Provided by: duplicity_0.7.18.2-1ubuntu3.1_amd64 bug

NAME

       duplicity - Encrypted incremental backup to local or remote storage.

SYNOPSIS

       For detailed descriptions for each command see chapter ACTIONS.

       duplicity [full|incremental] [options] source_directory target_url

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

       duplicity collection-status [options] target_url

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

       duplicity [restore] [options] [--file-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] [--extra-clean] 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 --file-to-restore Mail/article sftp://uid@other.host/some_dir
              /home/me/restored_file

       The following command 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 knows action commands, which can be finetuned with options.
       The actions for backup (full,incr) and restoration (restore) can as well be left out as
       duplicity detects in what mode it should switch to by the order of target URL and local
       folder. If the target URL comes before the local folder a restore is in order, is the
       local folder before target URL then this folder is about to be backed up to the target
       URL.
       If a backup is in order and old signatures can be found duplicity automatically performs
       an incremental backup.

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

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

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

       verify [--compare-data] [--time <time>] [--file-to-restore <rel_path>] <url> <local_path>
              Restore backup contents temporarily file by file and compare against the local
              path's contents.  duplicity will exit with a non-zero error level if any files are
              different.  On verbosity level info (4) or higher, a message for each file that has
              changed will be logged.
              The --file-to-restore option restricts verify to that file or folder.  The --time
              option allows to select a backup to verify against.  The --compare-data option
              enables data comparison (see below).

       collection-status <url>
              Summarize the status of the backup repository by printing the chains and sets
              found, and the number of volumes in each.

       list-current-files [--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 command will not detect it.

       restore [--file-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 <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 <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 <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 [--force] [--extra-clean] <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.

       --backend-retry-delay number
              Specifies the number of seconds that duplicity waits after an error has occured
              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.

       --compare-data
              Enable data comparison of regular files on action verify.  This is disabled by
              default for performance reasons.

       --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 rdiff-backup 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. This option needs to come before
              any other include or exclude options.

       --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.

       --extra-clean
              When cleaning up, be more aggressive about saving space.  For example, this may
              delete signature files for old backup chains.

              Caution: Without signature files those old backup chains are unrestorable. Do not
              use --extra-clean unless you know what you're doing.

              See the cleanup argument for more information.

       --file-prefix, --file-prefix-manifest, --file-prefix-archive, --file-prefix-signature
              Adds a prefix to all files, manifest files, archive files, and/or 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

       --file-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.

       --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.

       --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.

       --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.

       --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.

       --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.

       --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, globals.max_blocksize)

              where globals.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.

       --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-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.

       --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 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.

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

       --old-filenames
              Use the old filename format (incompatible with Windows/Samba) rather than the new
              filename format.

       --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%).

       --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 prompt 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-european-buckets
              When using the Amazon S3 backend, create buckets in Europe instead of the default
              (requires --s3-use-new-style ). Also see the EUROPEAN S3 BUCKETS section.

       --s3-unencrypted-connection
              Don't use SSL for connections to S3.

              This may be much faster, at some cost to confidentiality.

              With this option, anyone who can observe traffic between your computer and S3 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.

       --s3-use-new-style
              When operating on Amazon S3 buckets, use new-style subdomain bucket addressing.
              This is now the preferred method to access Amazon S3, but is not backwards
              compatible if your bucket name contains upper-case characters or other characters
              that are not valid in a hostname.

       --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-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-multiprocessing
              Allow multipart volumne uploads to S3 through multiprocessing. This option requires
              Python 2.6 and can be used to make uploads to S3 more efficient.  If enabled, files
              duplicity uploads to S3 will be split into chunks and uploaded in parallel. Useful
              if you want to saturate your bandwidth or if large files are failing during upload.

       --s3-use-server-side-encryption
              Allow use of server side encryption in S3

       --s3-multipart-chunk-size
              Chunk size (in MB) used for S3 multipart uploads. Make this smaller than --volsize
              to maximize the use of your bandwidth. For example, a chunk size of 10MB with a
              volsize of 30MB will result in 3 chunks per volume upload.

       --s3-multipart-max-procs
              Specify the maximum number of processes to spawn when performing a multipart upload
              to S3. By default, this will choose the number of processors detected on your
              system (e.g. 4 for a 4-core system). You can adjust this number as required to
              ensure you don't overload your system while maximizing the use of your bandwidth.

       --s3-multipart-max-timeout
              You can control the maximum time (in seconds) a multipart upload can spend on
              uploading a single chunk to S3. This may be useful if you find your system hanging
              on multipart uploads or if you'd like to control the time variance when uploading
              to S3 to ensure you kill connections to slow S3 endpoints.

       --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.

       --short-filenames
              If this option is specified, the names of the files duplicity writes will be
              shorter (about 30 chars) but less understandable.  This may be useful when backing
              up to MacOS or another OS or FS that doesn't support long filenames.

       --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
              setting. 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.

       --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.

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

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

       --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.

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
              supercedes 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.

       SIGN_PASSPHRASE
              The passphrase to be used for --sign-key.  If ommitted 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.

URL FORMAT

       Duplicity uses the URL format (as standard as possible) to define data locations.  The
       generic format for a URL is:

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

       Azure

              azure://container-name

              See also A NOTE ON AZURE ACCESS

       B2

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

       Cloud Files (Rackspace)

              cf+http://container_name

              See also A NOTE ON CLOUD FILES ACCESS

       Copy cloud storage

              copy://user[:password]@copy.com/some_dir

       Dropbox

              dpbx:///some_dir

              Make sure to read A NOTE ON DROPBOX ACCESS first!

       Local file path

              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 Docs

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

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

       Google Cloud Storage

              gs://bucket[/prefix]

       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

       Mega cloud storage

              mega://user[:password]@mega.co.nz/some_dir

       OneDrive Backend

              onedrive://some_dir

       Par2 Wrapper Backend

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

              See also A NOTE ON PAR2 WRAPPER 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://host[:port]/bucket_name[/prefix]
              s3+http://bucket_name[/prefix]

              See also A NOTE ON EUROPEAN S3 BUCKETS

       SCP/SFTP access

              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.

       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]://

       pydrive

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

              See also A NOTE ON PYDRIVE BACKEND below.

       multi

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

              See also A NOTE ON MULTI BACKEND below.

       MediaFire

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

              See also A NOTE ON MEDIAFIRE BACKEND below.

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.  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-filelist
              --exclude-regexp
              --include
              --include-filelist
              --include-regexp
       Each file selection condition either matches or doesn't match a given file.  A given file
       is excluded by the file selection system exactly when the first matching file selection
       condition specifies that the file be excluded; otherwise the file is included.

       For instance,

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

       is exactly the same as

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

       because the include and exclude directives match exactly the same files, and the --include
       comes first, giving it precedence.  Similarly,

              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.

       The include, exclude, include-filelist, and exclude-filelist options accept some extended
       shell globbing patterns.  These patterns can contain *, **, ?, and [...]  (character
       ranges). As in a normal shell, * can be expanded to any string of characters not
       containing "/", ?  expands to any character except "/", and [...]  expands to a single
       character of those characters specified (ranges are acceptable).  The new special pattern,
       **, expands to any string of characters whether or not it contains "/".  Furthermore, 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.

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

       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 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.

       The --include-filelist, and --exclude-filelist, options also introduce file selection
       conditions.  They direct duplicity to read in a file, 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 globbing pattern the 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 /user/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 also be interpreted as a globbing pattern the 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.

       Finally, the --include-regexp and --exclude-regexp options allow files to be included and
       excluded if their filenames match a python 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 '[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 AZURE ACCESS

       The Azure backend requires the Microsoft Azure Storage SDK for Python to be installed on
       the system.  See REQUIREMENTS above.

       It uses two environment variables for authentification: AZURE_ACCOUNT_NAME (required),
       AZURE_ACCOUNT_KEY (required)

       A container name 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.

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 above.

       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
       above.

       It uses three environment variables for authentification: 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 EUROPEAN S3 BUCKETS

       Amazon S3 provides the ability to choose the location of a bucket upon its creation. The
       purpose is to enable the user to choose a location which is better located network
       topologically relative to the user, because it may allow for faster data transfers.

       duplicity will create a new bucket the first time a bucket access is attempted. At this
       point, the bucket will be created in Europe if --s3-european-buckets was given. For
       reasons having to do with how the Amazon S3 service works, this also requires the use of
       the --s3-use-new-style option. This option turns on subdomain based bucket addressing in
       S3. The details are beyond the scope of this man page, but it is important to know that
       your bucket must not contain upper case letters or any other characters that are not valid
       parts of a hostname. Consequently, for reasons of backwards compatibility, use of
       subdomain based bucket addressing is not enabled by default.

       Note that you will need to use --s3-use-new-style for all operations on European buckets;
       not just upon initial creation.

       You only need to use --s3-european-buckets upon initial creation, but you may may use it
       at all times for consistency.

       Further note that when creating a new European bucket, it can take a while before the
       bucket is fully accessible. At the time of this writing it is unclear to what extent this
       is an expected feature of Amazon S3, but in practice you may experience timeouts, socket
       errors or HTTP errors when trying to upload files to your newly created bucket. Give it a
       few minutes and the bucket should function normally.

A NOTE ON FILENAME PREFIXES

       Filename prefixes can 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

       Support for Google Cloud Storage relies on its Interoperable Access, which must be enabled
       for your account.  Once enabled, you can generate Interoperable Storage Access Keys and
       pass them to duplicity via the GS_ACCESS_KEY_ID and GS_SECRET_ACCESS_KEY environment
       variables. Alternatively, you can run gsutil config -a to have the Google Cloud Storage
       utility populate the ~/.boto configuration file.

       Enable Interoperable Access: https://code.google.com/apis/console#:storage
       Create Access Keys: https://code.google.com/apis/console#:storage:legacy

A NOTE ON HUBIC

       The hubic backend requires the pyrax library to be installed on the system. See
       REQUIREMENTS above.  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) command the
       from_address_prefix will distinguish between different backups.

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
       formated 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"
                  }
                 ]
               },
               {
                "url": "file:///path/to/dir"
               }
              ]

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 PYDRIVE BACKEND

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

       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 authentification.

       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 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 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 above. 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
       alltogether, 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 above.

       It uses following environment variables for authentification: SWIFT_USERNAME (required),
       SWIFT_PASSWORD (required), SWIFT_AUTHURL (required), SWIFT_USERID (required, only for IBM
       Bluemix ObjectStorage), SWIFT_TENANTID (required, only for IBM Bluemix ObjectStorage),
       SWIFT_REGIONNAME (required, only for IBM Bluemix ObjectStorage), SWIFT_TENANTNAME
       (optional, the tenant can be included in the username)

       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 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 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.

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.  They can
       be produced independently by rdiffdir(1).  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 2.6+
       installed.  It is best used under GNU/Linux.

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

       azure backend (Azure Blob Storage Service)
              Microsoft Azure Storage SDK for Python - https://pypi.python.org/pypi/azure-
              storage/

       boto backend (S3 Amazon Web Services, Google Cloud Storage)
              boto version 2.0+ - http://github.com/boto/boto

       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

       copy backend (Copy.com)
              python-urllib3 - https://github.com/shazow/urllib3

       gdocs gdata backend (legacy Google Docs backend)
              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 (mega.co.nz)
              megatools client - https://github.com/megous/megatools

       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 - http://python-requests.org
              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.

       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
              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/

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

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