sidecar file ".info" containing metadata:
549
550               <snapshot-name>.<timestamp>[_N].btrfs[.gz|.bz2|...][.gpg]
551               <snapshot-name>.<timestamp>[_N].btrfs[.gz|.bz2|...][.gpg].info
552
553           For incremental backups ("incremental yes"), please note that:
554
555           •   As soon as a single incremental backup file is lost or
556               corrupted, all later incremental backups become invalid, as
557               there is no common parent for the subsequent incremental images
558               anymore. This might be a good compromise for a vacation backup
559               plan, but for the long term make sure that a non-incremental
560               backup is triggered from time to time.
561
562           •   There is currently no support for rotation of incremental
563               backups: if incremental is set, a full backup must be triggered
564               manually from time to time in order to be able to delete old
565               backups.
566
567           Additional options for raw targets:
568
569           raw_target_compress <compress_command>|no
570               Compression algorithm to use for raw backup target. Supported
571               <compress_command>: gzip, pigz, bzip2, pbzip2, bzip3, xz, lzo,
572               lz4, zstd.
573
574           raw_target_compress_level default|<number>
575               Compression level for the specified <compress_command>.
576
577           raw_target_compress_long default|<number>
578               Enable long distance matching for the specified
579               <compress_command>.
580
581           raw_target_compress_threads default|<number>
582               Number of threads to use for <compress_command>.
583
584           raw_target_split <size>|no
585               Split the raw backup file into pieces of size <size>.
586
587           raw_target_block_size <number>
588               Block size to use for writing the raw backup file. Defaults to
589               “128K”.
590
591           raw_target_encrypt gpg|openssl_enc|no
592               If enabled, encrypt the target raw file using gpg or
593               openssl_enc.
594
595           Additional options for "raw_target_encrypt gpg":
596
597           gpg_keyring <file>
598               Keyring to use for gpg, e.g. "/etc/btrbk/gpg/pubring.kbx".
599
600           gpg_recipient <name>...
601               Encrypt for user id <name> (email address).
602
603           Additional options for "raw_target_encrypt openssl_enc" (very
604           experimental):
605
606           openssl_ciphername <name>
607               Defaults to “aes-256-cbc”.
608
609           openssl_iv_size <size-in-bytes>|no
610               Depends on selected cipher.
611
612           openssl_keyfile <file>|no
613               Point to a key file in hex (absolute path). Example key file
614               creation (256bit key):
615
616                     # dd if=/dev/urandom bs=1 count=32 \
617                       | od -x -A n \
618                       | tr -d "[:space:]" > /path/to/keyfile
619
620           kdf_backend <file>|no
621               KDF backend to be executed, e.g.
622               "/usr/share/btrbk/scripts/kdf_pbkdf2.py".
623
624           kdf_keysize <size-in-bytes>
625               Defaults to “32”.
626
627           kdf_keygen once|each
628               Defaults to “once”.
629

AVAILABILITY

631       Please refer to the btrbk project page https://digint.ch/btrbk/ for
632       further details.
633

SEE ALSO

635       btrbk(1)
636

AUTHOR

638       Axel Burri axel@tty0.ch
639
640
641
642Btrbk 0.32.6                      2023-03-25                     BTRBK.CONF(5)
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