Provided by: duplicity_2.1.4-3ubuntu2_amd64 bug

NAME

       duplicity - Encrypted incremental backup to local or remote storage.

SYNOPSIS

       For detailed descriptions for each action see chapter ACTIONS.

       duplicity [backup|full|incremental] [options] source_directory target_url

       duplicity verify [options] [--compare-data] [--path-to-restore <relpath>] [--time time] source_url
       target_directory

       duplicity collection-status [options] [--file-changed <relpath>] [--show-changes-in-set <index>]
       [--jsonstat]] target_url

       duplicity list-current-files [options] [--time time] target_url

       duplicity [restore] [options] [--path-to-restore <relpath>] [--time time] source_url target_directory

       duplicity remove-older-than <time> [options] [--force] target_url

       duplicity remove-all-but-n-full <count> [options] [--force] target_url

       duplicity remove-all-inc-of-but-n-full <count> [options] [--force] target_url

       duplicity cleanup [options] [--force] target_url

DESCRIPTION

       Duplicity incrementally backs up files and folders into tar-format volumes encrypted with GnuPG and
       places them to a remote (or local) storage backend.  See chapter URL FORMAT for a list of all supported
       backends and how to address them.  Because duplicity uses librsync, incremental backups are space
       efficient and only record the parts of files that have changed since the last backup.  Currently
       duplicity supports deleted files, full Unix permissions, uid/gid, directories, symbolic links, fifos,
       etc., but not hard links.

       If you are backing up the root directory /, remember to --exclude /proc, or else duplicity will probably
       crash on the weird stuff in there.

EXAMPLES

       Here is an example of a backup, using sftp to back up /home/me to some_dir on the other.host machine:

              duplicity /home/me sftp://uid@other.host/some_dir

       If the above is run repeatedly, the first will be a full backup, and subsequent ones will be incremental.
       To force a full backup, use the full action:

              duplicity full /home/me sftp://uid@other.host/some_dir

       or enforcing a full every other time via --full-if-older-than <time> , e.g. a full every month:

              duplicity --full-if-older-than 1M /home/me sftp://uid@other.host/some_dir

       Now suppose we accidentally delete /home/me and want to restore it the way it was at the time of last
       backup:

              duplicity sftp://uid@other.host/some_dir /home/me

       Duplicity enters restore mode because the URL comes before the local directory.  If we wanted to restore
       just the file "Mail/article" in /home/me as it was three days ago into /home/me/restored_file:

              duplicity -t 3D --path-to-restore Mail/article sftp://uid@other.host/some_dir
              /home/me/restored_file

       The following action compares the latest backup with the current files:

              duplicity verify sftp://uid@other.host/some_dir /home/me

       Finally, duplicity recognizes several include/exclude options.  For instance, the following will backup
       the root directory, but exclude /mnt, /tmp, and /proc:

              duplicity --exclude /mnt --exclude /tmp --exclude /proc / file:///usr/local/backup

       Note that in this case the destination is the local directory /usr/local/backup.  The following will
       backup only the /home and /etc directories under root:

              duplicity --include /home --include /etc --exclude '**' / file:///usr/local/backup

       Duplicity can also access a repository via ftp.  If a user name is given, the environment variable
       FTP_PASSWORD is read to determine the password:

              FTP_PASSWORD=mypassword duplicity /local/dir ftp://user@other.host/some_dir

ACTIONS

       Duplicity uses actions, which can be given in long or in short form and finetuned with options.
       The actions 'backup' or 'restore' can be implied from the order local path and remote url are given.
       Other actions need to be given explicitly.  For the rare case that the local path may be a valid
       duplicity action name you may append a '/' to the local path name so it can no longer be mistaken for an
       action.

       NOTE: The following explanations explain some but not all options that can be used in connection with
       that action.  Consult the OPTIONS section for more detailed descriptions.

       backup, bu <folder> <url>
              Perform a backup. Duplicity automatically performs an incremental backup if old signatures can be
              found. Else a new backup chain is started.

       full, fb <folder> <url>
              Perform a full backup. A new backup chain is started even if signatures are available for an
              incremental backup.

       incremental, ib <folder> <url>
              If this is requested an incremental backup will be performed.  Duplicity will abort if no old
              signatures can be found.

       verify, vb [--compare-data] [--time <time>] [--path-to-restore <rel_path>] <url> <local_path>
              Verify tests the integrity of the backup archives at the remote location by downloading each file
              and checking both that it can restore the archive and that the restored file matches the signature
              of that file stored in the backup, i.e. compares the archived file with its hash value from
              archival time. Verify does not actually restore and will not overwrite any local files. Duplicity
              will exit with a non-zero error level if any files do not match the signature stored in the
              archive for that file. On verbosity level 4 or higher, it will log a message for each file that
              differs from the stored signature. Files must be downloaded to the local machine in order to
              compare them.  Verify does not compare the backed-up version of the file to the current local copy
              of the files unless the --compare-data option is used (see below).
              The --path-to-restore option restricts verify to that file or folder.  The --time option allows
              one to select a backup to verify.  The --compare-data option enables data comparison (see below).

       collection-status, st [--file-changed <relpath>] [--show-changes-in-set <index>] <url>
              Summarize the status of the backup repository by printing the chains and sets found, and the
              number of volumes in each.
              The --file-changed option summarizes the changes to the file (in the most recent backup chain).
              The --show-changes-in-set option summarizes all the file changes in the index:th backup set (where
              index 0 means the latest set, 1 means the next to latest, etc.).  --jsonstat prints the changes in
              json format and statistics from the jsonstat files if the backups were created with --jsonstat. If
              <index> is set to -1 statistics for the whole backup chain printed

       list-current-files, ls [--time <time>] <url>
              Lists the files contained in the most current backup or backup at time.  The information will be
              extracted from the signature files, not the archive data itself. Thus the whole archive does not
              have to be downloaded, but on the other hand if the archive has been deleted or corrupted, this
              action will not detect it.

       restore, rb [--path-to-restore <relpath>] [--time <time>] <url> <target_folder>
              You can restore the full monty or selected folders/files from a specific time.  Use the relative
              path as it is printed by list-current-files.  Usually not needed as duplicity enters restore mode
              when it detects that the URL comes before the local folder.

       remove-older-than, ro <time> [--force] <url>
              Delete all backup sets older than the given time.  Old backup sets will not be deleted if backup
              sets newer than time depend on them.  See the TIME FORMATS section for more information.  Note,
              this action cannot be combined with backup or other actions, such as cleanup.  Note also that
              --force will be needed to delete the files instead of just listing them.

       remove-all-but-n-full, ra <count> [--force] <url>
              Delete all backups sets that are older than the count:th last full backup (in other words, keep
              the last count full backups and associated incremental sets).  count must be larger than zero. A
              value of 1 means that only the single most recent backup chain will be kept.  Note that --force
              will be needed to delete the files instead of just listing them.

       remove-all-inc-of-but-n-full, ri <count> [--force] <url>
              Delete incremental sets of all backups sets that are older than the count:th last full backup (in
              other words, keep only old full backups and not their increments).  count must be larger than
              zero. A value of 1 means that only the single most recent backup chain will be kept intact.  Note
              that --force will be needed to delete the files instead of just listing them.

       cleanup, cl [--force] <url>
              Delete the extraneous duplicity files on the given backend.  Non-duplicity files, or files in
              complete data sets will not be deleted.  This should only be necessary after a duplicity session
              fails or is aborted prematurely.  Note that --force will be needed to delete the files instead of
              just listing them.

OPTIONS

       --allow-source-mismatch
              Do not abort on attempts to use the same archive dir or remote backend to back up different
              directories. duplicity will tell you if you need this switch.

       --archive-dir path
              The archive directory.

              NOTE: This option changed in 0.6.0.  The archive directory is now necessary in order to manage
              persistence for current and future enhancements.  As such, this option is now used only to change
              the location of the archive directory.  The archive directory should not be deleted, or duplicity
              will have to recreate it from the remote repository (which may require decrypting the backup
              contents).

              When backing up or restoring, this option specifies that the local archive directory is to be
              created in path.  If the archive directory is not specified, the default will be to create the
              archive directory in ~/.cache/duplicity/.

              The archive directory can be shared between backups to multiple targets, because a subdirectory of
              the archive dir is used for individual backups (see --name ).

              The combination of archive directory and backup name must be unique in order to separate the data
              of different backups.

              The interaction between the --archive-dir and the --name options allows for four possible
              combinations for the location of the archive dir:

              1.     neither specified (default)
                      ~/.cache/duplicity/hash-of-url

              2.     --archive-dir=/arch, no --name
                      /arch/hash-of-url

              3.     no --archive-dir, --name=foo
                      ~/.cache/duplicity/foo

              4.     --archive-dir=/arch, --name=foo
                      /arch/foo

       --asynchronous-upload
              (EXPERIMENTAL) Perform file uploads asynchronously in the background, with respect to volume
              creation. This means that duplicity can upload a volume while, at the same time, preparing the
              next volume for upload. The intended end-result is a faster backup, because the local CPU and your
              bandwidth can be more consistently utilized. Use of this option implies additional need for disk
              space in the temporary storage location; rather than needing to store only one volume at a time,
              enough storage space is required to store two volumes.

       --azure-blob-tier
              Standard storage tier used for backup files (Hot|Cool|Archive).

       --azure-max-single-put-size
              Specify the number of the largest supported upload size where the Azure library makes only one put
              call. If the content size is known and below this value the Azure library will only perform one
              put request to upload one block.  The number is expected to be in bytes.

       --azure-max-block-size
              Specify the number for the block size used by the Azure library to upload blobs if it is split
              into multiple blocks.  The maximum block size the service supports is 104857600 (100MiB) and the
              default is 4194304 (4MiB)

       --azure-max-connections
              Specify the number of maximum connections to transfer one blob to Azure blob size exceeds 64MB.
              The default values is 2.

       --b2-hide-files
              Causes Duplicity to hide files in B2 instead of deleting them. Useful in combination with B2's
              lifecycle rules.

       --backend-retry-delay number
              Specifies the number of seconds that duplicity waits after an error has occurred before attempting
              to repeat the operation.

       --cf-backend backend
              Allows the explicit selection of a cloudfiles backend. Defaults to pyrax.  Alternatively you might
              choose cloudfiles.

       --config-dir path
              Allows selection of duplicity's configuratin dir.  Defaults to ~/.config/duplicity.

       --copy-blocksize kilos
              Allows selection of blocksize in kilobytes to use in copying.  Increasing this may speed copying
              of large files.  Defaults to 128.

       --no-check-remote
              Turn off validation of the remote manifest.  Checking is the default.  No checking will allow you
              to backup without the private key, but will mean that the remote manifest may exist and be
              corrupted, leading to the possibility that the backup might not be recoverable.

       --compare-data
              Enable data comparison of regular files on action verify. This conducts a verify as described
              above to verify the integrity of the backup archives, but additionally compares restored files to
              those in target_directory.  Duplicity will not replace any files in target_directory. Duplicity
              will exit with a non-zero error level if the files do not correctly verify or if any files from
              the archive differ from those in target_directory. On verbosity level 4 or higher, it will log a
              message for each file that differs from its equivalent in target_directory.

       --copy-links
              Resolve symlinks during backup.  Enabling this will resolve & back up the symlink's file/folder
              data instead of the symlink itself, potentially increasing the size of the backup.

       --dry-run
              Calculate what would be done, but do not perform any backend actions

       --encrypt-key key-id
              When backing up, encrypt to the given public key, instead of using symmetric (traditional)
              encryption.  Can be specified multiple times.  The key-id can be given in any of the formats
              supported by GnuPG; see gpg(1), section "HOW TO SPECIFY A USER ID" for details.

       --encrypt-secret-keyring filename
              This option can only be used with --encrypt-key, and changes the path to the secret keyring for
              the encrypt key to filename This keyring is not used when creating a backup. If not specified, the
              default secret keyring is used which is usually located at .gnupg/secring.gpg

       --encrypt-sign-key key-id
              Convenience parameter. Same as --encrypt-key key-id --sign-key key-id.

       --exclude shell_pattern
              Exclude the file or files matched by shell_pattern.  If a directory is matched, then files under
              that directory will also be matched.  See the FILE SELECTION section for more information.

       --exclude-device-files
              Exclude all device files.  This can be useful for security/permissions reasons or if duplicity is
              not handling device files correctly.

       --exclude-filelist filename
              Excludes the files listed in filename, with each line of the filelist interpreted according to the
              same rules as --include and --exclude.  See the FILE SELECTION section for more information.

       --exclude-if-present filename
              Exclude directories if filename is present. Allows the user to specify folders that they do not
              wish to backup by adding a specified file (e.g. ".nobackup") instead of maintaining a
              comprehensive exclude/include list.

       --exclude-older-than time
              Exclude any files whose modification date is earlier than the specified time.  This can be used to
              produce a partial backup that contains only recently changed files. See the TIME FORMATS section
              for more information.

       --exclude-other-filesystems
              Exclude files on file systems (identified by device number) other than the file system the root of
              the source directory is on.

       --exclude-regexp regexp
              Exclude files matching the given regexp.  Unlike the --exclude option, this option does not match
              files in a directory it matches.  See the FILE SELECTION section for more information.

       --files-from filename
              Read a list of files to backup from filename rather than searching the entire backup source
              directory. Operation is otherwise normal, just on the specified subset of the backup source
              directory.

              Files must be specified one per line and relative to the backup source directory. Any absolute
              paths will raise an error. All characters per line are significant and treated as part of the
              path, including leading and trailing whitespace. Lines are separated by newlines or nulls,
              depending on whether the --null-separator switch was given.

              It is not necessary to include the parent directory of listed files, their inclusion is implied.
              However, the content of any explicitly listed directories is not implied. All required files must
              be listed when this option is used.

       --file-prefix prefix
       --file-prefix-manifest prefix
       --file-prefix-archive prefix
       --file-prefix-signature prefix
              Adds a prefix to either all files or only manifest, archive, signature files.  The same set of
              prefixes must be passed in on backup and restore.
              If both global and type-specific prefixes are set, global prefix will go before type-specific
              prefixes.

              See also A NOTE ON FILENAME PREFIXES

       --path-to-restore path
              This option may be given in restore mode, causing only path to be restored instead of the entire
              contents of the backup archive.  path should be given relative to the root of the directory backed
              up.

       --filter-globbing
       --filter-ignorecase
       --filter-literal
       --filter-regexp
       --filter-strictcase
              Change the interpretation of patterns passed to the file selection condition option arguments
              --exclude and --include (and variations thereof, including file lists). These options can appear
              multiple times to switch between shell globbing (default), literal strings, and regular
              expressions, case sensitive (default) or not. The specified interpretation applies for all
              subsequent selection conditions up until the next --filter option.

              See the FILE SELECTION section for more information.

       --full-if-older-than time
              Perform a full backup if an incremental backup is requested, but the latest full backup in the
              collection is older than the given time.  See the TIME FORMATS section for more information.

       --force
              Proceed even if data loss might result.  Duplicity will let the user know when this option is
              required.

       --ftp-passive
              Use passive (PASV) data connections.  The default is to use passive, but to fallback to regular if
              the passive connection fails or times out.

       --ftp-regular
              Use regular (PORT) data connections.

       --gio  Use the GIO backend and interpret any URLs as GIO would.

       --gpg-binary file_path
              Allows you to force duplicity to use file_path as gpg command line binary. Can be an absolute or
              relative file path or a file name.  Default value is 'gpg'. The binary will be localized via the
              PATH environment variable.

       --gpg-options options
              Allows you to pass options to gpg encryption.  The options list should be of the form "--opt1
              --opt2=parm" where the string is quoted and the only spaces allowed are between options.

       --hidden-encrypt-key key-id
              Same as --encrypt-key, but it hides user's key id from encrypted file. It uses the gpg's --hidden-
              recipient command to obfuscate the owner of the backup. On restore, gpg will automatically try all
              available secret keys in order to decrypt the backup. See gpg(1) for more details.

       --ignore-errors
              Try to ignore certain errors if they happen. This option is only intended to allow the restoration
              of a backup in the face of certain problems that would otherwise cause the backup to fail. It is
              not ever recommended to use this option unless you have a situation where you are trying to
              restore from backup and it is failing because of an issue which you want duplicity to ignore. Even
              then, depending on the issue, this option may not have an effect.

              Please note that while ignored errors will be logged, there will be no summary at the end of the
              operation to tell you what was ignored, if anything. If this is used for emergency restoration of
              data, it is recommended that you run the backup in such a way that you can revisit the backup log
              (look for lines containing the string IGNORED_ERROR).

              If you ever have to use this option for reasons that are not understood or understood but not your
              own responsibility, please contact duplicity maintainers. The need to use this option under
              production circumstances would normally be considered a bug.

       --imap-full-address email_address
              The full email address of the user name when logging into an imap server.  If not supplied just
              the user name part of the email address is used.

       --imap-mailbox option
              Allows you to specify a different mailbox.  The default is "INBOX".  Other languages may require a
              different mailbox than the default.

       --idr-fakeroot
              idrived uses the concept of a "fakeroot" directory, defined via the --idr-fakeroot=... switch.
              This can be an existing directory, or the directory is created at runtime on the root of the
              (host) files system. (caveat: you have to have write access to the root!). Directories created at
              runtime are auto-removed on exit!
              So, in the above scheme, we could do:
                  duplicity --idr-fakeroot=nicepath idrived://DUPLICITY
              our files end-up at
                  <MYBUCKET>/DUPLICITY/nicepath

       --idr-fakeroot
              idrived uses the concept of a "fakeroot" directory, defined via the --idr-fakeroot=... switch.
              This can be an existing directory, or the directory is created at runtime on the root of the
              (host) files system. (caveat: you have to have write access to the root!). Directories created at
              runtime are auto-removed on exit!
              So, in the above scheme, we could do:
                  duplicity --idr-fakeroot=nicepath idrived://DUPLICITY
              our files end-up at
                  <MYBUCKET>/DUPLICITY/nicepath

       --include shell_pattern
              Similar to --exclude but include matched files instead.  Unlike --exclude, this option will also
              match parent directories of matched files (although not necessarily their contents).  See the FILE
              SELECTION section for more information.

       --include-filelist filename
              Like --exclude-filelist, but include the listed files instead.  See the FILE SELECTION section for
              more information.

       --include-regexp regexp
              Include files matching the regular expression regexp.  Only files explicitly matched by regexp
              will be included by this option.  See the FILE SELECTION section for more information.

       --jsonstat
              Record statistic data similar to the default stats printed at the end of a backup job, addtional
              it includes some meta data about the backup chain e.g. when the full backup was created and how
              many incremental backups were made before.  Output format is json. It written to stdout at notice
              level (as classic stats) and the statistics are kept as a separte file next to the manifest but
              with "jsonstat" as extension.  collection-status --show-changes-in-set <index> --jsonstat adds
              data collected in the backup job and switch the output format to json.  If <index> is set to -1
              statistics for the whole backup chain are printed.

       --log-fd number
              Write specially-formatted versions of output messages to the specified file descriptor.  The
              format used is designed to be easily consumable by other programs.

       --log-file filename
              Write specially-formatted versions of output messages to the specified file.  The format used is
              designed to be easily consumable by other programs.

       --log-timestamp
              Write the log with timestamp and log level before the message, similar to syslog.

       --max-blocksize number
              determines the number of the blocks examined for changes during the diff process.  For files < 1MB
              the blocksize is a constant of 512.  For files over 1MB the size is given by:
                  file_blocksize = int((file_len / (2000 * 512)) * 512)
                  return min(file_blocksize, config.max_blocksize) where config.max_blocksize defaults to 2048.

              If you specify a larger max_blocksize, your difftar files will be larger, but your sigtar files
              will be smaller.  If you specify a smaller max_blocksize, the reverse occurs.  The --max-blocksize
              option should be in multiples of 512.

       --mf-purge
              Option for mediafire to purge files on delete instead of sending to trash.

       --mp-segment-size megs
              Swift backend segment size in megabytes

       --name symbolicname
              Set the symbolic name of the backup being operated on. The intent is to use a separate name for
              each logically distinct backup. For example, someone may use "home_daily_s3" for the daily backup
              of a home directory to Amazon S3. The structure of the name is up to the user, it is only
              important that the names be distinct. The symbolic name is currently only used to affect the
              expansion of --archive-dir , but may be used for additional features in the future. Users running
              more than one distinct backup are encouraged to use this option.

              If not specified, the default value is a hash of the backend URL.

       --no-check-remote
              Turn off validation of the remote manifest.  Checking is the default.  No checking will allow you
              to backup without the private key, but will mean that the remote manifest may exist and be
              corrupted, leading to the possibility that the backup might not be recoverable.

       --no-compression
              Do not use GZip to compress files on remote system.

       --no-encryption
              Do not use GnuPG to encrypt files on remote system.

       --no-print-statistics
              By default duplicity will print statistics about the current session after a successful backup.
              This switch disables that behavior.

       --no-files-changed
              By default duplicity will collect file names and change action in memory (add, del, chg) during
              backup.  This can be quite expensive in memory use, especially with millions of small files.  This
              flag turns off that collection.  This means that the --file-changed option for collection-status
              will return nothing.

       --null-separator
              Use nulls (\0) instead of newlines (\n) as line separators, which may help when dealing with
              filenames containing newlines.  This affects the expected format of the files specified by the
              --{include|exclude}-filelist switches and the --{files-from} option, as well as the format of the
              directory statistics file.

       --numeric-owner
              On restore always use the numeric uid/gid from the archive and not the archived user/group names,
              which is the default behaviour.  Recommended for restoring from live cds which might have the
              users with identical names but different uids/gids.

       --no-restore-ownership
              Ignores the uid/gid from the archive and keeps the current user's one.  Recommended for restoring
              data to mounted filesystem which do not support Unix ownership or when root privileges are not
              available.

       --num-retries number
              Number of retries to make on errors before giving up.

       --par2-options options
              Verbatim options to pass to par2.

       --par2-redundancy percent
              Adjust the level of redundancy in percent for Par2 recovery files (default 10%).

       --par2-volumes number
              Number of Par2 volumes to create (default 1).

       --progress
              When selected, duplicity will output the current upload progress and estimated upload time. To
              annotate changes, it will perform a first dry-run before a full or incremental, and then runs the
              real operation estimating the real upload progress.

       --progress-rate number
              Sets the update rate at which duplicity will output the upload progress messages (requires
              --progress option). Default is to print the status each 3 seconds.

       --rename <original path> <new path>
              Treats the path orig in the backup as if it were the path new.  Can be passed multiple times. An
              example:

              duplicity restore --rename Documents/metal Music/metal sftp://uid@other.host/some_dir /home/me

       --rsync-options options
              Allows you to pass options to the rsync backend.  The options list should be of the form
              "opt1=parm1 opt2=parm2" where the option string is quoted and the only spaces allowed are between
              options. The option string will be passed verbatim to rsync, after any internally generated option
              designating the remote port to use. Here is a possibly useful example:

              duplicity --rsync-options="--partial-dir=.rsync-partial" /home/me rsync://uid@other.host/some_dir

       --s3-endpoint-url url
              Specifies the endpoint URL of the S3 storage.

       --s3-multipart-chunk-size
              Chunk size (in MB, default is 20MB) used for S3 multipart uploads. Adjust this to maximize
              bandwidth usage. For example, a chunk size of 10MB and a volsize of 100MB would result in 10
              chunks per volume upload.

              NOTE: This value should optimally be an even multiple of your --volsize for optimal performance.

              See also A NOTE ON AMAZON S3 below.

       --s3-multipart-max-procs
              Maximum number of concurrent uploads when performing a multipart upload.  The default is 4. You
              can adjust this number to maximizing bandwidth and CPU utilization.

              NOTE: Too many concurrent uploads may have diminishing returns.

              See also A NOTE ON AMAZON S3 below.

       --s3-region-name
              Specifies the region of the S3 storage. Usually mandatory if the bucket is created in a specific
              region.

       --s3-unencrypted-connection
              Disable SSL for connections to S3. This may be much faster, at some cost to confidentiality.

              With this option set, anyone between your computer and S3 can observe the traffic and will be able
              to tell: that you are using Duplicity, the name of the bucket, your AWS Access Key ID, the
              increment dates and the amount of data in each increment.

              This option affects only the connection, not the GPG encryption of the backup increment files.
              Unless that is disabled, an observer will not be able to see the file names or contents.

              See also A NOTE ON AMAZON S3 below.

       --s3-use-deep-archive
              Store volumes using Glacier Deep Archive S3 when uploading to Amazon S3. This storage class has a
              lower cost of storage but a higher per-request cost along with delays of up to 48 hours from the
              time of retrieval request. This storage cost is calculated against a 180-day storage minimum.
              According to Amazon this storage is ideal for data archiving and long-term backup offering
              99.999999999% durability.  To restore a backup you will have to manually migrate all data stored
              on AWS Glacier Deep Archive back to Standard S3 and wait for AWS to complete the migration.

              NOTE: Duplicity will store the manifest.gpg and sigtar.gpg files from full and incremental backups
              on AWS S3 standard storage to allow quick retrieval for later incremental backups, all other data
              is stored in S3 Glacier Deep Archive.

       --s3-use-glacier
              Store volumes using Glacier Flexible Storage when uploading to Amazon S3. This storage class has a
              lower cost of storage but a higher per-request cost along with delays of up to 12 hours from the
              time of retrieval request. This storage cost is calculated against a 90-day storage minimum.
              According to Amazon this storage is ideal for data archiving and long-term backup offering
              99.999999999% durability.  To restore a backup you will have to manually migrate all data stored
              on AWS Glacier back to Standard S3 and wait for AWS to complete the migration.

              NOTE: Duplicity will store the manifest.gpg and sigtar.gpg files from full and incremental backups
              on AWS S3 standard storage to allow quick retrieval for later incremental backups, all other data
              is stored in S3 Glacier.

       --s3-use-glacier-ir
              Store volumes using Glacier Instant Retrieval when uploading to Amazon S3. This storage class is
              similar to Glacier Flexible Storage but offers instant retrieval at standard speeds.

              NOTE: Duplicity will store the manifest.gpg and sigtar.gpg files from full and incremental backups
              on AWS S3 standard storage to allow quick retrieval for later incremental backups, all other data
              is stored in S3 Glacier.

       --s3-use-ia
              Store volumes using Standard - Infrequent Access when uploading to Amazon S3.  This storage class
              has a lower storage cost but a higher per-request cost, and the storage cost is calculated against
              a 30-day storage minimum. According to Amazon, this storage is ideal for long-term file storage,
              backups, and disaster recovery.

       --s3-use-onezone-ia
              Store volumes using One Zone - Infrequent Access when uploading to Amazon S3.  This storage is
              similar to Standard - Infrequent Access, but only stores object data in one Availability Zone.

       --s3-use-rrs
              Store volumes using Reduced Redundancy Storage when uploading to Amazon S3.  This will lower the
              cost of storage but also lower the durability of stored volumes to 99.99% instead the
              99.999999999% durability offered by Standard Storage on S3.

       --s3-use-server-side-kms-encryption
       --s3-kms-key-id key_id
       --s3-kms-grant grant
              Enable server-side encryption using key management service.

       --skip-if-no-change command
              By default an empty incremental backup is created if no files have changed.  Setting this option
              will skip creating a backup if no data has changed.  Nothing will be sent to the target nor
              information be cached.

       --scp-command command
              (only ssh pexpect backend with --use-scp enabled)
              The command will be used instead of "scp" to send or receive files.  To list and delete existing
              files, the sftp command is used.
              See also A NOTE ON SSH BACKENDS section SSH pexpect backend.

       --sftp-command command
              (only ssh pexpect backend)
              The command will be used instead of "sftp".
              See also A NOTE ON SSH BACKENDS section SSH pexpect backend.

       --sign-key key-id
              This option can be used when backing up, restoring or verifying.  When backing up, all backup
              files will be signed with keyid key.  When restoring, duplicity will signal an error if any remote
              file is not signed with the given key-id. The key-id can be given in any of the formats supported
              by GnuPG; see gpg(1), section "HOW TO SPECIFY A USER ID" for details.  Should be specified only
              once because currently only one signing key is supported. Last entry overrides all other entries.
              See also A NOTE ON SYMMETRIC ENCRYPTION AND SIGNING

       --ssh-askpass
              Tells the ssh backend to prompt the user for the remote system password, if it was not defined in
              target url and no FTP_PASSWORD env var is set.  This password is also used for passphrase-
              protected ssh keys.

       --ssh-options options
              Allows you to pass options to the ssh backend.  Can be specified multiple times or as a space
              separated options list.  The options list should be of the form "-oOpt1='parm1' -oOpt2='parm2'"
              where the option string is quoted and the only spaces allowed are between options. The option
              string will be passed verbatim to both scp and sftp, whose command line syntax differs slightly
              hence the options should therefore be given in the long option format described in ssh_config(5).

              example of a list:

                  duplicity --ssh-options="-oProtocol=2 -oIdentityFile='/my/backup/id'" /home/me
              scp://user@host/some_dir

              example with multiple parameters:

                  duplicity --ssh-options="-oProtocol=2" --ssh-options="-oIdentityFile='/my/backup/id'" /home/me
              scp://user@host/some_dir

              NOTE: The ssh paramiko backend currently supports only the -i or -oIdentityFile or
              -oUserKnownHostsFile or -oGlobalKnownHostsFile settings. If needed provide more host specific
              options via ssh_config file.

       --ssl-cacert-file file
              (only webdav & lftp backend) Provide a cacert file for ssl certificate verification.

              See also A NOTE ON SSL CERTIFICATE VERIFICATION.

       --ssl-cacert-path path/to/certs/
              (only webdav backend and python 2.7.9+ OR lftp+webdavs and a recent lftp) Provide a path to a
              folder containing cacert files for ssl certificate verification.

              See also A NOTE ON SSL CERTIFICATE VERIFICATION.

       --ssl-no-check-certificate
              (only webdav & lftp backend) Disable ssl certificate verification.

              See also A NOTE ON SSL CERTIFICATE VERIFICATION.

       --swift-storage-policy
              Use this storage policy when operating on Swift containers.

              See also A NOTE ON SWIFT (OPENSTACK OBJECT STORAGE) ACCESS.

       --metadata-sync-mode mode
              This option defaults to 'partial', but you can set it to 'full'

              Use 'partial' to avoid syncing metadata for backup chains that you are not going to use.  This
              saves time when restoring for the first time, and lets you restore an old backup that was
              encrypted with a different passphrase by supplying only the target passphrase.

              Use 'full' to sync metadata for all backup chains on the remote.

       --tempdir directory
              Use this existing directory for duplicity temporary files instead of the system default, which is
              usually the /tmp directory. This option supersedes any environment variable.

              See also ENVIRONMENT VARIABLES.

       -t time, --time time, --restore-time time
              Specify the time from which to restore or list files.

              See section TIME FORMATS for details.

       --time-separator char
              Use char as the time separator in filenames instead of colon (":").

              NOTE: This option only applies to recovery and status style actions.  We no longer create or write
              filenames with time separators, but will read older backups that may need this option.

       --timeout seconds
              Use seconds as the socket timeout value if duplicity begins to timeout during network operations.
              The default is 30 seconds.

       --use-agent
              If this option is specified, then --use-agent is passed to the GnuPG encryption process and it
              will try to connect to gpg-agent before it asks for a passphrase for --encrypt-key or --sign-key
              if needed.

              NOTE: Contrary to previous versions of duplicity, this option will also be honored by GnuPG 2 and
              newer versions. If GnuPG 2 is in use, duplicity passes the option --pinentry-mode=loopback to the
              the gpg process unless --use-agent is specified on the duplicity command line. This has the effect
              that GnuPG 2 uses the agent only if --use-agent is given, just like GnuPG 1.

       --verbosity level, -vlevel
              Specify output verbosity level (log level).  Named levels and corresponding values are 0 Error, 2
              Warning, 4 Notice (default), 8 Info, 9 Debug (noisiest).
              level may also be
                     a character: e, w, n, i, d
                     a word: error, warning, notice, info, debug

              The options -v4, -vn and -vnotice are functionally equivalent, as are the mixed/upper-case
              versions -vN, -vNotice and -vNOTICE.

       --version
              Print duplicity's version and quit.

       --volsize number
              Change the volume size to number MB. Default is 200MB.

       --webdav-headers csv formatted key,value pairs
              The input format is comma separated list of key,value pairs. Standard CSV encoding may be used.

              For example to set a Cookie use 'Cookie,name=value', or '"Cookie","name=value"'.

              You can set multiple headers, e.g. '"Cookie","name=value","Authorization","xxx"'.

ENVIRONMENT VARIABLES

       TMPDIR, TEMP, TMP
              In decreasing order of importance, specifies the directory to use for temporary files (inherited
              from Python's tempfile module).  Eventually the option --tempdir supersedes any of these.

       FTP_PASSWORD
              Supported by most backends which are password capable. More secure than setting it in the backend
              url (which might be readable in the operating systems process listing to other users on the same
              machine).

       PASSPHRASE
              This passphrase is passed to GnuPG. If this is not set, the user will be prompted for the
              passphrase.  GPG uses the AES encryption method for passphrase encryption.

       SIGN_PASSPHRASE
              The passphrase to be used for --sign-key.  If omitted and sign key is also one of the keys to
              encrypt against PASSPHRASE will be reused instead.  Otherwise, if passphrase is needed but not set
              the user will be prompted for it.  GPG uses the AES encryption method for passphrase encryption.

              Other environment variables may be used to configure specific backends.  See the notes for the
              particular backend.

URL FORMAT

       Duplicity uses the URL format (as standard as possible) to define data locations.  Major difference is
       that the whole host section is optional for some backends.
       NOTE: If path starts with an extra '/' it usually denotes an absolute path on the backend.

       The generic format for a URL is:

              scheme://[[user[:password]@]host[:port]/][/]path

       or

              scheme://[/]path

       It is not recommended to expose the password on the command line since it could be revealed to anyone
       with permissions to do process listings, it is permitted however.  Consider setting the environment
       variable FTP_PASSWORD instead, which is used by most, if not all backends, regardless of it's name.

       In protocols that support it, the path may be preceded by a single slash, '/path', to represent a
       relative path to the target home directory, or preceded by a double slash, '//path', to represent an
       absolute filesystem path.

       NOTE: Scheme (protocol) access may be provided by more than one backend.  In case the default backend is
       buggy or simply not working in a specific case it might be worth trying an alternative implementation.
       Alternative backends can be selected by prefixing the scheme with the name of the alternative backend
       e.g. ncftp+ftp:// and are mentioned below the scheme's syntax summary.

       Formats of each of the URL schemes follow:

       Amazon Drive Backend
              ad://some_dir

              See also A NOTE ON AMAZON DRIVE

       Azure
              azure://container-name

              See also A NOTE ON AZURE ACCESS

       B2
              b2://account_id[:application_key]@bucket_name/[folder/]

       Box
              box:///some_dir[?config=path_to_config]

              See also A NOTE ON BOX ACCESS

       Cloud Files (Rackspace)
              cf+http://container_name

              See also A NOTE ON CLOUD FILES ACCESS

       Dropbox
              dpbx:///some_dir

              Make sure to read A NOTE ON DROPBOX ACCESS first!

       File (local file system)
              file://[relative|/absolute]/local/path

       FISH (Files transferred over Shell protocol) over ssh
              fish://user[:pwd]@other.host[:port]/[relative|/absolute]_path

       FTP
              ftp[s]://user[:password]@other.host[:port]/some_dir

              NOTE: use lftp+, ncftp+ prefixes to enforce a specific backend, default is lftp+ftp://...

       Google Cloud Storage (GCS via Interoperable Access)
              s3://bucket[/path]

              See A NOTE ON GOOGLE CLOUD STORAGE about needed endpoint option and env vars for authentication.

       Google Docs
              gdocs://user[:password]@other.host/some_dir

              NOTE: use pydrive+, gdata+ prefixes to enforce a specific backend, default is pydrive+gdocs://...

       Google Drive

              gdrive://<service account' email address>@developer.gserviceaccount.com/some_dir

              See also A NOTE ON GDRIVE BACKEND below.

       HSI
              hsi://user[:password]@other.host/some_dir

       hubiC
              cf+hubic://container_name

              See also A NOTE ON HUBIC

       IMAP email storage
              imap[s]://user[:password]@host.com[/from_address_prefix]

              See also A NOTE ON IMAP

       MediaFire
              mf://user[:password]@mediafire.com/some_dir

              See also A NOTE ON MEDIAFIRE BACKEND below.

       MEGA.nz cloud storage (only works for accounts created prior to November 2018, uses "megatools")
              mega://user[:password]@mega.nz/some_dir

              NOTE: if not given in the URL, relies on password being stored within $HOME/.megarc (as used by
              the "megatools" utilities)

       MEGA.nz cloud storage (works for all MEGA accounts, uses "MEGAcmd" tools)
              megav2://user[:password]@mega.nz/some_dir megav3://user[:password]@mega.nz/some_dir[?no_logout=1]
              (For latest MEGAcmd)

              NOTE: despite "MEGAcmd" no longer uses a configuration file, for convenience storing the user
              password this backend searches it in the $HOME/.megav2rc file (same syntax as the old
              $HOME/.megarc)
                  [Login]
                  Username = MEGA_USERNAME
                  Password = MEGA_PASSWORD

       multi
              multi:///path/to/config.json

              See also A NOTE ON MULTI BACKEND below.

       OneDrive Backend
              onedrive://some_dir See also A NOTE ON ONEDRIVE BACKEND

       Par2 Wrapper Backend
              par2+scheme://[user[:password]@]host[:port]/[/]path

              See also A NOTE ON PAR2 WRAPPER BACKEND

       Public Cloud Archive (OVH)
              pca://container_name[/prefix]

              See also A NOTE ON PCA ACCESS

       pydrive
              pydrive://<service account' email address>@developer.gserviceaccount.com/some_dir

              See also A NOTE ON PYDRIVE BACKEND below.

       Rclone Backend
              rclone://remote:/some_dir

       See also A NOTE ON RCLONE BACKEND

       Rsync via daemon
              rsync://user[:password]@host.com[:port]::[/]module/some_dir

       Rsync over ssh (only key auth)
              rsync://user@host.com[:port]/[relative|/absolute]_path

       S3 storage (Amazon)
              s3:///bucket_name[/path]

              See also A NOTE ON AMAZON S3 below.

       SCP/SFTP Secure Copy Protocol/SSH File Transfer Protocol
              scp://.. or
              sftp://user[:pwd]@other.host[:port]/[relative|/absolute]_path

              defaults are paramiko+scp:// and paramiko+sftp://
              alternatively try pexpect+scp://, pexpect+sftp://, lftp+sftp://
              See also --ssh-askpass, --ssh-options and A NOTE ON SSH BACKENDS.

       slate
              slate://[slate-id]

              See also A NOTE ON SLATE BACKEND

       Swift (Openstack)
              swift://container_name[/prefix]

              See also A NOTE ON SWIFT (OPENSTACK OBJECT STORAGE) ACCESS

       Tahoe-LAFS
              tahoe://alias/directory

       WebDAV
              webdav[s]://user[:password]@other.host[:port]/some_dir

              alternatively try lftp+webdav[s]://

       Optical media (ISO9660 CD/DVD/Bluray using xorriso)
              xorriso:///dev/byOpticalDrive[:/path/to/directory/on/iso]
              xorriso:///path/to/image.iso[:/path/to/directory/on/iso]

              See also A NOTE ON THE XORRISO BACKEND

TIME FORMATS

       duplicity uses time strings in two places.  Firstly, many of the files duplicity creates will have the
       time in their filenames in the w3 datetime format as described in a w3 note at http://www.w3.org/TR/NOTE-
       datetime.  Basically they look like "2001-07-15T04:09:38-07:00", which means what it looks like.  The
       "-07:00" section means the time zone is 7 hours behind UTC.
       Secondly, the -t, --time, and --restore-time options take a time string, which can be given in any of
       several formats:
       1.     the string "now" (refers to the current time)
       2.     a sequences of digits, like "123456890" (indicating the time in seconds after the epoch)
       3.     A string like "2002-01-25T07:00:00+02:00" in datetime format
       4.     An interval, which is a number followed by one of the characters s, m, h, D, W, M, or Y
              (indicating seconds, minutes, hours, days, weeks, months, or years respectively), or a series of
              such pairs.  In this case the string refers to the time that preceded the current time by the
              length of the interval.  For instance, "1h78m" indicates the time that was one hour and 78 minutes
              ago.  The calendar here is unsophisticated: a month is always 30 days, a year is always 365 days,
              and a day is always 86400 seconds.
       5.     A date format of the form YYYY/MM/DD, YYYY-MM-DD, MM/DD/YYYY, or MM-DD-YYYY, which indicates
              midnight on the day in question, relative to the current time zone settings.  For instance,
              "2002/3/5", "03-05-2002", and "2002-3-05" all mean March 5th, 2002.

FILE SELECTION

       When duplicity is run, it searches through the given source directory and backs up all the files
       specified by the file selection system, unless --files-from has been specified in which case the passed
       list of individual files is used instead.

       The file selection system comprises a number of file selection conditions, which are set using one of the
       following command line options:

              --exclude
              --exclude-device-files
              --exclude-if-present
              --exclude-filelist
              --exclude-regexp
              --include
              --include-filelist
              --include-regexp

       For each individual file found in the source directory, the file selection conditions are checked in the
       order they are specified on the command line.  Should a selection condition match, the file will be
       included or excluded accordingly and the file selection system will proceed to the next file without
       checking the remaining conditions.

       Earlier arguments therefore take precedence where multiple conditions match any given file, and are thus
       usually given in order of decreasing specificity.  If no selection conditions match a given file, then
       the file is implicitly included.

       For example,

              duplicity --include /usr --exclude /usr /usr scp://user@host/backup

       is exactly the same as

              duplicity /usr scp://user@host/backup

       because the --include directive matches all files in the backup source directory, and takes precedence
       over the contradicting --exclude option as it comes first.

       As a more meaningful example,

              duplicity --include /usr/local/bin --exclude /usr/local /usr scp://user@host/backup

       would backup the /usr/local/bin directory (and its contents), but not /usr/local/doc. Note that this is
       not the same as simply specifying /usr/local/bin as the backup source, as other files and folders under
       /usr will also be (implicitly) included.

       The order of the --include and --exclude arguments is important. In the previous example, if the less
       specific --exclude directive had precedence it would prevent the more specific --include from matching
       any files.

       The patterns passed to the --include, --exclude, --include-filelist, and --exclude-filelist options are
       interpretted as extended shell globbing patterns by default. This behaviour can be changed with the
       following filter mode arguments:

              --filter-globbing
              --filter-literal
              --filter-regexp

       These arguments change the interpretation of the patterns used in selection conditions, affecting all
       subsequent file selection options passed on the command line. They may be specified multiple times in
       order to switch pattern interpretations as needed.

       Literal strings differ from globs in that the pattern must match the filename exactly. This can be useful
       where filenames contain characters which have special meaning in shell globs or regular expressions. If
       passing dynamically generated file lists to duplicity using the --include-filelist or --exclude-filelist
       options, then the use of --filter-literal is recommended unless regular expression or globbing is
       specifically required.

       The regular expression language used for selection conditions specified with --include-regexp ,
       --exclude-regexp , or when --filter-regexp is in effect is as implemented by the Python standard library.

       Extended shell globbing pattenrs may contain: *, **, ?, and [...]  (character ranges). As in a normal
       shell, * can be expanded to any string of characters not containing "/", ?  expands to any single
       character except "/", and [...]  expands to a single character of those characters specified (ranges are
       acceptable).  The pattern ** expands to any string of characters whether or not it contains "/".

       In addition to the above filter mode arguments, the following can be used in the same fashion to enable
       (default) or disable case sensitivity in the evaluation of file sslection conditions:

              --filter-ignorecase
              --filter-strictcase

       An example of filter mode switching including case insensitivity is

              --filter-ignorecase --include /usr/bin/*.PY --filter-literal --filter-include
              /usr/bin/special?file*name --filter-strictcase --exclude /usr/bin

       which would backup *.py, *.pY, *.Py, and *.PY files under /usr/bin and also the single literally
       specified file with globbing characters in the name. The use of --filter-strictcase is not technically
       necessary here, but is included as an example which may (depending on the backup source path) cause
       unexpected interactions between --include and --exclude options, should the directory portion of the path
       (/usr/bin) contain any uppercase characters.

       If the pattern starts with "ignorecase:" (case insensitive), then this prefix will be removed and any
       character in the string can be replaced with an upper- or lowercase version of itself. This prefix is a
       legacy feature supported for shell globbing selection conditions only, but for backward compatability
       reasons is otherwise considered part of the pattern itself (use --filter-ignorecase instead).

       Remember that you may need to quote patterns when typing them into a shell, so the shell does not
       interpret the globbing patterns or whitespace characters before duplicity sees them.

       Selection patterns should generally be thought of as filesystem paths rather than arbitrary strings. For
       selection conditions using extended shell globbing patterns, the --exclude pattern option matches a file
       if:

       1.  pattern can be expanded into the file's filename, or
       2.  the file is inside a directory matched by the option.

       Conversely, the --include pattern option matches a file if:

       1.  pattern can be expanded into the file's filename, or
       2.  the file is inside a directory matched by the option, or
       3.  the file is a directory which contains a file matched by the option.

       For example,

              --exclude /usr/local

       matches e.g. /usr/local, /usr/local/lib, and /usr/local/lib/netscape.  It is the same as --exclude
       /usr/local --exclude '/usr/local/**'.
       On the other hand

              --include /usr/local

       specifies that /usr, /usr/local, /usr/local/lib, and /usr/local/lib/netscape (but not /usr/doc) all be
       backed up. Thus you don't have to worry about including parent directories to make sure that included
       subdirectories have somewhere to go.

       Finally,

              --include ignorecase:'/usr/[a-z0-9]foo/*/**.py'

       would match a file like /usR/5fOO/hello/there/world.py.  If it did match anything, it would also match
       /usr.  If there is no existing file that the given pattern can be expanded into, the option will not
       match /usr alone.

       This treatment of patterns in globbing and literal selection conditions as filesystem paths reduces the
       number of explicit conditions required.  However, it does require that the paths described by all
       variants of the --include or --include option are fully specified relative to the backup source
       directory.

       For selection conditions using literal strings, the same logic applies except that scenario 1 is for an
       exact match of the pattern.

       For selection conditions using regular expressions the pattern is evaluated as a regular expression
       rather than a filesystem path. Scenario 3 in the above therefore does not apply, the implications of
       which are discussed at the end of this section.

       The --include-filelist, and --exclude-filelist, options also introduce file selection conditions.  They
       direct duplicity to read in a text file (either ASCII or UTF-8), each line of which is a file
       specification, and to include or exclude the matching files.  Lines are separated by newlines or nulls,
       depending on whether the --null-separator switch was given.

       Each line in the filelist will be interpreted as a selection pattern in the same way --include and
       --exclude options are interpreted, except that lines starting with "+ " are interpreted as include
       directives, even if found in a filelist referenced by --exclude-filelist.  Similarly, lines starting with
       "- " exclude files even if they are found within an include filelist.

       For example, if file "list.txt" contains the lines:

              /usr/local
              - /usr/local/doc
              /usr/local/bin
              + /var
              - /var

       then --include-filelist list.txt would include /usr, /usr/local, and /usr/local/bin.  It would exclude
       /usr/local/doc, /usr/local/doc/python, etc.  It would also include /usr/local/man, as this is included
       within /usr/local.  Finally, it is undefined what happens with /var.  A single file list should not
       contain conflicting file specifications.

       Each line in the filelist will be interpreted as per the current filter mode in the same way --include
       and --exclude options are interpreted. For instance, if the file "list.txt" contains the lines:

              dir/foo
              + dir/bar
              - **

       Then --include-filelist list.txt would be exactly the same as specifying --include dir/foo --include
       dir/bar --exclude ** on the command line.

       Note that specifying very large numbers numbers of selection rules as filelists can incur a substantial
       performance penalty as these rules will (potentially) be checked for every file in the backup source
       directory. If you need to backup arbitrary lists of specific files (i.e. not described by regexp patterns
       or shell globs) then --files-from is likely to be more performant.

       Finally, the --include-regexp and --exclude-regexp options allow files to be included and excluded if
       their filenames match a regular expression.  Regular expression syntax is too complicated to explain
       here, but is covered in Python's library reference.  Unlike the --include and --exclude options, the
       regular expression options don't match files containing or contained in matched files.  So for instance

              --include-regexp '[0-9]{7}(?!foo)'

       matches any files whose full pathnames contain 7 consecutive digits which aren't followed by 'foo'.
       However, it wouldn't match /home even if /home/ben/1234567 existed.

A NOTE ON AMAZON DRIVE

       1.     The API Keys used for Amazon Drive have not been granted production limits.  Amazon do not say
              what the development limits are and are not replying to to requests to whitelist duplicity. A
              related tool, acd_cli, was demoted to development limits, but continues to work fine except for
              cases of excessive usage. If you experience throttling and similar issues with Amazon Drive using
              this backend, please report them to the mailing list.
       2.     If you previously used the acd+acdcli backend, it is strongly recommended to update to the ad
              backend instead, since it interfaces directly with Amazon Drive. You will need to setup the OAuth
              once again, but can otherwise keep your backups and config.

A NOTE ON AMAZON S3

       Backing up to Amazon S3 utilizes the boto3 library.

       The boto3 backend does not support bucket creation.  This deliberate choice simplifies the code, and side
       steps problems related to region selection.  Additionally, it is probably not a good practice to give
       your backup role bucket creation rights.  In most cases the role used for backups should probably be
       limited to specific buckets.

       The boto3 backend only supports newer domain style buckets. Amazon is moving to deprecate the older
       bucket style, so migration is recommended.

       The boto3 backend does not currently support initiating restores from the glacier storage class.  When
       restoring a backup from glacier or glacier deep archive, the backup files must first be restored out of
       band.  There are multiple options when restoring backups from cold storage, which vary in both cost and
       speed.  See Amazon's documentation for details.

       The following environment variables are required for authentication:
              AWS_ACCESS_KEY_ID (required),
              AWS_SECRET_ACCESS_KEY (required)
              or
              BOTO_CONFIG (required) pointing to a boto config file.
       For simplicity's sake we will document the use of the AWS_* vars only.  Research boto3 documentation
       available in the web if you want to use  the config file.

       boto3 backend example backup command line:

              AWS_ACCESS_KEY_ID=<key_id> AWS_SECRET_ACCESS_KEY=<access_key> duplicity /some/path
              s3:///bucket/subfolder

       you may add --s3-endpoint-url (to access non Amazon S3 services or regional endpoints) and may need
       --s3-region-name (for buckets created in specific regions) and other --s3-...  options documented above.

A NOTE ON AZURE ACCESS

       The Azure backend requires the Microsoft Azure Storage Blobs client library for Python to be installed on
       the system.  See REQUIREMENTS.

       It uses the environment variable AZURE_CONNECTION_STRING (required).  This string contains all necessary
       information such as Storage Account name and the key for authentication.  You can find it under Access
       Keys for the storage account.

       Duplicity will take care to create the container when performing the backup.  Do not create it manually
       before.

       A container name (as given as the backup url) must be a valid DNS name, conforming to the following
       naming rules:

              1.     Container names must start with a letter or number, and can contain only letters, numbers,
                     and the dash (-) character.
              2.     Every dash (-) character must be immediately preceded and followed by a letter or number;
                     consecutive dashes are not permitted in container names.
              3.     All letters in a container name must be lowercase.
              4.     Container names must be from 3 through 63 characters long.

       These rules come from Azure; see https://docs.microsoft.com/en-us/rest/api/storageservices/naming-and-
       referencing-containers--blobs--and-metadata

A NOTE ON BOX ACCESS

       The box backend requires boxsdk with jwt support to be installed on the system.  See REQUIREMENTS.

       It uses the environment variable BOX_CONFIG_PATH (optional).  This string contains the path to box custom
       app's config.json. Either this environment variable or the config query parameter in the url need to be
       specified, if both are specified, query parameter takes precedence.

   Create a Box custom app
       In order to use box backend, user need to create a box custom app in the box developer console
       (https://app.box.com/developers/console).

       After create a new custom app, please make sure it is configured as follow:

              1.     Choose "App Access Only" for "App Access Level"
              2.     Check "Write all files and folders stored in Box"
              3.     Generate a Public/Private Keypair

       The user also need to grant the created custom app permission in the admin console
       (https://app.box.com/master/custom-apps) by clicking the "+" button and enter the client_id which can be
       found on the custom app's configuration page.

A NOTE ON CLOUD FILES ACCESS

       Pyrax is Rackspace's next-generation Cloud management API, including Cloud Files access.  The cfpyrax
       backend requires the pyrax library to be installed on the system.  See REQUIREMENTS.

       Cloudfiles is Rackspace's now deprecated implementation of OpenStack Object Storage protocol.  Users
       wishing to use Duplicity with Rackspace Cloud Files should migrate to the new Pyrax plugin to ensure
       support.

       The backend requires python-cloudfiles to be installed on the system.  See REQUIREMENTS.

       It uses three environment variables for authentication: CLOUDFILES_USERNAME (required), CLOUDFILES_APIKEY
       (required), CLOUDFILES_AUTHURL (optional)

       If CLOUDFILES_AUTHURL is unspecified it will default to the value provided by python-cloudfiles, which
       points to rackspace, hence this value must be set in order to use other cloud files providers.

A NOTE ON DROPBOX ACCESS

       1.     First of all Dropbox backend requires valid authentication token. It should be passed via
              DPBX_ACCESS_TOKEN environment variable.
              To obtain it please create 'Dropbox API' application at:
              https://www.dropbox.com/developers/apps/create
              Then visit app settings and just use 'Generated access token' under OAuth2 section.
              Alternatively you can let duplicity generate access token itself. In such case temporary export
              DPBX_APP_KEY , DPBX_APP_SECRET using values from app settings page and run duplicity
              interactively.
              It will print the URL that you need to open in the browser to obtain OAuth2 token for the
              application. Just follow on-screen instructions and then put generated token to DPBX_ACCESS_TOKEN
              variable. Once done, feel free to unset DPBX_APP_KEY and DPBX_APP_SECRET

       2.     "some_dir" must already exist in the Dropbox folder. Depending on access token kind it may be:
                     Full Dropbox: path is absolute and starts from 'Dropbox' root folder.
                     App Folder: path is related to application folder. Dropbox client will show it in
                     ~/Dropbox/Apps/<app-name>

       3.     When using Dropbox for storage, be aware that all files, including the ones in the Apps folder,
              will be synced to all connected computers.  You may prefer to use a separate Dropbox account
              specially for the backups, and not connect any computers to that account. Alternatively you can
              configure selective sync on all computers to avoid syncing of backup files

A NOTE ON FILENAME PREFIXES

       Filename prefixes can be used in multi backend with mirror mode to define affinity rules. They can also
       be used in conjunction with S3 lifecycle rules to transition archive files to Glacier, while keeping
       metadata (signature and manifest files) on S3.

       Duplicity does not require access to archive files except when restoring from backup.

A NOTE ON GOOGLE CLOUD STORAGE (GCS via Interoperable Access)

   Overview
       Duplicity access to GCS currently relies on it's Interoperability API (basically S3 for GCS).  This needs
       to actively be enabled before access is possible. For details read the next section Preparations below.

   Preparations
       1.     login on https://console.cloud.google.com/
       2.     go to Cloud Storage->Settings->Interoperability
       3.     create a Service account (if needed)
       4.     create Service account HMAC access key and secret (!!instantly copy!!  the secret, it can NOT be
              recovered later)
       5.     go to Cloud Storage->Browser
       6.     create a bucket
       7.     add permissions for Service account that was used to set up Interoperability access above

       Once set up you can use the generated Interoperable Storage Access key and secret and pass them to
       duplicity as described in the next section.

   Usage
       The following examples show accessing GCS via S3 for a collection-status action.  The shown env vars,
       options and url format can be applied for all other actions as well of course.

       using boto3 supplying the --s3-endpoint-url manually.

              AWS_ACCESS_KEY_ID=<keyid> AWS_SECRET_ACCESS_KEY=<secret> duplicity collection-status
              s3:///<bucket>/<folder> --s3-endpoint-url=https://storage.googleapis.com

A NOTE ON GDRIVE BACKEND

       GDrive: is a rewritten PyDrive: backend with less dependencies, and a simpler setup - it uses the JSON
       keys downloaded directly from Google Cloud Console.

       Note Google has 2 drive methods, `Shared(previously Team) Drives` and `My Drive`, both can be shared but
       require different addressing

       For a Google Shared Drives folder

       Share Drive ID specified as a query parameter, driveID,  in the backend URL.  Example:
             gdrive://developer.gserviceaccount.com/target-folder/?driveID=<SHARED DRIVE ID>

       For a Google My Drive based shared folder

       MyDrive folder ID specified as a query parameter, myDriveFolderID, in the backend URL Example
             export GOOGLE_SERVICE_ACCOUNT_URL=<serviceaccount-name>@<serviceaccount-
       name>.iam.gserviceaccount.com
             gdrive://${GOOGLE_SERVICE_ACCOUNT_URL}/<target-folder-name-in-myDriveFolder>?myDriveFolderID=root

       There are also two ways to authenticate to use GDrive: with a regular account or with a "service
       account". With a service account, a separate account is created, that is only accessible with Google APIs
       and not a web login.  With a regular account, you can store backups in your normal Google Drive.

       To use a service account, go to the Google developers console at https://console.developers.google.com.
       Create a project, and make sure Drive API is enabled for the project. In the "Credentials" section, click
       "Create credentials", then select Service Account with JSON key.

       The GOOGLE_SERVICE_JSON_FILE environment variable needs to contain the path to the JSON file on duplicity
       invocation.

       export GOOGLE_SERVICE_JSON_FILE=<path-to-serviceaccount-credentials.json>

       The alternative is to use a regular account. To do this, start as above, but when creating a new Client
       ID, select "Create OAuth client ID", with application type of "Desktop app". Download the
       client_secret.json file for the new client, and set the GOOGLE_CLIENT_SECRET_JSON_FILE environment
       variable to the path to this file, and GOOGLE_CREDENTIALS_FILE to a path to a file where duplicity will
       keep the authentication token - this location must be writable.

       NOTE: As a sanity check, GDrive checks the host and username from the URL against the JSON key, and
       refuses to proceed if the addresses do not match. Either the email (for the service accounts) or Client
       ID (for regular OAuth accounts) must be present in the URL. See URL FORMAT above.

   First run / OAuth 2.0 authorization
       During the first run, you will be prompted to visit an URL in your browser to grant access to your Google
       Drive. A temporary HTTP-service will be started on a local network interface for this purpose (by default
       on http://localhost:8080/).  Ip-address/host and port can be adjusted if need be by providing the
       environment variables GOOGLE_OAUTH_LOCAL_SERVER_HOST, GOOGLE_OAUTH_LOCAL_SERVER_PORT respectively.

       If you are running duplicity in a remote location, you will need to make sure that you will be able to
       access the above HTTP-service with a browser utilizing e.g. port forwarding or temporary firewall
       permission.

       The access credentials will be saved in the JSON file mentioned above for future use after a successful
       authorization.

A NOTE ON HUBIC

       The hubic backend requires the pyrax library to be installed on the system. See REQUIREMENTS.  You will
       need to set your credentials for hubiC in a file called ~/.hubic_credentials, following this pattern:
              [hubic]
              email = your_email
              password = your_password
              client_id = api_client_id
              client_secret = api_secret_key
              redirect_uri = http://localhost/

A NOTE ON IMAP

       An IMAP account can be used as a target for the upload.  The userid may be specified and the password
       will be requested.
       The from_address_prefix may be specified (and probably should be). The text will be used as the "From"
       address in the IMAP server.  Then on a restore (or list) action the from_address_prefix will distinguish
       between different backups.

A NOTE ON MEDIAFIRE BACKEND

       This backend requires mediafire python library to be installed on the system. See REQUIREMENTS.

       Use URL escaping for username (and password, if provided via command line):

              mf://duplicity%40example.com@mediafire.com/some_folder
       The destination folder will be created for you if it does not exist.

A NOTE ON MULTI BACKEND

       The multi backend allows duplicity to combine the storage available in more than one backend store (e.g.,
       you can store across a google drive account and a onedrive account to get effectively the combined
       storage available in both).  The URL path specifies a JSON formatted config file containing a list of the
       backends it will use. The URL may also specify "query" parameters to configure overall behavior.  Each
       element of the list must have a "url" element, and may also contain an optional "description" and an
       optional "env" list of environment variables used to configure that backend.
   Query Parameters
       Query parameters come after the file URL in standard HTTP format for example:
              multi:///path/to/config.json?mode=mirror&onfail=abort
              multi:///path/to/config.json?mode=stripe&onfail=continue
              multi:///path/to/config.json?onfail=abort&mode=stripe
              multi:///path/to/config.json?onfail=abort
       Order does not matter, however unrecognized parameters are considered an error.

       mode=stripe
              This mode (the default) performs round-robin access to the list of backends. In this mode, all
              backends must be reliable as a loss of one means a loss of one of the archive files.

       mode=mirror
              This mode accesses backends as a RAID1-store, storing every file in every backend and reading
              files from the first-successful backend.  A loss of any backend should result in no failure. Note
              that backends added later will only get new files and may require a manual sync with one of the
              other operating ones.

       onfail=continue
              This setting (the default) continues all write operations in as best-effort. Any failure results
              in the next backend tried. Failure is reported only when all backends fail a given operation with
              the error result from the last failure.

       onfail=abort
              This setting considers any backend write failure as a terminating condition and reports the error.
              Data reading and listing operations are independent of this and will try with the next backend on
              failure.
   JSON File Example
              [
               {
                "description": "a comment about the backend"
                "url": "abackend://myuser@domain.com/backup",
                "env": [
                  {
                   "name" : "MYENV",
                   "value" : "xyz"
                  },
                  {
                   "name" : "FOO",
                   "value" : "bar"
                  }
                 ],
                 "prefixes": ["prefix1_", "prefix2_"]
               },
               {
                "url": "file:///path/to/dir"
               }
              ]

A NOTE ON ONEDRIVE BACKEND

       onedrive:// works with both personal and business onedrive as well as sharepoint drives.  On first use
       you be provided with an URL to with a microsoft account. Open it in your web browser.

       After authenticating, copy the redirected URL back to duplicity. Duplicity will fetch a token and store
       it in ~/.duplicity_onedrive_oauthtoken.json. This location can be overridden by setting the
       DUPLICITY_ONEDRIVE_TOKEN environment variable.

       Duplicity uses a default App ID registered with Microsoft Azure AD.  It will need to be approved by an
       administrator of your Office365 Tenant on a business account.

   Register and set your own microsoft app id
       1.     visit https://portal.azure.com

       2.     Choose "Enterprise Applications", then "Create your own Application"

       3.     Input your application name and select "Register an application to integrate with Azure AD".

       4.     Continue to the next page and set the redirect uri to
              "https://login.microsoftonline.com/common/oauth2/nativeclient", choosing "Public client/native"
              from the dropdown. Click create.

       5.     Find the application id in "Enterprise Applications" and set the environment variable
              DUPLICITY_ONEDRIVE_CLIENT_ID to it.

               More information on Microsoft Apps at: https://learn.microsoft.com/en-us/azure/active-
              directory/develop/quickstart-register-app

   Backup to a sharepoint site instead of onedrive
       to use a sharepoint site you need to find and provide the site's tenant and site id.

       1.     Login with your Microsoft Account at https://<o365_tenant>.sharepoint.com/

       2.     Navigate to https://<o365_tenant>.sharepoint.com/sites/<path_to_site>/_api/site/id

       3.     Copy the disyplayed UUID (site_id) and set the DUPLICITY_ONEDRIVE_ROOT environment variable to
              "sites/<o365_tenant>.sharepoint.com,<site_id>/drive"

A NOTE ON PAR2 WRAPPER BACKEND

       Par2 Wrapper Backend can be used in combination with all other backends to create recovery files. Just
       add par2+ before a regular scheme (e.g.  par2+ftp://user@host/dir or par2+s3+http://bucket_name ). This
       will create par2 recovery files for each archive and upload them all to the wrapped backend.
       Before restoring, archives will be verified. Corrupt archives will be repaired on the fly if there are
       enough recovery blocks available.
       Use --par2-redundancy percent to adjust the size (and redundancy) of recovery files in percent.

A NOTE ON PCA ACCESS

       PCA is a long-term data archival solution by OVH. It runs a slightly modified version of Openstack Swift
       introducing latency in the data retrieval process.  It is a good pick for a multi backend configuration
       where receiving volumes while another backend is used to store manifests and signatures.

       The backend requires python-switclient to be installed on the system.  python-keystoneclient is also
       needed to interact with OpenStack's Keystone Identity service.  See REQUIREMENTS.

       It uses following environment variables for authentication: PCA_USERNAME (required), PCA_PASSWORD
       (required), PCA_AUTHURL (required), PCA_USERID (optional), PCA_TENANTID (optional, but either the tenant
       name or tenant id must be supplied) PCA_REGIONNAME (optional), PCA_TENANTNAME (optional, but either the
       tenant name or tenant id must be supplied)

       If the user was previously authenticated, the following environment variables can be used instead:
       PCA_PREAUTHURL (required), PCA_PREAUTHTOKEN (required)

       If PCA_AUTHVERSION is unspecified, it will default to version 2.

A NOTE ON PYDRIVE BACKEND

       The pydrive backend requires Python PyDrive package to be installed on the system. See REQUIREMENTS.

       There are two ways to use PyDrive: with a regular account or with a "service account". With a service
       account, a separate account is created, that is only accessible with Google APIs and not a web login.
       With a regular account, you can store backups in your normal Google Drive.

       To use a service account, go to the Google developers console at https://console.developers.google.com.
       Create a project, and make sure Drive API is enabled for the project. Under "APIs and auth", click Create
       New Client ID, then select Service Account with P12 key.

       Download the .p12 key file of the account and convert it to the .pem format:
       openssl pkcs12 -in XXX.p12  -nodes -nocerts > pydriveprivatekey.pem

       The content of .pem file should be passed to GOOGLE_DRIVE_ACCOUNT_KEY environment variable for
       authentication.

       The email address of the account will be used as part of URL. See URL FORMAT above.

       The alternative is to use a regular account. To do this, start as above, but when creating a new Client
       ID, select "Installed application" of type "Other". Create a file with the following content, and pass
       its filename in the GOOGLE_DRIVE_SETTINGS environment variable:
              client_config_backend: settings
              client_config:
                  client_id: <Client ID from developers' console>
                  client_secret: <Client secret from developers' console>
              save_credentials: True
              save_credentials_backend: file
              save_credentials_file: <filename to cache credentials>
              get_refresh_token: True

       In this scenario, the username and host parts of the URL play no role; only the path matters. During the
       first run, you will be prompted to visit an URL in your browser to grant access to your drive. Once
       granted, you will receive a verification code to paste back into Duplicity. The credentials are then
       cached in the file references above for future use.

A NOTE ON RCLONE BACKEND

       Rclone is a powerful command line program to sync files and directories to and from various cloud storage
       providers.

   Usage
       Once you have configured an rclone remote via

              rclone config

       and successfully set up a remote (e.g. gdrive for Google Drive), assuming you can list your remote files
       with

              rclone ls gdrive:mydocuments

       you can start your backup with

              duplicity /mydocuments rclone://gdrive:/mydocuments

       Please note the slash after the second colon. Some storage provider will work with or without slash after
       colon, but some other will not. Since duplicity will complain about malformed URL if a slash is not
       present, always put it after the colon, and the backend will handle it for you.

   Options
       Note that all rclone options can be set by env vars as well. This is properly documented here

              https://rclone.org/docs/

       but in a nutshell you need to take the long option name, strip the leading --, change - to _, make upper
       case and prepend RCLONE_. for example

              the equivalent of '--stats 5s' would be the env var RCLONE_STATS=5s

A NOTE ON SLATE BACKEND

       Three environment variables are used with the slate backend:
         1.  `SLATE_API_KEY` - Your slate API key
         2.  `SLATE_SSL_VERIFY` - either '1'(True) or '0'(False) for ssl verification (optional - True by
       default)
         3.  `PASSPHRASE` - your gpg passhprase for encryption (optional - will be prompted if not set or not
       used at all if using the `--no-encryption` parameter)

       To use the slate backend, use the following scheme:
              slate://[slate-id]

       e.g. Full backup of current directory to slate:
              duplicity full . "slate://6920df43-5c3w-2x7i-69aw-2390567uav75"

       Here's a demo:
       https://gitlab.com/Shr1ftyy/duplicity/uploads/675664ef0eb431d14c8e20045e3fafb6/slate_demo.mp4

A NOTE ON SSH BACKENDS

       The ssh backends support sftp and scp/ssh transport protocols.  This is a known user-confusing issue as
       these are fundamentally different.  If you plan to access your backend via one of those please inform
       yourself about the requirements for a server to support sftp or scp/ssh access.  To make it even more
       confusing the user can choose between several ssh backends via a scheme prefix: paramiko+ (default),
       pexpect+, lftp+... .
       paramiko & pexpect support --use-scp, --ssh-askpass and --ssh-options.  Only the pexpect backend allows
       one to define --scp-command and --sftp-command.
       SSH paramiko backend (default) is a complete reimplementation of ssh protocols natively in python.
       Advantages are speed and maintainability. Minor disadvantage is that extra packages are needed as listed
       in REQUIREMENTS.  In sftp (default) mode all operations are done via the according sftp commands. In scp
       mode ( --use-scp ) though scp access is used for put/get operations but listing is done via ssh remote
       shell.
       SSH pexpect backend is the legacy ssh backend using the command line ssh binaries via pexpect.  Older
       versions used scp for get and put operations and sftp for list and delete operations.  The current
       version uses sftp for all four supported operations, unless the --use-scp option is used to revert to old
       behavior.
       SSH lftp backend is simply there because lftp can interact with the ssh cmd line binaries.  It is meant
       as a last resort in case the above options fail for some reason.

   Why use sftp instead of scp?
       The change to sftp was made in order to allow the remote system to chroot the backup, thus providing
       better security and because it does not suffer from shell quoting issues like scp.  Scp also does not
       support any kind of file listing, so sftp or ssh access will always be needed in addition for this
       backend mode to work properly. Sftp does not have these limitations but needs an sftp service running on
       the backend server, which is sometimes not an option.

A NOTE ON SSL CERTIFICATE VERIFICATION

       Certificate verification as implemented right now [02.2016] only in the webdav and lftp backends. older
       pythons 2.7.8- and older lftp binaries need a file based database of certification authority certificates
       (cacert file).
       Newer python 2.7.9+ and recent lftp versions however support the system default certificates (usually in
       /etc/ssl/certs) and also giving an alternative ca cert folder via --ssl-cacert-path.
       The cacert file has to be a PEM formatted text file as currently provided by the CURL project. See
              http://curl.haxx.se/docs/caextract.html
       After creating/retrieving a valid cacert file you should copy it to either
              ~/.duplicity/cacert.pem
              ~/duplicity_cacert.pem
              /etc/duplicity/cacert.pem
       Duplicity searches it there in the same order and will fail if it can't find it.  You can however specify
       the option --ssl-cacert-file <file> to point duplicity to a copy in a different location.
       Finally there is the --ssl-no-check-certificate option to disable certificate verification altogether, in
       case some ssl library is missing or verification is not wanted. Use it with care, as even with self
       signed servers manually providing the private ca certificate is definitely the safer option.

A NOTE ON SWIFT (OPENSTACK OBJECT STORAGE) ACCESS

       Swift is the OpenStack Object Storage service.
       The backend requires python-switclient to be installed on the system.  python-keystoneclient is also
       needed to use OpenStack's Keystone Identity service.  See REQUIREMENTS.

       It uses following environment variables for authentication:

              SWIFT_USERNAME (required),
              SWIFT_PASSWORD (required),
              SWIFT_AUTHURL (required),
              SWIFT_TENANTID or SWIFT_TENANTNAME (required with SWIFT_AUTHVERSION=2, can alternatively be
              defined in SWIFT_USERNAME like e.g. SWIFT_USERNAME="tenantname:user"),
              SWIFT_PROJECT_ID or SWIFT_PROJECT_NAME (required with SWIFT_AUTHVERSION=3),
              SWIFT_USERID (optional, required only for IBM Bluemix ObjectStorage),
              SWIFT_REGIONNAME (optional).

       If the user was previously authenticated, the following environment variables can be used instead:
       SWIFT_PREAUTHURL (required), SWIFT_PREAUTHTOKEN (required)

       If SWIFT_AUTHVERSION is unspecified, it will default to version 1.

A NOTE ON SYMMETRIC ENCRYPTION AND SIGNING

       Signing and symmetrically encrypt at the same time with the gpg binary on the command line, as used
       within duplicity, is a specifically challenging issue.  Tests showed that the following combinations
       proved working.
       1. Setup gpg-agent properly. Use the option --use-agent and enter both passphrases (symmetric and sign
       key) in the gpg-agent's dialog.
       2. Use a PASSPHRASE for symmetric encryption of your choice but the signing key has an empty passphrase.
       3. The used PASSPHRASE for symmetric encryption and the passphrase of the signing key are identical.

A NOTE ON THE XORRISO BACKEND

       This backend uses the xorriso tool to append backups to optical media or ISO9660 images.

       Use the following environment variables for more settings:
              XORRISO_PATH, set an alternative path to the xorriso executable
              XORRISO_WRITE_SPEED, specify the speed for writing to the optical disc. One of [min, max]
              XORRISO_ASSERT_VOLID, specify the required volume ID of the ISO. Aborts when the actual volume ID
              is different.
              XORRISO_ARGS, for expert use only. Pass arbitrary arguments to xorriso. Example:
              XORRISO_ARGS='-md5 all'

KNOWN ISSUES / BUGS

       Hard links currently unsupported (they will be treated as non-linked regular files).

       Bad signatures will be treated as empty instead of logging appropriate error message.

OPERATION AND DATA FORMATS

       This section describes duplicity's basic operation and the format of its data files.  It should not be
       necessary to read this section to use duplicity.

       The files used by duplicity to store backup data are tarfiles in GNU tar format.  For incremental
       backups, new files are saved normally in the tarfile.  But when a file changes, instead of storing a
       complete copy of the file, only a diff is stored, as generated by rdiff(1).  If a file is deleted, a 0
       length file is stored in the tar.  It is possible to restore a duplicity archive "manually" by using tar
       and then cp, rdiff, and rm as necessary.  These duplicity archives have the extension difftar.

       Both full and incremental backup sets have the same format.  In effect, a full backup set is an
       incremental one generated from an empty signature (see below).  The files in full backup sets will start
       with duplicity-full while the incremental sets start with duplicity-inc.  When restoring, duplicity
       applies patches in order, so deleting, for instance, a full backup set may make related incremental
       backup sets unusable.

       In order to determine which files have been deleted, and to calculate diffs for changed files, duplicity
       needs to process information about previous sessions.  It stores this information in the form of tarfiles
       where each entry's data contains the signature (as produced by rdiff) of the file instead of the file's
       contents.  These signature sets have the extension sigtar.

       Signature files are not required to restore a backup set, but without an up-to-date signature, duplicity
       cannot append an incremental backup to an existing archive.

       To save bandwidth, duplicity generates full signature sets and incremental signature sets.  A full
       signature set is generated for each full backup, and an incremental one for each incremental backup.
       These start with duplicity-full-signatures and duplicity-new-signatures respectively. These signatures
       will be stored both locally and remotely.  The remote signatures will be encrypted if encryption is
       enabled.  The local signatures will not be encrypted and stored in the archive dir (see --archive-dir ).

REQUIREMENTS

       Duplicity requires a POSIX-like operating system with a python interpreter version 3.8+ installed.  It is
       best used under GNU/Linux.

       Some backends also require additional components (probably available as packages for your specific
       platform):

       Amazon Drive backend
              python-requests - http://python-requests.org
              python-requests-oauthlib - https://github.com/requests/requests-oauthlib

       azure backend (Azure Storage Blob Service)
              Microsoft Azure Storage Blobs client library for Python - https://pypi.org/project/azure-storage-
              blob/

       boto3 backend (S3 Amazon Web Services, Google Cloud Storage) (default)
              boto3 version 1.x - https://github.com/boto/boto3

       box backend (box.com)
              boxsdk - https://github.com/box/box-python-sdk

       cfpyrax backend (Rackspace Cloud) and hubic backend (hubic.com)
              Rackspace CloudFiles Pyrax API - http://docs.rackspace.com/sdks/guide/content/python.html

       dpbx backend (Dropbox)
              Dropbox Python SDK - https://www.dropbox.com/developers/reference/sdk

       gdocs gdata backend (legacy)
              Google Data APIs Python Client Library - http://code.google.com/p/gdata-python-client/

       gdocs pydrive backend(default)
              see pydrive backend

       gio backend (Gnome VFS API)
              PyGObject - http://live.gnome.org/PyGObject
              D-Bus (dbus)- http://www.freedesktop.org/wiki/Software/dbus

       lftp backend (needed for ftp, ftps, fish [over ssh] - also supports sftp, webdav[s])
              LFTP Client - http://lftp.yar.ru/

       MEGA backend (only works for accounts created prior to November 2018) (mega.nz)
              megatools client - https://github.com/megous/megatools

       MEGA v2 and v3 backend (works for all MEGA accounts) (mega.nz)
              MEGAcmd client - https://mega.nz/cmd

       multi backend
              Multi -- store to more than one backend
              (also see A NOTE ON MULTI BACKEND ) below.

       ncftp backend (ftp, select via ncftp+ftp://)
              NcFTP - http://www.ncftp.com/

       OneDrive backend (Microsoft OneDrive)
              python-requests-oauthlib - https://github.com/requests/requests-oauthlib

       Par2 Wrapper Backend
              par2cmdline - http://parchive.sourceforge.net/

       pydrive backend
              PyDrive -- a wrapper library of google-api-python-client - https://pypi.python.org/pypi/PyDrive
              (also see A NOTE ON PYDRIVE BACKEND ) below.

       rclone backend
              rclone - https://rclone.org/

       rsync backend
              rsync client binary - http://rsync.samba.org/

       ssh paramiko backend (default)
              paramiko (SSH2 for python) - http://pypi.python.org/pypi/paramiko (downloads);
              http://github.com/paramiko/paramiko (project page)
              pycrypto (Python Cryptography Toolkit) - http://www.dlitz.net/software/pycrypto/

       ssh pexpect backend(legacy)
              sftp/scp client binaries OpenSSH - http://www.openssh.com/
              Python pexpect module - http://pexpect.sourceforge.net/pexpect.html

       swift backend (OpenStack Object Storage)
              Python swiftclient module - https://github.com/openstack/python-swiftclient/
              Python keystoneclient module - https://github.com/openstack/python-keystoneclient/

       webdav backend
              certificate authority database file for ssl certificate verification of HTTPS connections -
              http://curl.haxx.se/docs/caextract.html
              (also see A NOTE ON SSL CERTIFICATE VERIFICATION).
              Python kerberos module for kerberos authentication - https://github.com/02strich/pykerberos

       MediaFire backend
              MediaFire Python Open SDK - https://pypi.python.org/pypi/mediafire/

       xorriso backend
              xorriso - https://www.gnu.org/software/xorriso/

AUTHOR

       Original Author - Ben Escoto <bescoto@stanford.edu>

       Current Maintainer - Kenneth Loafman <kenneth@loafman.com>

       Continuous Contributors
              Edgar Soldin, Mike Terry
       Most backends were contributed individually.  Information about their authorship may be found in the
       according file's header.
       Also we'd like to thank everybody posting issues to the mailing list or on launchpad, sending in patches
       or contributing otherwise. Duplicity wouldn't be as stable and useful if it weren't for you.
       A special thanks goes to rsync.net, a Cloud Storage provider with explicit support for duplicity, for
       several monetary donations and for providing a special "duplicity friends" rate for their offsite backup
       service.  Email info@rsync.net for details.

SEE ALSO

       python(1), rdiff(1), rdiff-backup(1).