rdiff-backup.1

.TH RDIFF-BACKUP 1 "MARCH 2009" "Version 1.3.3" "User Manuals" \" -*- nroff -*-
.SH NAME
rdiff-backup \- local/remote mirror and incremental backup
.SH SYNOPSIS
.B rdiff-backup
.BI [ options ]
.BI [[[ user@ ] host1.foo ]:: source_directory ]
.BI [[[ user@ ] host2.foo ]:: destination_directory ]

.B rdiff-backup
.B {{ \-l | \-\-list-increments }
.BI "| \-\-remove-older-than " time_interval
.BI "| \-\-list-at-time " time
.BI "| \-\-list-changed-since " time
.B "| \-\-list-increment-sizes "
.B "| \-\-verify"
.BI "| \-\-verify-at-time " time }
.BI [[[ user@ ] host2.foo ]:: destination_directory ]

.B rdiff-backup \-\-calculate-average
.I statfile1 statfile2 ...

.B rdiff-backup \-\-test-server
.BI [ user1 ] @host1.net1 :: path
.BI [[ user2 ] @host2.net2 :: path ]
.I ...

.SH DESCRIPTION
.B rdiff-backup
is a script, written in
.BR python (1)
that backs up one directory to another.  The target directory ends up
a copy (mirror) of the source directory, but extra reverse diffs are
stored in a special subdirectory of that target directory, so you can
still recover files lost some time ago.  The idea is to combine the
best features of a mirror and an incremental backup.  rdiff-backup
also preserves symlinks, special files, hardlinks, permissions,
uid/gid ownership, and modification times.

.B rdiff-backup
can also operate
in a bandwidth efficient manner over a pipe, like
.BR rsync (1).
Thus you can use ssh and rdiff-backup to securely back a hard drive up
to a remote location, and only the differences will be transmitted.
Using the default settings, rdiff-backup requires that the remote
system accept ssh connections, and that
.B rdiff-backup
is installed in the user's PATH on the remote system.  For information
on other options, see the section on
.B REMOTE OPERATION.

Note that you
.B should not write to the mirror directory
except with rdiff-backup.  Many of the increments are stored as
reverse diffs, so if you delete or modify a file, you may lose the
ability to restore previous versions of that file.

Finally, this man page is intended more as a precise description of
the behavior and syntax of rdiff-backup.  New users may want to check
out the examples.html file included in the rdiff-backup distribution.

.SH OPTIONS
.TP
.B \-b, \-\-backup-mode
Force backup mode even if first argument appears to be an increment or
mirror file.
.TP
.B \-\-calculate-average
Enter calculate average mode.  The arguments should be a number of
statistics files.  rdiff-backup will print the average of the listed
statistics files and exit.
.TP
.B \-\-carbonfile
Enable backup of MacOS X carbonfile information.
.TP
.B \-\-check-destination-dir
If an rdiff-backup session fails, running rdiff-backup with this
option on the destination dir will undo the failed directory.  This
happens automatically if you attempt to back up to a directory and the
last backup failed.
.TP
.B \-\-compare
This is equivalent to
.BI '\-\-compare-at-time " now" '
.TP
.BI "\-\-compare-at-time " time
Compare a directory with the backup set at the given time.  This can
be useful to see how archived data differs from current data, or to
check that a backup is current.  This only compares metadata, in the same
way rdiff-backup decides whether a file has changed.
.TP
.B \-\-compare-full
This is equivalent to
.BI '\-\-compare-full-at-time " now" '
.TP
.BI "\-\-compare-full-at-time " time
Compare a directory with the backup set at the given time.  To compare
regular files, the repository data will be copied in its entirety to
the source side and compared byte by byte.  This is the slowest but
most complete compare option.
.TP
.B \-\-compare-hash
This is equivalent to
.BI '\-\-compare-hash-at-time " now" '
.TP
.BI "\-\-compare-hash-at-time " time
Compare a directory with the backup set at the given time.  Regular
files will be compared by computing their SHA1 digest on the source
side and comparing it to the digest recorded in the metadata.
.TP
.B \-\-create-full-path
Normally only the final directory of the destination path will be
created if it does not exist. With this option, all missing directories
on the destination path will be created. Use this option with care: if
there is a typo in the remote path, the remote filesystem could fill up
very quickly (by creating a duplicate backup tree). For this reason
this option is primarily aimed at scripts which automate backups.
.TP
.BI "\-\-current-time " seconds
This option is useful mainly for testing.  If set, rdiff-backup will use
it for the current time instead of consulting the clock.  The argument
is the number of seconds since the epoch.
.TP
.BI "\-\-exclude " shell_pattern
Exclude the file or files matched by
.IR shell_pattern .
If a directory is matched, then files under that directory will also
be matched.  See the
.B FILE SELECTION
section for more information.
.TP
.B "\-\-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.
.TP
.B "\-\-exclude-fifos"
Exclude all fifo files.
.TP
.BI "\-\-exclude-filelist " filename
Excludes the files listed in
.IR filename .
If
.I filename
is handwritten you probably want
.B \-\-exclude-globbing-filelist
instead.  See the
.B FILE SELECTION
section for more information.
.TP
.B \-\-exclude-filelist-stdin
Like
.B \-\-exclude-filelist,
but the list of files will be read from standard input.  See the
.B FILE SELECTION
section for more information.
.TP
.BR "\-\-exclude-globbing-filelist " filename
Like
.B \-\-exclude-filelist
but each line of the filelist will be interpreted according to the
same rules as
.B \-\-include
and
.B \-\-exclude.
.TP
.B \-\-exclude-globbing-filelist-stdin
Like
.BR \-\-exclude-globbing-filelist ,
but the list of files will be read from standard input.
.TP
.B \-\-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.
.TP
.BI "\-\-exclude-regexp " regexp
Exclude files matching the given regexp.  Unlike the
.B \-\-exclude
option, this option does not match files in a directory it matches.
See the
.B FILE SELECTION
section for more information.
.TP
.B \-\-exclude-special-files
Exclude all device files, fifo files, socket files, and symbolic links.
.TP
.B "\-\-exclude-sockets"
Exclude all socket files.
.TP
.B "\-\-exclude-symbolic-links"
Exclude all symbolic links. This option is automatically enabled if the backup
source is running on native Windows to avoid backing-up NTFS reparse points.
.TP
.BI "\-\-exclude-if-present " filename
Exclude directories if
.IR filename
is present. This option needs to come before any other include or
exclude options.
.TP
.B \-\-force
Authorize a more drastic modification of a directory than usual (for
instance, when overwriting of a destination path, or when removing
multiple sessions with
.BR \-\-remove-older-than ).
rdiff-backup will generally tell you if it needs this.
.BR WARNING:
You can cause data loss if you mis-use this option.
Furthermore, do NOT use this option when doing a restore, as it will
DELETE FILES, unless you absolutely know what you are doing.
.TP
.BI "\-\-group-mapping-file " filename
Map group names and ids according the the group mapping file
.IR filename .
See the
.B USERS AND GROUPS
section for more information.
.TP
.BI "\-\-include " shell_pattern
Similar to
.B \-\-exclude
but include matched files instead.  Unlike
.BR \-\-exclude ,
this option will also match parent directories of matched files
(although not necessarily their contents).  See the
.B FILE SELECTION
section for more information.
.TP
.BI "\-\-include-filelist " filename
Like
.BR \-\-exclude-filelist ,
but include the listed files instead.  If
.I filename
is handwritten you probably want
.B \-\-include-globbing-filelist
instead.  See the
.B FILE SELECTION
section for more information.
.TP
.B \-\-include-filelist-stdin
Like
.BR \-\-include-filelist ,
but read the list of included files from standard input.
.TP
.BI "\-\-include-globbing-filelist " filename
Like
.B \-\-include-filelist
but each line of the filelist will be interpreted according to the
same rules as
.B \-\-include
and
.B \-\-exclude.
.TP
.B \-\-include-globbing-filelist-stdin
Like
.BR \-\-include-globbing-filelist ,
but the list of files will be read from standard input.
.TP
.BI "\-\-include-regexp " regexp
Include files matching the regular expression
.IR regexp .
Only files explicitly matched by
.I regexp
will be included by this option.  See the
.B FILE SELECTION
section for more information.
.TP
.B \-\-include-special-files
Include all device files, fifo files, socket files, and symbolic links.
.TP
.B \-\-include-symbolic-links
Include all symbolic links.
.TP
.BI "\-\-list-at-time " time
List the files in the archive that were present at the given time.  If
a directory in the archive is specified, list only the files under
that directory.
.TP
.BI "\-\-list-changed-since " time
List the files that have changed in the destination directory since
the given time.  See
.B TIME FORMATS
for the format of
.IR time .
If a directory in the archive is specified, list only the files under
that directory.  This option does not read the source directory; it is
used to compare the contents of two different rdiff-backup sessions.
.TP
.B "-l, \-\-list-increments"
List the number and date of partial incremental backups contained in
the specified destination directory.  No backup or restore will take
place if this option is given.
.TP
.B \-\-list-increment-sizes
List the total size of all the increment and mirror files by time.
This may be helpful in deciding how many increments to keep, and when
to \-\-remove-older-than.  Specifying a subdirectory is allowable; then
only the sizes of the mirror and increments pertaining to that
subdirectory will be listed.
.TP
.BI "\-\-max-file-size " size
Exclude files that are larger than the given size in bytes
.TP
.BI "\-\-min-file-size " size
Exclude files that are smaller than the given size in bytes
.TP
.B \-\-never-drop-acls
Exit with error instead of dropping acls or acl entries.  Normally
this may happen (with a warning) because the destination does not
support them or because the relevant user/group names do not exist on
the destination side.
.TP
.B \-\-no-acls
No Access Control Lists - disable backup of ACLs
.TP
.B \-\-no-carbonfile
Disable backup of MacOS X carbonfile information
.TP
.B \-\-no-compare-inode
This option prevents rdiff-backup from flagging a hardlinked file as changed
when its device number and/or inode changes.  This option is useful in
situations where the source filesystem lacks persistent device and/or inode
numbering.  For example, network filesystems may have mount-to-mount
differences in their device number (but possibly stable inode numbers);
USB/1394 devices may come up at different device numbers each remount (but
would generally have same inode number); and there are filesystems which
don't even have the same inode numbers from use to use.  Without the
option rdiff-backup may generate unnecessary numbers of tiny diff files.
.TP
.B \-\-no-compression
Disable the default gzip compression of most of the .snapshot and .diff
increment files stored in the rdiff-backup-data directory.  A backup
volume can contain compressed and uncompressed increments, so using
this option inconsistently is fine.
.TP
.B "\-\-no-compression-regexp " regexp
Do not compress increments based on files whose filenames match
regexp.  The default includes many common audiovisual and archive
files, and may be found in Globals.py.
.TP
.B \-\-no-eas
No Extended Attributes support - disable backup of EAs.
.TP
.B \-\-no-file-statistics
This will disable writing to the file_statistics file in the
rdiff-backup-data directory.  rdiff-backup will run slightly quicker
and take up a bit less space.
.TP
.BI \-\-no-hard-links
Don't replicate hard links on destination side.  If many hard-linked
files are present, this option can drastically decrease memory usage.
This option is enabled by default if the backup source or restore
destination is running on native Windows.
.TP
.B \-\-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.
.TP
.B \-\-parsable-output
If set, rdiff-backup's output will be tailored for easy parsing by
computers, instead of convenience for humans.  Currently this only
applies when listing increments using the
.B \-l
or
.B \-\-list-increments
switches, where the time will be given in seconds since the epoch.
.TP
.B \-\-override-chars-to-quote
If the filesystem to which we are backing up is not case-sensitive, automatic 'quoting' of characters occurs. For example, a file 'Developer.doc' will be converted into ';068eveloper.doc'. To override this behavior, you need to specify this option.
.TP
.B \-\-preserve-numerical-ids
If set, rdiff-backup will preserve uids/gids instead of trying to
preserve unames and gnames.  See the
.B USERS AND GROUPS
section for more information.
.TP
.B \-\-print-statistics
If set, summary statistics will be printed after a successful backup.
If not set, this information will still be available from the
session statistics file.  See the
.B STATISTICS
section for more information.
.TP
.BI "\-r, \-\-restore-as-of " restore_time
Restore the specified directory as it was as of
.IR restore_time .
See the
.B TIME FORMATS
section for more information on the format of
.IR restore_time ,
and see the
.B RESTORING
section for more information on restoring.
.TP
.BI "\-\-remote-cmd " cmd
Deprecated. Please use \-\-remote-schema instead
.TP
.BI "\-\-remote-schema " schema
Specify an alternate method of connecting to a remote computer.  This
is necessary to get rdiff-backup not to use ssh for remote backups, or
if, for instance, rdiff-backup is not in the PATH on the remote side.
See the
.B REMOTE OPERATION
section for more information.
.TP
.BI "\-\-remote-tempdir " path
Adds the \-\-tempdir option with argument
.I path
when invoking remote instances of rdiff-backup.
.TP
.BI "\-\-remove-older-than " time_spec
Remove the incremental backup information in the destination directory
that has been around longer than the given time.
.I time_spec
can be either an absolute time, like "2002-01-04", or a time interval.
The time interval is an integer followed by the character s, m, h, D,
W, M, or Y, indicating seconds, minutes, hours, days, weeks, months,
or years respectively, or a number of these concatenated.  For
example, 32m means 32 minutes, and 3W2D10h7s means 3 weeks, 2 days, 10
hours, and 7 seconds.  In this context, a month means 30 days, a year
is 365 days, and a day is always 86400 seconds.

rdiff-backup cannot remove-older-than and back up or restore in a
single session.  In order to both backup a directory and remove old
files in it, you must run rdiff-backup twice.

By default, rdiff-backup will only delete information from one session
at a time.  To remove two or more sessions at the same time, supply the
.B \-\-force
option (rdiff-backup will tell you if
.B \-\-force
is required).

Note that snapshots of deleted files are covered by this operation.
Thus if you deleted a file two weeks ago, backed up immediately
afterwards, and then ran rdiff-backup with \-\-remove-older-than 10D
today, no trace of that file would remain.  Finally, file selection
options such as \-\-include and \-\-exclude don't affect
\-\-remove-older-than.
.TP
.BI "\-\-restrict " path
Require that all file access be inside the given path.  This switch,
and the following two, are intended to be used with the \-\-server
switch to provide a bit more protection when doing automated remote
backups.  They are
.B not intended as your only line of defense
so please don't do something silly like allow public access to an
rdiff-backup server run with \-\-restrict-read-only.
.TP
.BI "\-\-restrict-read-only " path
Like
.BR \-\-restrict ,
but also reject all write requests.
.TP
.BI "\-\-restrict-update-only " path
Like
.BR \-\-restrict ,
but only allow writes as part of an incremental backup.  Requests for other types of writes (for instance, deleting
.IR path )
will be rejected.
.TP
.B \-\-server
Enter server mode (not to be invoked directly, but instead used by
another rdiff-backup process on a remote computer).
.TP
.B \-\-ssh-no-compression
When running ssh, do not use the \-C option to enable compression.
.B \-\-ssh-no-compression
is ignored if you specify a new schema using
.B \-\-remote-schema.
.TP
.BI "\-\-tempdir " path
Sets the directory that rdiff-backup uses for temporary files to
the given path. The environment variables TMPDIR, TEMP, and TMP can
also be used to set the temporary files directory. See the
documentation of the Python tempfile module for more information.
.TP
.BI "\-\-terminal-verbosity " [0-9]
Select which messages will be displayed to the terminal.  If missing
the level defaults to the verbosity level.
.TP
.B \-\-test-server
Test for the presence of a compatible rdiff-backup server as specified
in the following host::filename argument(s).  The filename section
will be ignored.
.TP
.B \-\-use-compatible-timestamps
Create timestamps in which the hour/minute/second separator is a - (hyphen)
instead of a : (colon). It is safe to use this option on one backup, and then
not use it on another; rdiff-backup supports the intermingling of different
timestamp formats. This option is enabled by default on platforms which
require that the colon be escaped.
.TP
.BI "\-\-user-mapping-file " filename
Map user names and ids according to the user mapping file
.IR filename .
See the
.B USERS AND GROUPS
section for more information.
.TP
.BI \-v [0-9] ", \-\-verbosity " [0-9]
Specify verbosity level (0 is totally silent, 3 is the default, and 9
is noisiest).  This determines how much is written to the log file.
.TP
.B \-\-verify
This is short for
.BI \-\-verify-at-time " now"
.TP
.BI \-\-verify-at-time " now"
Check all the data in the repository at the given time by computing
the SHA1 hash of all the regular files and comparing them with the
hashes stored in the metadata file.
.TP
.B "-V, \-\-version"
Print the current version and exit

.SH RESTORING
There are two ways to tell rdiff-backup to restore a file or
directory.  Firstly, you can run rdiff-backup on a mirror file and use
the
.B \-r
or
.B \-\-restore-as-of
options.  Secondly, you can run it on an increment file.
.PP
For example, suppose in the past you have run:
.PP
.RS
rdiff-backup /usr /usr.backup
.PP
.RE
to back up the /usr directory into the /usr.backup directory, and now
want a copy of the /usr/local directory the way it was 3 days ago
placed at /usr/local.old.
.PP
One way to do this is to run:
.PP
.RS
rdiff-backup \-r 3D /usr.backup/local /usr/local.old
.PP
.RE
where above the "3D" means 3 days (for other ways to specify the time,
see the
.B TIME FORMATS
section).  The /usr.backup/local directory was selected, because that
is the directory containing the current version of /usr/local.
.PP
Note that the option to
.B \-\-restore-as-of
always specifies an exact time.  (So "3D" refers to the instant 72
hours before the present.)  If there was no backup made at that time,
rdiff-backup restores the state recorded for the previous backup.  For
instance, in the above case, if "3D" is used, and there are only
backups from 2 days and 4 days ago, /usr/local as it was 4 days ago
will be restored.
.PP
The second way to restore files involves finding the corresponding
increment file.  It would be in the
/backup/rdiff-backup-data/increments/usr directory, and its name would
be something like "local.2002-11-09T12:43:53-04:00.dir" where the time
indicates it is from 3 days ago.  Note that the increment files all
end in ".diff", ".snapshot", ".dir", or ".missing", where ".missing"
just means that the file didn't exist at that time (finally, some of
these may be gzip-compressed, and have an extra ".gz" to indicate
this).  Then running:
.PP
.RS
rdiff-backup /backup/rdiff-backup-data/increments/usr/local.<time>.dir /usr/local.old
.PP
.RE
would also restore the file as desired.
.PP
If you are not sure exactly which version of a file you need, it is
probably easiest to either restore from the increments files as
described immediately above, or to see which increments are available
with \-l/\-\-list-increments, and then specify exact times into
\-r/\-\-restore-as-of.

.SH TIME FORMATS
rdiff-backup uses time strings in two places.  Firstly, all of the
increment files rdiff-backup 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.
.PP
Secondly, the
.BI \-r , " \-\-restore-as-of" ", and " \-\-remove-older-than
options take a time string, which can be given in any of several
formats:
.IP 1.
the string "now" (refers to the current time)
.IP 2.
a sequences of digits, like "123456890" (indicating the time in
seconds after the epoch)
.IP 3.
A string like "2002-01-25T07:00:00+02:00" in datetime format
.IP 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.
.IP 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 timezone settings.  For instance, "2002/3/5",
"03-05-2002", and "2002-3-05" all mean March 5th, 2002.
.IP 6.
A backup session specification which is a non-negative integer
followed by 'B'.  For instance, '0B' specifies the time of the current
mirror, and '3B' specifies the time of the 3rd newest increment.

.SH REMOTE OPERATION
In order to access remote files, rdiff-backup opens up a pipe to a
copy of rdiff-backup running on the remote machine.  Thus rdiff-backup
must be installed on both ends.  To open this pipe, rdiff-backup first
splits the filename into host_info::pathname.  It then substitutes
host_info into the remote schema, and runs the resulting command,
reading its input and output.
.PP
The default remote schema is 'ssh \-C %s rdiff-backup \-\-server' where
host_info is substituted for '%s'.  So if the host_info is
user@host.net, then rdiff-backup runs 'ssh user@host.net rdiff-backup
\-\-server'.  Using \-\-remote-schema, rdiff-backup can invoke an
arbitrary command in order to open up a remote pipe.  For instance,
.RS
rdiff-backup \-\-remote-schema 'cd /usr; %s' foo 'rdiff-backup
\-\-server'::bar
.RE
is basically equivalent to (but slower than)
.RS
rdiff-backup foo /usr/bar
.RE
.PP
Concerning quoting, if for some reason you need to put two consecutive
colons in the host_info section of a host_info::pathname argument, or
in the pathname of a local file, you can quote one of them by
prepending a backslash.  So in 'a\\::b::c', host_info is 'a::b' and
the pathname is 'c'.  Similarly, if you want to refer to a local file
whose filename contains two consecutive colons, like 'strange::file',
you'll have to quote one of the colons as in 'strange\\::file'.
Because the backslash is a quote character in these circumstances, it
too must be quoted to get a literal backslash, so 'foo\\::\\\\bar'
evaluates to 'foo::\\bar'.  To make things more complicated, because
the backslash is also a common shell quoting character, you may need
to type in '\\\\\\\\' at the shell prompt to get a literal backslash
(if it makes you feel better, I had to type in 8 backslashes to get
that in this man page...).  And finally, to include a literal % in the
string specified by \-\-remote-schema, quote it with another %, as in
%%.

Although ssh itself may be secure, using rdiff-backup in the default
way presents some security risks.  For instance if the server is run
as root, then an attacker who compromised the client could then use
rdiff-backup to overwrite arbitrary server files by "backing up" over
them.  Such a setup can be made more secure by using the sshd
configuration option
.B command="rdiff-backup \-\-server"
possibly along with the
.B \-\-restrict*
options to rdiff-backup.  For more information, see the web page, the
wiki, and the entries for the
.B \-\-restrict*
options on this man page.

.SH FILE SELECTION
.B rdiff-backup
has a number of file selection options.  When rdiff-backup is run, it
searches through the given source directory and backs up all the files
matching the specified options.  This selection system may appear
complicated, but it is supposed to be flexible and easy-to-use.  If
you just want to learn the basics, first look at the selection
examples in the examples.html file included in the package, or on the
web at
.IR http://rdiff-backup.nongnu.org/examples.html

.BR rdiff-backup 's
selection system was originally inspired by
.BR rsync (1),
but there are many differences.  (For instance, trailing backslashes
have no special significance.)

The file selection system comprises a number of file
selection conditions, which are set using one of the following command
line options:
.BR \-\-exclude ,
.BR \-\-exclude-filelist ,
.BR \-\-exclude-device-files ,
.BR \-\-exclude-fifos ,
.BR \-\-exclude-sockets ,
.BR \-\-exclude-symbolic-links ,
.BR \-\-exclude-globbing-filelist ,
.BR \-\-exclude-globbing-filelist-stdin ,
.BR \-\-exclude-filelist-stdin ,
.BR \-\-exclude-regexp ,
.BR \-\-exclude-special-files ,
.BR \-\-include ,
.BR \-\-include-filelist ,
.BR \-\-include-globbing-filelist ,
.BR \-\-include-globbing-filelist-stdin ,
.BR \-\-include-filelist-stdin ,
and
.BR \-\-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.  When backing up, if
a file is excluded, rdiff-backup acts as if that file does not exist
in the source directory.  When restoring, an excluded file is
considered not to exist in either the source or target directories.

For instance,
.PP
.RS
rdiff-backup \-\-include /usr \-\-exclude /usr /usr /backup
.PP
.RE
is exactly the same as
.PP
.RS
rdiff-backup /usr /backup
.PP
.RE
because the include and exclude directives match exactly the same
files, and the
.B \-\-include
comes first, giving it precedence.  Similarly,
.PP
.RS
rdiff-backup \-\-include /usr/local/bin \-\-exclude /usr/local /usr /backup
.PP
.RE
would backup the /usr/local/bin directory (and its contents), but not
/usr/local/doc.

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

If you need to match filenames which contain the above globbing
characters, they may be escaped using a backslash "\\". The backslash
will only escape the character following it so for
.B **
you will need
to use "\\*\\*" to avoid escaping it to the
.B *
globbing character.

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 rdiff-backup sees them.

The
.BI "\-\-exclude " pattern
option matches a file iff:
.TP
.B 1.
.I pattern
can be expanded into the file's filename, or
.TP
.B 2.
the file is inside a directory matched by the option.
.PP
.RE
Conversely,
.BI "\-\-include " pattern
matches a file iff:
.TP
.B 1.
.I pattern
can be expanded into the file's filename,
.TP
.B 2.
the file is inside a directory matched by the option, or
.TP
.B 3.
the file is a directory which contains a file matched by the option.
.PP
.RE
For example,
.PP
.RS
.B \-\-exclude
/usr/local
.PP
.RE
matches /usr/local, /usr/local/lib, and /usr/local/lib/netscape.  It
is the same as \-\-exclude /usr/local \-\-exclude '/usr/local/**'.
.PP
.RS
.B \-\-include
/usr/local
.PP
.RE
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,
.PP
.RS
.B \-\-include
ignorecase:'/usr/[a-z0-9]foo/*/**.py'
.PP
.RE
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.

The
.BR \-\-include-filelist ,
.BR \-\-exclude-filelist ,
.BR \-\-include-filelist-stdin ,
and
.B \-\-exclude-filelist-stdin
options also introduce file selection conditions.  They direct
rdiff-backup 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
.I extended shell patterns
are, with a few exceptions:
.TP
.B 1.
Globbing patterns like
.BR * ,
.BR ** ,
.BR ? ,
and
.B [...]
are not expanded.
.TP
.B 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.
.TP
.B 3.
Lines starting with "+ " are interpreted as include directives, even
if found in a filelist referenced by
.BR \-\-exclude-filelist .
Similarly, lines starting with "- " exclude files even if they are
found within an include filelist.

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

.RS
/usr/local
.RE
.RS
- /usr/local/doc
.RE
.RS
/usr/local/bin
.RE
.RS
+ /var
.RE
.RS
- /var

.RE
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
.B \-\-include-globbing-filelist
and
.B \-\-exclude-globbing-filelist
options also specify filelists, but each line in the filelist will be
interpreted as a globbing pattern the way
.B \-\-include
and
.B \-\-exclude
options are interpreted (although "+ " and "- " prefixing is still
allowed).  For instance, if the file "globbing-list.txt" contains the
lines:

.RE
.RS
dir/foo
.RE
.RS
+ dir/bar
.RE
.RS
- **

.RE
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
.B \-\-include-regexp
and
.B \-\-exclude-regexp
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
.B \-\-include
and
.B \-\-exclude
options, the regular expression options don't match files containing
or contained in matched files.  So for instance
.PP
.RS
\-\-include '[0-9]{7}(?!foo)'
.PP
.RE
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.

.SH USERS AND GROUPS
There can be complications preserving ownership across systems.  For
instance the username that owns a file on the source system may not
exist on the destination.  Here is how rdiff-backup maps ownership on
the source to the destination (or vice-versa, in the case of restoring):

.TP
.B 1.
If the \-\-preserve-numerical-ids option is given, the remote files will
always have the same uid and gid, both for ownership and ACL entries.
This may cause unames and gnames to change.
.TP
.B 2.
Otherwise, attempt to preserve the user and group names for ownership
and in ACLs.  This may result in files having different uids and gids
across systems.
.TP
.B 3.
If a name cannot be preserved (e.g. because the username does not
exist), preserve the original id, but only in cases of user and group
ownership.  For ACLs, omit any entry that has a bad user or group
name.
.TP
.B 4.
The
.B \-\-user-mapping-file
and
.B \-\-group-mapping-file
options override this behavior.  If either of these options is given,
the policy described in 2 and 3 above will be followed, but with the
mapped user and group instead of the original.  If you specify both
.B \-\-preserve-numerical-ids
and one of the mapping options, the behavior is undefined.

.RE
The user and group mapping files both have the same form:

.RS
old_name_or_id1:new_name_or_id1
.RE
.RS
old_name_or_id2:new_name_or_id2
.RE
.RS
<etc>
.RE

Each line should contain a name or id, followed by a colon ":",
followed by another name or id.  If a name or id is not listed, they
are treated in the default way described above.

When restoring, the above behavior is also followed, but note that the
original source user/group information will be the input, not the
already mapped user/group information present in the backup
repository.  For instance, suppose you have mapped all the files owned
by
.I alice
in the source so that they are owned by
.I ben
in the repository, and now you want to restore, making sure the files owned originally by
.I alice
are still owned by
.IR alice .
In this case there is no need to use any of the mapping options.
However, if you wanted to restore the files so that the files
originally owned by
.I alice
on the source are now owned by
.IR ben ,
you would have to use the mapping options, even though you just want
the unames of the repository's files preserved in the restored files.


.SH STATISTICS
Every session rdiff-backup saves various statistics into two files,
the session statistics file at
rdiff-backup-data/session_statistics.<time>.data and the directory
statistics file at rdiff-backup-data/directory_statistics.<time>.data.
They are both text files and contain similar information: how many
files changed, how many were deleted, the total size of increment
files created, etc.  However, the session statistics file is intended
to be very readable and only describes the session as a whole.  The
directory statistics file is more compact (and slightly less readable)
but describes every directory backed up.  It also may be compressed to
save space.

Statistics\-related options include
.B \-\-print-statistics
and
.BR \-\-null-separator .

Also, rdiff-backup will save various messages to the log file, which
is rdiff-backup-data/backup.log for backup sessions and
rdiff-backup-data/restore.log for restore sessions.  Generally what is
written to this file will coincide with the messages displayed to
stdout or stderr, although this can be changed with the
.B \-\-terminal-verbosity
option.

The log file is not compressed and can become quite large if
rdiff-backup is run with high verbosity.

.SH EXIT STATUS
If rdiff-backup finishes successfully, the exit status will be 0.  If
there is an unrecoverable (critical) error, it will be non-zero
(usually 1, but don't depend on this specific value).  When setting up
rdiff-backup to run automatically (as from
.BR cron (8)
or similar) it is probably a good idea to check the exit code.

.SH BUGS
The gzip library in versions 2.2 and earlier of python (but fixed in
2.3a1) has trouble producing files over 2GB in length.  This bug will
prevent rdiff-backup from producing large compressed increments
(snapshots or diffs).  A workaround is to disable compression for
large uncompressable files.

.SH AUTHOR
Ben Escoto <ben@emerose.org>
.PP
Feel free to ask me questions or send me bug reports, but you may want to see the web page, mentioned below, first.

.SH SEE ALSO
.BR python (1),
.BR rdiff (1),
.BR rsync (1),
.BR ssh (1).
The main rdiff-backup web page is at
.IR https://rdiff-backup.net/ .
It has more information, links to the mailing list and CVS, etc.