Provided by: duplicity_0.6.23-1ubuntu4.1_amd64 
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
REQUIREMENTS
Duplicity requires a POSIX-like operating system with a python interpreter version 2.4+ installed. It is
best used under GNU/Linux.
Some backends also require additional components (probably available as packages for your specific
platform):
boto backend (S3 Amazon Web Services, Google Cloud Storage)
boto version 2.0+ - http://github.com/boto/boto
cloudfiles backend (deprecated) (e.g. Rackspace Open Cloud)
Cloud Files Python API (deprecated) - http://www.rackspace.com/knowledge_center/article/python-
api-installation-for-cloud-files
cfpyrax backend (Rackspace Cloud)
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
ftp backend
NcFTP Client - http://www.ncftp.com/
ftps backend
LFTP Client - http://lftp.yar.ru/
gdocs backend (Google Docs)
Google Data APIs Python Client Library - http://code.google.com/p/gdata-python-client/
gio backend (Gnome VFS API)
PyGObject - http://live.gnome.org/PyGObject
D-Bus (dbus)- http://www.freedesktop.org/wiki/Software/dbus
rsync backend
rsync client binary - http://rsync.samba.org/
mega backend (mega.co.nz)
Python library for mega API - https://github.com/ckornacker/mega.py, ubuntu ppa -
ppa:ckornacker/backup
There are two ssh backends for scp/sftp/ssh access (also see A NOTE ON SSH BACKENDS).
ssh paramiko backend (enabled by 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/
swift backend (OpenStack Object Storage)
Python swiftclient module - https://github.com/openstack/python-swiftclient/
Python keystoneclient module - https://github.com/openstack/python-keystoneclient/
Ubuntu One
httplib2 (python HTTP client library) - http://code.google.com/p/httplib2/
oauthlib (python OAuth request-signing logic) - http://pypi.python.org/pypi/oauthlib
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).
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 <relpath>] <url> <folder>
Verify compares the backup contents with the source folder. 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.
--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.
--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. See the FILE SELECTION section for more information.
--exclude-filelist-stdin
Like --exclude-filelist, but the list of files will be read from standard input. See the FILE
SELECTION section for more information.
--exclude-globbing-filelist filename
Like --exclude-filelist but each line of the filelist will be interpreted according to the same
rules as --include and --exclude.
--exclude-if-present filename
Exclude directories if filename is present. This option needs to come before any other include or
exclude options.
--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-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-mailbox option
Allows you to specify a different mailbox. The default is "INBOX". Other languages may require a
different mailbox than the default.
--gpg-options options
Allows you to pass options to gpg encryption. The options list should be of the form "opt1=parm1
opt2=parm2" 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-filelist-stdin
Like --include-filelist, but read the list of included files from standard input.
--include-globbing-filelist filename
Like --include-filelist but each line of the filelist will be interpreted according to the same
rules as --include and --exclude.
--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.
--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-encryption
Do not use GnuPG to encrypt files on remote system. Instead just write gzipped volumes.
--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[-stdin] 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.
--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.
--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 givein 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-backend backend
Allows the explicit selection of a ssh backend. Defaults to paramiko. Alternatively you might
choose pexpect.
See also A NOTE ON SSH BACKENDS.
--ssh-options options
Allows you to pass options to the ssh backend. 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), like in this example:
duplicity --ssh-options="-oProtocol=2 -oIdentityFile=/my/backup/id" /home/me
scp://uid@other.host/some_dir
NOTE: ssh paramiko backend currently supports only the -oIdentityFile setting.
--ssl-cacert-file file
(only webdav backend) Provide a cacert file for ssl certificate verification.
See also A NOTE ON SSL CERTIFICATE VERIFICATION.
--ssl-no-check-certificate
(only webdav 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: GnuPG 2 and newer ignore this option and will always use a running gpg-agent if no
passphrase was delivered.
--use-scp
If this option is specified, then the ssh backend will use the scp protocol rather than sftp for
backend operations.
See also A NOTE ON SSH BACKENDS.
--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 25Mb.
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.
Formats of each of the URL schemes follow:
Rackspace Cloud Files
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://[relative|/absolute]/local/path
ftp[s]://user[:password]@other.host[:port]/some_dir
gdocs://user[:password]@other.host/some_dir
Google Cloud Storage
gs://bucket[/prefix]
hsi://user[:password]@other.host/some_dir
imap[s]://user[:password]@host.com[/from_address_prefix]
See also A NOTE ON IMAP
mega://user[:password]@mega.co.nz/some_dir
using rsync daemon
rsync://user[:password]@host.com[:port]::[/]module/some_dir
using rsync over ssh (only key auth)
rsync://user@host.com[:port]/[relative|/absolute]_path
s3://host/bucket_name[/prefix]
s3+http://bucket_name[/prefix]
See also A NOTE ON EUROPEAN S3 BUCKETS
scp://.. or ssh://.. are synonymous with
sftp://user[:password]@other.host[:port]/[/]some_dir
See also --ssh-backend, --ssh-askpass, --use-scp, --ssh-options and A NOTE ON SSH BACKENDS.
swift://container_name
See also A NOTE ON SWIFT (OPENSTACK OBJECT STORAGE) ACCESS
tahoe://alias/directory
Ubuntu One
u1://host_is_ignored/volume_name/sub_path
u1+http://volume_name/sub_path
See also A NOTE ON UBUNTU ONE
webdav[s]://user[:password]@other.host[:port]/some_dir
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
duplicity accepts the same file selection options rdiff-backup does, including --exclude, --exclude-
filelist-stdin, etc.
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-filelist-stdin
--exclude-globbing-filelist
--exclude-regexp
--include
--include-filelist
--include-filelist-stdin
--include-globbing-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-globbing-filelist, and exclude-globbing-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, --exclude-filelist, --include-filelist-stdin, and --exclude-filelist-stdin
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 a filelist
is interpreted similarly to the way extended shell patterns are, with a few exceptions:
1. Globbing patterns like *, **, ?, and [...] are not expanded.
2. Include patterns do not match files in a directory that is included. So /usr/local in an include
file will not match /usr/local/doc.
3. 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 neither excludes nor includes /usr/local/man, leaving the
fate of this directory to the next specification condition. Finally, it is undefined what happens with
/var. A single file list should not contain conflicting file specifications.
The --include-globbing-filelist and --exclude-globbing-filelist options also specify filelists, but each
line in the filelist will be interpreted as a globbing pattern the way --include and --exclude options
are interpreted (although "+ " and "- " prefixing is still allowed). For instance, if the file
"globbing-list.txt" contains the lines:
dir/foo
+ dir/bar
- **
Then --include-globbing-filelist globbing-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 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. "some_dir" must already exist in the Dropbox Application folder for this application, like
"Apps/Duplicity/some_dir".
2. The first run of the backend must be ineractive! It will print the URL that you need to open in
the browser to obtain OAuth token for the application. The token will be saved in the file
$HOME/.dropbox.token_store.txt and used in the future runs.
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.
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 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 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 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 two ssh backends via --ssh-backend option.
Both support --use-scp, --ssh-askpass and --ssh-options. Only the pexpect backend allows to define
--scp-command and --sftp-command.
SSH paramiko backend (selected by 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.
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 [01.2013] only in the webdav backend needs a file based
database of certification authority certificates (cacert file). It 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 four environment variables for authentification: SWIFT_USERNAME (required), SWIFT_PASSWORD
(required), SWIFT_AUTHURL (required), 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 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 UBUNTU ONE
The Ubuntu One backend in duplicity treats URLs specially: You can either use u1:// or u1+http:// in the
URL schema. With the u1 URL schema you have to give a dummy hostname (which will be ignored), followed by
your Ubuntu One volume name and path. If you use the u1+http schema, then you'll have to give only the
volume name and path in the URL.
For example, for a volume named backups containing the folder weekly, correct URLs would be
u1://ignoreme/backups/weekly/ or u1+http://backups/weekly/
To use Ubuntu One you must also have an Ubuntu One OAuth access token. Such OAuth tokens have a
practically unlimited lifetime; you can have multiple active tokens and you can revoke tokens using the
Ubuntu One web interface.
Duplicity expects the token in the environment variable FTP_PASSWORD (in the format
"consumer_key:consumer_secret:token:token_secret"). If no token is present, duplicity asks for your
Ubuntu One email address and password and requests an access token from the Ubuntu SSO service. The newly
acquired token is then printed to the console.
See https://one.ubuntu.com/ for more information about Ubuntu One.
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
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 ).
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 issue 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.
SEE ALSO
rdiffdir(1), python(1), rdiff(1), rdiff-backup(1).