Check the return value of flush_write_file() and report an error

[rsync/rsync.git] / rsync.yo

mailto(rsync-bugs@samba.org)
manpage(rsync)(1)(30 Sep 2004)()()
manpagename(rsync)(faster, flexible replacement for rcp)
manpagesynopsis()

rsync [OPTION]... SRC [SRC]... [USER@]HOST:DEST

rsync [OPTION]... [USER@]HOST:SRC DEST

rsync [OPTION]... SRC [SRC]... DEST

rsync [OPTION]... [USER@]HOST::SRC [DEST]

rsync [OPTION]... SRC [SRC]... [USER@]HOST::DEST

rsync [OPTION]... rsync://[USER@]HOST[:PORT]/SRC [DEST]

rsync [OPTION]... SRC [SRC]... rsync://[USER@]HOST[:PORT]/DEST

manpagedescription()

rsync is a program that behaves in much the same way that rcp does,
but has many more options and uses the rsync remote-update protocol to
greatly speed up file transfers when the destination file is being
updated.

The rsync remote-update protocol allows rsync to transfer just the
differences between two sets of files across the network connection, using
an efficient checksum-search algorithm described in the technical
report that accompanies this package.

Some of the additional features of rsync are:

itemize(
  it() support for copying links, devices, owners, groups, and permissions
  it() exclude and exclude-from options similar to GNU tar
  it() a CVS exclude mode for ignoring the same files that CVS would ignore
  it() can use any transparent remote shell, including ssh or rsh
  it() does not require root privileges
  it() pipelining of file transfers to minimize latency costs
  it() support for anonymous or authenticated rsync servers (ideal for
       mirroring)
)

manpagesection(GENERAL)

There are eight different ways of using rsync. They are:

itemize(
	it() for copying local files. This is invoked when neither
	     source nor destination path contains a : separator

	it() for copying from the local machine to a remote machine using
	a remote shell program as the transport (such as ssh or
	rsh). This is invoked when the destination path contains a
	single : separator.

	it() for copying from a remote machine to the local machine
	using a remote shell program. This is invoked when the source
	contains a : separator.

	it() for copying from a remote rsync server to the local
	machine. This is invoked when the source path contains a ::
	separator or an rsync:// URL.

	it() for copying from the local machine to a remote rsync
	server. This is invoked when the destination path contains a ::
	separator or an rsync:// URL.

	it() for copying from a remote machine using a remote shell
	program as the transport, using rsync server on the remote
	machine.  This is invoked when the source path contains a ::
	separator and the --rsh=COMMAND (aka "-e COMMAND") option is
	also provided.

	it() for copying from the local machine to a remote machine
	using a remote shell program as the transport, using rsync
	server on the remote machine.  This is invoked when the
	destination path contains a :: separator and the
	--rsh=COMMAND option is also provided.

	it() for listing files on a remote machine. This is done the
	same way as rsync transfers except that you leave off the
	local destination.  
)

Note that in all cases (other than listing) at least one of the source
and destination paths must be local.

manpagesection(SETUP)

See the file README for installation instructions.

Once installed, you can use rsync to any machine that you can access via
a remote shell (as well as some that you can access using the rsync
daemon-mode protocol).  For remote transfers, a modern rsync uses ssh
for its communications, but it may have been configured to use a
different remote shell by default, such as rsh or remsh.

You can also specify any remote shell you like, either by using the -e
command line option, or by setting the RSYNC_RSH environment variable.

One common substitute is to use ssh, which offers a high degree of
security.

Note that rsync must be installed on both the source and destination
machines. 

manpagesection(USAGE)

You use rsync in the same way you use rcp. You must specify a source
and a destination, one of which may be remote.

Perhaps the best way to explain the syntax is with some examples:

quote(rsync -t *.c foo:src/)

This would transfer all files matching the pattern *.c from the
current directory to the directory src on the machine foo. If any of
the files already exist on the remote system then the rsync
remote-update protocol is used to update the file by sending only the
differences. See the tech report for details.

quote(rsync -avz foo:src/bar /data/tmp)

This would recursively transfer all files from the directory src/bar on the
machine foo into the /data/tmp/bar directory on the local machine. The
files are transferred in "archive" mode, which ensures that symbolic
links, devices, attributes, permissions, ownerships, etc. are preserved
in the transfer.  Additionally, compression will be used to reduce the
size of data portions of the transfer.

quote(rsync -avz foo:src/bar/ /data/tmp)

A trailing slash on the source changes this behavior to avoid creating an
additional directory level at the destination.  You can think of a trailing
/ on a source as meaning "copy the contents of this directory" as opposed
to "copy the directory by name", but in both cases the attributes of the
containing directory are transferred to the containing directory on the
destination.  In other words, each of the following commands copies the
files in the same way, including their setting of the attributes of
/dest/foo:

quote(rsync -av /src/foo /dest)
quote(rsync -av /src/foo/ /dest/foo)

You can also use rsync in local-only mode, where both the source and
destination don't have a ':' in the name. In this case it behaves like
an improved copy command.

quote(rsync somehost.mydomain.com::)

This would list all the anonymous rsync modules available on the host
somehost.mydomain.com.  (See the following section for more details.)


manpagesection(ADVANCED USAGE)

The syntax for requesting multiple files from a remote host involves using
quoted spaces in the SRC.  Some examples:

quote(rsync host::'modname/dir1/file1 modname/dir2/file2' /dest)

This would copy file1 and file2 into /dest from an rsync daemon.  Each
additional arg must include the same "modname/" prefix as the first one,
and must be preceded by a single space.  All other spaces are assumed
to be a part of the filenames.

quote(rsync -av host:'dir1/file1 dir2/file2' /dest)

This would copy file1 and file2 into /dest using a remote shell.  This
word-splitting is done by the remote shell, so if it doesn't work it means
that the remote shell isn't configured to split its args based on
whitespace (a very rare setting, but not unknown).  If you need to transfer
a filename that contains whitespace, you'll need to either escape the
whitespace in a way that the remote shell will understand, or use wildcards
in place of the spaces.  Two examples of this are:

quote(rsync -av host:'file\ name\ with\ spaces' /dest)
quote(rsync -av host:file?name?with?spaces /dest)

This latter example assumes that your shell passes through unmatched
wildcards.  If it complains about "no match", put the name in quotes.


manpagesection(CONNECTING TO AN RSYNC SERVER)

It is also possible to use rsync without a remote shell as the
transport. In this case you will connect to a remote rsync server
running on TCP port 873. 

You may establish the connection via a web proxy by setting the
environment variable RSYNC_PROXY to a hostname:port pair pointing to
your web proxy.  Note that your web proxy's configuration must support
proxy connections to port 873.

Using rsync in this way is the same as using it with a remote shell except
that:

itemize(
	it() you use a double colon :: instead of a single colon to
	separate the hostname from the path or an rsync:// URL.

	it() the remote server may print a message of the day when you
	connect.

	it() if you specify no path name on the remote server then the
	list of accessible paths on the server will be shown.

	it() if you specify no local destination then a listing of the
	specified files on the remote server is provided.
)

Some paths on the remote server may require authentication. If so then
you will receive a password prompt when you connect. You can avoid the
password prompt by setting the environment variable RSYNC_PASSWORD to
the password you want to use or using the --password-file option. This
may be useful when scripting rsync.

WARNING: On some systems environment variables are visible to all
users. On those systems using --password-file is recommended.

manpagesection(CONNECTING TO AN RSYNC SERVER OVER A REMOTE SHELL PROGRAM)

It is sometimes useful to be able to set up file transfers using rsync
server capabilities on the remote machine, while still using ssh or
rsh for transport.  This is especially useful when you want to connect
to a remote machine via ssh (for encryption or to get through a
firewall), but you still want to have access to the rsync server
features (see RUNNING AN RSYNC SERVER OVER A REMOTE SHELL PROGRAM,
below).  

From the user's perspective, using rsync in this way is the same as
using it to connect to an rsync server, except that you must
explicitly set the remote shell program on the command line with
--rsh=COMMAND.  (Setting RSYNC_RSH in the environment will not turn on
this functionality.)

In order to distinguish between the remote-shell user and the rsync
server user, you can use '-l user' on your remote-shell command:

quote(rsync -av --rsh="ssh -l ssh-user" rsync-user@host::module[/path] local-path)

The "ssh-user" will be used at the ssh level; the "rsync-user" will be
used to check against the rsyncd.conf on the remote host.

manpagesection(RUNNING AN RSYNC SERVER)

An rsync server is configured using a configuration file.  Please see the 
rsyncd.conf(5) man page for more information.  By default the configuration
file is called /etc/rsyncd.conf, unless rsync is running over a remote
shell program and is not running as root; in that case, the default name
is rsyncd.conf in the current directory on the remote computer 
(typically $HOME).

manpagesection(RUNNING AN RSYNC SERVER OVER A REMOTE SHELL PROGRAM)

See the rsyncd.conf(5) man page for full information on the rsync
server configuration file.  

Several configuration options will not be available unless the remote
user is root (e.g. chroot, setuid/setgid, etc.).  There is no need to
configure inetd or the services map to include the rsync server port
if you run an rsync server only via a remote shell program.

To run an rsync server out of a single-use ssh key, see this section
in the rsyncd.conf(5) man page.

manpagesection(EXAMPLES)

Here are some examples of how I use rsync.

To backup my wife's home directory, which consists of large MS Word
files and mail folders, I use a cron job that runs

quote(rsync -Cavz . arvidsjaur:backup)

each night over a PPP connection to a duplicate directory on my machine
"arvidsjaur".

To synchronize my samba source trees I use the following Makefile
targets:

quote(      get:nl()
       rsync -avuzb --exclude '*~' samba:samba/ .

      put:nl()
       rsync -Cavuzb . samba:samba/

      sync: get put)

this allows me to sync with a CVS directory at the other end of the
connection. I then do cvs operations on the remote machine, which saves a
lot of time as the remote cvs protocol isn't very efficient.

I mirror a directory between my "old" and "new" ftp sites with the
command

quote(rsync -az -e ssh --delete ~ftp/pub/samba/ nimbus:"~ftp/pub/tridge/samba")

this is launched from cron every few hours.

manpagesection(OPTIONS SUMMARY)

Here is a short summary of the options available in rsync. Please refer
to the detailed description below for a complete description.

verb(
 -v, --verbose               increase verbosity
 -q, --quiet                 decrease verbosity
 -c, --checksum              always checksum
 -a, --archive               archive mode, equivalent to -rlptgoD
 -r, --recursive             recurse into directories
 -R, --relative              use relative path names
     --no-relative           turn off --relative
     --no-implied-dirs       don't send implied dirs with -R
 -b, --backup                make backups (see --suffix & --backup-dir)
     --backup-dir            make backups into this directory
     --suffix=SUFFIX         backup suffix (default ~ w/o --backup-dir)
 -u, --update                update only (don't overwrite newer files)
     --inplace               update the destination files inplace
 -K, --keep-dirlinks         treat symlinked dir on receiver as dir
 -l, --links                 copy symlinks as symlinks
 -L, --copy-links            copy the referent of all symlinks
     --copy-unsafe-links     copy the referent of "unsafe" symlinks
     --safe-links            ignore "unsafe" symlinks
 -H, --hard-links            preserve hard links
 -p, --perms                 preserve permissions
 -o, --owner                 preserve owner (root only)
 -g, --group                 preserve group
 -D, --devices               preserve devices (root only)
 -t, --times                 preserve times
 -S, --sparse                handle sparse files efficiently
 -n, --dry-run               show what would have been transferred
 -W, --whole-file            copy whole files, no incremental checks
     --no-whole-file         turn off --whole-file
 -x, --one-file-system       don't cross filesystem boundaries
 -B, --block-size=SIZE       force a fixed checksum block-size
 -e, --rsh=COMMAND           specify the remote shell
     --rsync-path=PATH       specify path to rsync on the remote machine
     --existing              only update files that already exist
     --ignore-existing       ignore files that already exist on receiver
     --delete                delete files that don't exist on sender
     --delete-excluded       also delete excluded files on receiver
     --delete-after          receiver deletes after transfer, not before
     --ignore-errors         delete even if there are I/O errors
     --max-delete=NUM        don't delete more than NUM files
     --max-size=SIZE         don't transfer any file larger than SIZE
     --partial               keep partially transferred files
     --partial-dir=DIR       put a partially transferred file into DIR
     --force                 force deletion of dirs even if not empty
     --numeric-ids           don't map uid/gid values by user/group name
     --timeout=TIME          set I/O timeout in seconds
 -I, --ignore-times          turn off mod time & file size quick check
     --size-only             ignore mod time for quick check (use size)
     --modify-window=NUM     compare mod times with reduced accuracy
 -T  --temp-dir=DIR          create temporary files in directory DIR
     --compare-dest=DIR      also compare received files relative to DIR
     --copy-dest=DIR         ... and include copies of unchanged files
     --link-dest=DIR         hardlink to files in DIR when unchanged
 -P                          equivalent to --partial --progress
 -z, --compress              compress file data
 -C, --cvs-exclude           auto ignore files in the same way CVS does
     --exclude=PATTERN       exclude files matching PATTERN
     --exclude-from=FILE     exclude patterns listed in FILE
     --include=PATTERN       don't exclude files matching PATTERN
     --include-from=FILE     don't exclude patterns listed in FILE
     --files-from=FILE       read FILE for list of source-file names
 -0  --from0                 all file lists are delimited by nulls
     --version               print version number
     --blocking-io           use blocking I/O for the remote shell
     --no-blocking-io        turn off --blocking-io
     --stats                 give some file transfer stats
     --progress              show progress during transfer
     --log-format=FORMAT     log file transfers using specified format
     --password-file=FILE    get password from FILE
     --bwlimit=KBPS          limit I/O bandwidth, KBytes per second
     --write-batch=FILE      write a batch to FILE 
     --read-batch=FILE       read a batch from FILE
     --checksum-seed=NUM     set block/file checksum seed
 -4  --ipv4                  prefer IPv4
 -6  --ipv6                  prefer IPv6
 -h, --help                  show this help screen
)

Rsync can also be run as a daemon, in which case the following options are accepted:

verb(
     --daemon                run as an rsync daemon
     --address=ADDRESS       bind to the specified address
     --bwlimit=KBPS          limit I/O bandwidth, KBytes per second
     --config=FILE           specify alternate rsyncd.conf file
     --no-detach             do not detach from the parent
     --port=PORT             specify alternate rsyncd port number
 -4  --ipv4                  prefer IPv4
 -6  --ipv6                  prefer IPv6
 -h, --help                  show this help screen
)

manpageoptions()

rsync uses the GNU long options package. Many of the command line
options have two variants, one short and one long.  These are shown
below, separated by commas. Some options only have a long variant.
The '=' for options that take a parameter is optional; whitespace
can be used instead.

startdit()
dit(bf(-h, --help)) Print a short help page describing the options
available in rsync.

dit(bf(--version)) print the rsync version number and exit.

dit(bf(-v, --verbose)) This option increases the amount of information you
are given during the transfer.  By default, rsync works silently. A
single -v will give you information about what files are being
transferred and a brief summary at the end. Two -v flags will give you
information on what files are being skipped and slightly more
information at the end. More than two -v flags should only be used if
you are debugging rsync.

dit(bf(-q, --quiet)) This option decreases the amount of information you
are given during the transfer, notably suppressing information messages
from the remote server. This flag is useful when invoking rsync from
cron.

dit(bf(-I, --ignore-times)) Normally rsync will skip any files that are
already the same size and have the same modification time-stamp.
This option turns off this "quick check" behavior.

dit(bf(--size-only)) Normally rsync will not transfer any files that are
already the same size and have the same modification time-stamp. With the
--size-only option, files will not be transferred if they have the same size,
regardless of timestamp. This is useful when starting to use rsync
after using another mirroring system which may not preserve timestamps
exactly.

dit(bf(--modify-window)) When comparing two timestamps rsync treats
the timestamps as being equal if they are within the value of
modify_window. This is normally zero, but you may find it useful to
set this to a larger value in some situations. In particular, when
transferring to Windows FAT filesystems which cannot represent times
with a 1 second resolution --modify-window=1 is useful.

dit(bf(-c, --checksum)) This forces the sender to checksum all files using
a 128-bit MD4 checksum before transfer. The checksum is then
explicitly checked on the receiver and any files of the same name
which already exist and have the same checksum and size on the
receiver are not transferred.  This option can be quite slow.

dit(bf(-a, --archive)) This is equivalent to -rlptgoD. It is a quick
way of saying you want recursion and want to preserve almost
everything.  

Note however that bf(-a) bf(does not preserve hardlinks), because
finding multiply-linked files is expensive.  You must separately
specify bf(-H).

dit(bf(-r, --recursive)) This tells rsync to copy directories
recursively. If you don't specify this then rsync won't copy
directories at all.

dit(bf(-R, --relative)) Use relative paths. This means that the full path
names specified on the command line are sent to the server rather than
just the last parts of the filenames. This is particularly useful when
you want to send several different directories at the same time. For
example, if you used the command

verb(rsync foo/bar/foo.c remote:/tmp/)

then this would create a file called foo.c in /tmp/ on the remote
machine. If instead you used

verb(rsync -R foo/bar/foo.c remote:/tmp/)

then a file called /tmp/foo/bar/foo.c would be created on the remote
machine -- the full path name is preserved.

dit(bf(--no-relative)) Turn off the --relative option.  This is only
needed if you want to use --files-from without its implied --relative
file processing.

dit(bf(--no-implied-dirs)) When combined with the --relative option, the
implied directories in each path are not explicitly duplicated as part
of the transfer.  This makes the transfer more optimal and also allows
the two sides to have non-matching symlinks in the implied part of the
path.  For instance, if you transfer the file "/path/foo/file" with -R,
the default is for rsync to ensure that "/path" and "/path/foo" on the
destination exactly match the directories/symlinks of the source.  Using
the --no-implied-dirs option would omit both of these implied dirs,
which means that if "/path" was a real directory on one machine and a
symlink of the other machine, rsync would not try to change this.

dit(bf(-b, --backup)) With this option, preexisting destination files are
renamed as each file is transferred or deleted.  You can control where the
backup file goes and what (if any) suffix gets appended using the
--backup-dir and --suffix options.

dit(bf(--backup-dir=DIR)) In combination with the --backup option, this
tells rsync to store all backups in the specified directory. This is
very useful for incremental backups.  You can additionally
specify a backup suffix using the --suffix option
(otherwise the files backed up in the specified directory
will keep their original filenames).
If DIR is a relative path, it is relative to the destination directory
(which changes in a recursive transfer).

dit(bf(--suffix=SUFFIX)) This option allows you to override the default
backup suffix used with the --backup (-b) option. The default suffix is a ~
if no --backup-dir was specified, otherwise it is an empty string.

dit(bf(-u, --update)) This forces rsync to skip any files which exist on
the destination and have a modified time that is newer than the source
file.  (If an existing destination file has a modify time equal to the
source file's, it will be updated if the sizes are different.)

In the current implementation of --update, a difference of file format
between the sender and receiver is always
considered to be important enough for an update, no matter what date
is on the objects.  In other words, if the source has a directory or a
symlink where the destination has a file, the transfer would occur
regardless of the timestamps.  This might change in the future (feel
free to comment on this on the mailing list if you have an opinion).

dit(bf(-K, --keep-dirlinks)) On the receiving side, if a symlink is
pointing to a directory, it will be treated as matching a directory
from the sender.

dit(bf(--inplace)) This causes rsync not to create a new copy of the file
and then move it into place.  Instead rsync will overwrite the existing
file, meaning that the rsync algorithm can't extract the full amount of
network reduction it might otherwise (since it does not yet try to sort
data matches -- a future version may improve this).

This option is useful for transfer of large files with block-based changes
or appended data, and also on systems that are disk bound, not network
bound.

The option implies --partial (since an interrupted transfer does not delete
the file), but conflicts with --partial-dir, --compare-dest, --copy-dest, and
--link-dest (a future rsync version will hopefully update the protocol to
remove some of these restrictions).

WARNING: The file's data will be in an inconsistent state during the
transfer (and possibly afterward if the transfer gets interrupted), so you
should not use this option to update files that are in use.  Also note that
rsync will be unable to update a file inplace that is not writable by the
receiving user.

dit(bf(-l, --links)) When symlinks are encountered, recreate the
symlink on the destination.

dit(bf(-L, --copy-links)) When symlinks are encountered, the file that
they point to (the referent) is copied, rather than the symlink.  In older
versions of rsync, this option also had the side-effect of telling the
receiving side to follow symlinks, such as symlinks to directories.  In a
modern rsync such as this one, you'll need to specify --keep-dirlinks (-K)
to get this extra behavior.  The only exception is when sending files to
an rsync that is too old to understand -K -- in that case, the -L option
will still have the side-effect of -K on that older receiving rsync.

dit(bf(--copy-unsafe-links)) This tells rsync to copy the referent of
symbolic links that point outside the copied tree.  Absolute symlinks
are also treated like ordinary files, and so are any symlinks in the
source path itself when --relative is used.

dit(bf(--safe-links)) This tells rsync to ignore any symbolic links
which point outside the copied tree. All absolute symlinks are
also ignored. Using this option in conjunction with --relative may
give unexpected results. 

dit(bf(-H, --hard-links)) This tells rsync to recreate hard  links  on
the  remote system  to  be the same as the local system. Without this
option hard links are treated like regular files.

Note that rsync can only detect hard links if both parts of the link
are in the list of files being sent.

This option can be quite slow, so only use it if you need it.

dit(bf(-W, --whole-file)) With this option the incremental rsync algorithm
is not used and the whole file is sent as-is instead.  The transfer may be
faster if this option is used when the bandwidth between the source and
destination machines is higher than the bandwidth to disk (especially when the
"disk" is actually a networked filesystem).  This is the default when both
the source and destination are specified as local paths.

dit(bf(--no-whole-file)) Turn off --whole-file, for use when it is the
default.

dit(bf(-p, --perms)) This option causes rsync to set the destination
permissions to be the same as the source permissions.

Without this option, each new file gets its permissions set based on the
source file's permissions and the umask at the receiving end, while all
other files (including updated files) retain their existing permissions
(which is the same behavior as other file-copy utilities, such as cp).

dit(bf(-o, --owner)) This option causes rsync to set the owner of the
destination file to be the same as the source file.  On most systems,
only the super-user can set file ownership.  By default, the preservation
is done by name, but may fall back to using the ID number in some
circumstances.  See the --numeric-ids option for a full discussion.

dit(bf(-g, --group)) This option causes rsync to set the group of the
destination file to be the same as the source file.  If the receiving
program is not running as the super-user, only groups that the
receiver is a member of will be preserved.  By default, the preservation
is done by name, but may fall back to using the ID number in some
circumstances.  See the --numeric-ids option for a full discussion.

dit(bf(-D, --devices)) This option causes rsync to transfer character and
block device information to the remote system to recreate these
devices. This option is only available to the super-user.

dit(bf(-t, --times)) This tells rsync to transfer modification times along
with the files and update them on the remote system.  Note that if this
option is not used, the optimization that excludes files that have not been
modified cannot be effective; in other words, a missing -t or -a will
cause the next transfer to behave as if it used -I, causing all files to be
updated (though the rsync algorithm will make the update fairly efficient
if the files haven't actually changed, you're much better off using -t).

dit(bf(-n, --dry-run)) This tells rsync to not do any file transfers,
instead it will just report the actions it would have taken.

dit(bf(-S, --sparse)) Try to handle sparse files efficiently so they take
up less space on the destination.

NOTE: Don't use this option when the destination is a Solaris "tmpfs"
filesystem. It doesn't seem to handle seeks over null regions
correctly and ends up corrupting the files.

dit(bf(-x, --one-file-system)) This tells rsync not to cross filesystem
boundaries  when recursing.  This  is useful for transferring the
contents of only one filesystem.

dit(bf(--existing)) This tells rsync not to create any new files -
only update files that already exist on the destination.

dit(bf(--ignore-existing))
This tells rsync not to update files that already exist on 
the destination. 

dit(bf(--max-delete=NUM)) This tells rsync not to delete more than NUM
files or directories. This is useful when mirroring very large trees
to prevent disasters.

dit(bf(--max-size=SIZE)) This tells rsync to avoid transferring any
file that is larger than the specified SIZE. The SIZE value can be
suffixed with a letter to indicate a size multiplier (K, M, or G) and
may be a fractional value (e.g. "--max-size=1.5m").

dit(bf(--delete)) This tells rsync to delete any files on the receiving
side that aren't on the sending side.   Files that are excluded from
transfer are excluded from being deleted unless you use --delete-excluded.

This option has no effect if directory recursion is not selected.

This option can be dangerous if used incorrectly!  It is a very good idea
to run first using the dry run option (-n) to see what files would be
deleted to make sure important files aren't listed.

If the sending side detects any I/O errors then the deletion of any
files at the destination will be automatically disabled. This is to
prevent temporary filesystem failures (such as NFS errors) on the
sending side causing a massive deletion of files on the
destination.  You can override this with the --ignore-errors option.

dit(bf(--delete-excluded)) In addition to deleting the files on the
receiving side that are not on the sending side, this tells rsync to also
delete any files on the receiving side that are excluded (see --exclude).
Implies --delete.

dit(bf(--delete-after)) By default rsync does file deletions on the
receiving side before transferring files to try to ensure that there is
sufficient space on the receiving filesystem. If you want to delete
after transferring, use the --delete-after switch. Implies --delete.

dit(bf(--ignore-errors)) Tells --delete to go ahead and delete files
even when there are I/O errors.

dit(bf(--force)) This options tells rsync to delete directories even if
they are not empty when they are to be replaced by non-directories.  This
is only relevant without --delete because deletions are now done depth-first.
Requires the --recursive option (which is implied by -a) to have any effect.

dit(bf(-B, --block-size=BLOCKSIZE)) This forces the block size used in
the rsync algorithm to a fixed value.  It is normally selected based on
the size of each file being updated.  See the technical report for details.

dit(bf(-e, --rsh=COMMAND)) This option allows you to choose an alternative
remote shell program to use for communication between the local and
remote copies of rsync. Typically, rsync is configured to use ssh by
default, but you may prefer to use rsh on a local network.

If this option is used with bf([user@]host::module/path), then the
remote shell em(COMMAND) will be used to run an rsync server on the
remote host, and all data will be transmitted through that remote
shell connection, rather than through a direct socket connection to a
running rsync server on the remote host.  See the section "CONNECTING
TO AN RSYNC SERVER OVER A REMOTE SHELL PROGRAM" above.

Command-line arguments are permitted in COMMAND provided that COMMAND is
presented to rsync as a single argument.  For example:

quote(-e "ssh -p 2234")

(Note that ssh users can alternately customize site-specific connect
options in their .ssh/config file.)

You can also choose the remote shell program using the RSYNC_RSH
environment variable, which accepts the same range of values as -e.

See also the --blocking-io option which is affected by this option.

dit(bf(--rsync-path=PATH)) Use this to specify the path to the copy of
rsync on the remote machine. Useful when it's not in your path. Note
that this is the full path to the binary, not just the directory that
the binary is in.

dit(bf(-C, --cvs-exclude)) This is a useful shorthand for excluding a
broad range of files that you often don't want to transfer between
systems. It uses the same algorithm that CVS uses to determine if
a file should be ignored.

The exclude list is initialized to:

quote(RCS SCCS CVS CVS.adm RCSLOG cvslog.* tags TAGS .make.state
.nse_depinfo *~ #* .#* ,* _$* *$ *.old *.bak *.BAK *.orig *.rej
.del-* *.a *.olb *.o *.obj *.so *.exe *.Z *.elc *.ln core .svn/)

then files listed in a $HOME/.cvsignore are added to the list and any
files listed in the CVSIGNORE environment variable (all cvsignore names
are delimited by whitespace).

Finally, any file is ignored if it is in the same directory as a
.cvsignore file and matches one of the patterns listed therein.
See the bf(cvs(1)) manual for more information.

dit(bf(--exclude=PATTERN)) This option allows you to selectively exclude
certain files from the list of files to be transferred. This is most
useful in combination with a recursive transfer.

You may use as many --exclude options on the command line as you like
to build up the list of files to exclude.

See the EXCLUDE PATTERNS section for detailed information on this option.

dit(bf(--exclude-from=FILE)) This option is similar to the --exclude
option, but instead it adds all exclude patterns listed in the file
FILE to the exclude list.  Blank lines in FILE and lines starting with
';' or '#' are ignored.
If em(FILE) is bf(-) the list will be read from standard input.

dit(bf(--include=PATTERN)) This option tells rsync to not exclude the
specified pattern of filenames. This is useful as it allows you to
build up quite complex exclude/include rules.

See the EXCLUDE PATTERNS section for detailed information on this option.

dit(bf(--include-from=FILE)) This specifies a list of include patterns
from a file.
If em(FILE) is "-" the list will be read from standard input.

dit(bf(--files-from=FILE)) Using this option allows you to specify the
exact list of files to transfer (as read from the specified FILE or "-"
for standard input).  It also tweaks the default behavior of rsync to make
transferring just the specified files and directories easier.  For
instance, the --relative option is enabled by default when this option
is used (use --no-relative if you want to turn that off), all
directories specified in the list are created on the destination (rather
than being noisily skipped without -r), and the -a (--archive) option's
behavior does not imply -r (--recursive) -- specify it explicitly, if
you want it.

The file names that are read from the FILE are all relative to the
source dir -- any leading slashes are removed and no ".." references are
allowed to go higher than the source dir.  For example, take this
command:

quote(rsync -a --files-from=/tmp/foo /usr remote:/backup)

If /tmp/foo contains the string "bin" (or even "/bin"), the /usr/bin
directory will be created as /backup/bin on the remote host (but the
contents of the /usr/bin dir would not be sent unless you specified -r
or the names were explicitly listed in /tmp/foo).  Also keep in mind
that the effect of the (enabled by default) --relative option is to
duplicate only the path info that is read from the file -- it does not
force the duplication of the source-spec path (/usr in this case).

In addition, the --files-from file can be read from the remote host
instead of the local host if you specify a "host:" in front of the file
(the host must match one end of the transfer).  As a short-cut, you can
specify just a prefix of ":" to mean "use the remote end of the
transfer".  For example:

quote(rsync -a --files-from=:/path/file-list src:/ /tmp/copy)

This would copy all the files specified in the /path/file-list file that
was located on the remote "src" host.

dit(bf(-0, --from0)) This tells rsync that the filenames it reads from a
file are terminated by a null ('\0') character, not a NL, CR, or CR+LF.
This affects --exclude-from, --include-from, and --files-from.
It does not affect --cvs-exclude (since all names read from a .cvsignore
file are split on whitespace).

dit(bf(-T, --temp-dir=DIR)) This option instructs rsync to use DIR as a
scratch directory when creating temporary copies of the files
transferred on the receiving side.  The default behavior is to create
the temporary files in the receiving directory.

dit(bf(--compare-dest=DIR)) This option instructs rsync to use em(DIR) on
the destination machine as an additional hierarchy to compare destination
files against doing transfers (if the files are missing in the destination
directory).  If a file is found in em(DIR) that is identical to the
sender's file, the file will NOT be transferred to the destination
directory.  This is useful for creating a sparse backup of just files that
have changed from an earlier backup.

Beginning in version 2.6.4, multiple --compare-dest directories may be
provided and rsync will search the list in the order specified until it
finds an existing file.  That first discovery is used as the basis file,
and also determines if the transfer needs to happen.

If em(DIR) is a relative path, it is relative to the destination directory.
See also --copy-dest and --link-dest.

dit(bf(--copy-dest=DIR)) This option behaves like bf(--compare-dest), but
rsync will also copy unchanged files found in em(DIR) to the destination
directory (using the data in the em(DIR) for an efficient copy).  This is
useful for doing transfers to a new destination while leaving existing
files intact, and then doing a flash-cutover when all files have been
successfully transferred.

If em(DIR) is a relative path, it is relative to the destination directory.
See also --compare-dest and --link-dest.

dit(bf(--link-dest=DIR)) This option behaves like bf(--copy-dest), but
unchanged files are hard linked from em(DIR) to the destination directory.
The files must be identical in all preserved attributes (e.g. permissions,
possibly ownership) in order for the files to be linked together.
An example:

verb(
    rsync -av --link-dest=$PWD/prior_dir host:src_dir/ new_dir/
)

Beginning with version 2.6.4, if more than one --link-dest option is
specified, rsync will try to find an exact match to link with (searching
the list in the order specified), and if not found, a basis file from one
of the em(DIR)s will be selected to try to speed up the transfer.

If em(DIR) is a relative path, it is relative to the destination directory.
See also --compare-dest and --copy-dest.

Note that rsync versions prior to 2.6.1 had a bug that could prevent
--link-dest from working properly for a non-root user when -o was specified
(or implied by -a).  If the receiving rsync is not new enough, you can work
around this bug by avoiding the -o option.

dit(bf(-z, --compress)) With this option, rsync compresses any data from
the files that it sends to the destination machine.  This
option is useful on slow connections.  The compression method used is the
same method that gzip uses.

Note this this option typically achieves better compression ratios
that can be achieved by using a compressing remote shell, or a
compressing transport, as it takes advantage of the implicit
information sent for matching data blocks.

dit(bf(--numeric-ids)) With this option rsync will transfer numeric group
and user IDs rather than using user and group names and mapping them
at both ends.

By default rsync will use the username and groupname to determine
what ownership to give files. The special uid 0 and the special group
0 are never mapped via user/group names even if the --numeric-ids
option is not specified.

If a user or group has no name on the source system or it has no match
on the destination system, then the numeric ID
from the source system is used instead.  See also the comments on the
"use chroot" setting in the rsyncd.conf manpage for information on how
the chroot setting affects rsync's ability to look up the names of the
users and groups and what you can do about it.

dit(bf(--timeout=TIMEOUT)) This option allows you to set a maximum I/O
timeout in seconds. If no data is transferred for the specified time
then rsync will exit. The default is 0, which means no timeout.

dit(bf(--blocking-io)) This tells rsync to use blocking I/O when launching
a remote shell transport.  If the remote shell is either rsh or remsh,
rsync defaults to using
blocking I/O, otherwise it defaults to using non-blocking I/O.  (Note that
ssh prefers non-blocking I/O.)

dit(bf(--no-blocking-io)) Turn off --blocking-io, for use when it is the
default.

dit(bf(--log-format=FORMAT)) This allows you to specify exactly what the
rsync client logs to stdout on a per-file basis. The log format is
specified using the same format conventions as the log format option in
rsyncd.conf.

dit(bf(--stats)) This tells rsync to print a verbose set of statistics
on the file transfer, allowing you to tell how effective the rsync
algorithm is for your data.

dit(bf(--partial)) By default, rsync will delete any partially
transferred file if the transfer is interrupted. In some circumstances
it is more desirable to keep partially transferred files. Using the
--partial option tells rsync to keep the partial file which should
make a subsequent transfer of the rest of the file much faster.

dit(bf(--partial-dir=DIR)) Turns on --partial mode, but tells rsync to
put a partially transferred file into em(DIR) instead of writing out the
file to the destination dir.  Rsync will also use a file found in this
dir as data to speed up the transfer (i.e. when you redo the send after
rsync creates a partial file) and delete such a file after it has served
its purpose.  Note that if --whole-file is specified (or implied) that an
existing partial-dir file will not be used to speedup the transfer (since
rsync is sending files without using the incremental rsync algorithm).

Rsync will create the dir if it is missing (just the last dir -- not the
whole path).  This makes it easy to use a relative path (such as
"--partial-dir=.rsync-partial") to have rsync create the partial-directory
in the destination file's directory (rsync will also try to remove the em(DIR)
if a partial file was found to exist at the start of the transfer and the
DIR was specified as a relative path).

If the partial-dir value is not an absolute path, rsync will also add an
--exclude of this value at the end of all your existing excludes.  This
will prevent partial-dir files from being transferred and also prevent the
untimely deletion of partial-dir items on the receiving side.  An example:
the above --partial-dir option would add an "--exclude=.rsync-partial/"
rule at the end of any other include/exclude rules.  Note that if you are
supplying your own include/exclude rules, you may need to manually insert a
rule for this directory exclusion somewhere higher up in the list so that
it has a high enough priority to be effective (e.g., if your rules specify
a trailing --exclude=* rule, the auto-added rule will be ineffective).

IMPORTANT: the --partial-dir should not be writable by other users or it
is a security risk.  E.g. AVOID "/tmp".

You can also set the partial-dir value the RSYNC_PARTIAL_DIR environment
variable.  Setting this in the environment does not force --partial to be
enabled, but rather it effects where partial files go when --partial (or
-P) is used.  For instance, instead of specifying --partial-dir=.rsync-tmp
along with --progress, you could set RSYNC_PARTIAL_DIR=.rsync-tmp in your
environment and then just use the -P option to turn on the use of the
.rsync-tmp dir for partial transfers.  The only time the --partial option
does not look for this environment value is when --inplace was also
specified (since --inplace conflicts with --partial-dir).

dit(bf(--progress)) This option tells rsync to print information
showing the progress of the transfer. This gives a bored user
something to watch.
Implies --verbose without incrementing verbosity.

When the file is transferring, the data looks like this:

verb(
      782448  63%  110.64kB/s    0:00:04
)

This tells you the current file size, the percentage of the transfer that
is complete, the current calculated file-completion rate (including both
data over the wire and data being matched locally), and the estimated time
remaining in this transfer.

After a file is complete, the data looks like this:

verb(
     1238099 100%  146.38kB/s    0:00:08  (5, 57.1% of 396)
)

This tells you the final file size, that it's 100% complete, the final
transfer rate for the file, the amount of elapsed time it took to transfer
the file, and the addition of a total-transfer summary in parentheses.
These additional numbers tell you how many files have been updated, and
what percent of the total number of files has been scanned.

dit(bf(-P)) The -P option is equivalent to --partial --progress.  Its
purpose is to make it much easier to specify these two options for a long
transfer that may be interrupted.

dit(bf(--password-file)) This option allows you to provide a password
in a file for accessing a remote rsync server. Note that this option
is only useful when accessing an rsync server using the built in
transport, not when using a remote shell as the transport. The file
must not be world readable. It should contain just the password as a
single line.

dit(bf(--bwlimit=KBPS)) This option allows you to specify a maximum
transfer rate in kilobytes per second. This option is most effective when
using rsync with large files (several megabytes and up). Due to the nature
of rsync transfers, blocks of data are sent, then if rsync determines the
transfer was too fast, it will wait before sending the next data block. The
result is an average transfer rate equaling the specified limit. A value
of zero specifies no limit.

dit(bf(--write-batch=FILE)) Record a file that can later be applied to
another identical destination with --read-batch. See the "BATCH MODE"
section for details.

dit(bf(--read-batch=FILE)) Apply all of the changes stored in FILE, a
file previously generated by --write-batch.
If em(FILE) is "-" the batch data will be read from standard input.
See the "BATCH MODE" section for details.

dit(bf(-4, --ipv4) or bf(-6, --ipv6)) Tells rsync to prefer IPv4/IPv6
when creating sockets.  This only affects sockets that rsync has direct
control over, such as the outgoing socket when directly contacting an
rsync daemon (see also these options in the --daemon mode section).

dit(bf(--checksum-seed=NUM)) Set the MD4 checksum seed to the integer
NUM.  This 4 byte checksum seed is included in each block and file
MD4 checksum calculation.  By default the checksum seed is generated
by the server and defaults to the current time().  This option
is used to set a specific checksum seed, which is useful for
applications that want repeatable block and file checksums, or
in the case where the user wants a more random checksum seed.
Note that setting NUM to 0 causes rsync to use the default of time()
for checksum seed.

enddit()

The options allowed when starting an rsync daemon are as follows:

startdit()

dit(bf(--daemon)) This tells rsync that it is to run as a daemon.  The
daemon may be accessed using the bf(host::module) or
bf(rsync://host/module/) syntax.

If standard input is a socket then rsync will assume that it is being
run via inetd, otherwise it will detach from the current terminal and
become a background daemon.  The daemon will read the config file
(rsyncd.conf) on each connect made by a client and respond to
requests accordingly.  See the rsyncd.conf(5) man page for more
details.

dit(bf(--address)) By default rsync will bind to the wildcard address
when run as a daemon with the --daemon option or when connecting to a
rsync server. The --address option allows you to specify a specific IP
address (or hostname) to bind to. This makes virtual hosting possible
in conjunction with the --config option.

dit(bf(--bwlimit=KBPS)) This option allows you to specify a maximum
transfer rate in kilobytes per second for the data the daemon sends.
The client can still specify a smaller --bwlimit value, but their
requested value will be rounded down if they try to exceed it.  See the
client version of this option (above) for some extra details.

dit(bf(--config=FILE)) This specifies an alternate config file than
the default.  This is only relevant when --daemon is specified. 
The default is /etc/rsyncd.conf unless the daemon is running over
a remote shell program and the remote user is not root; in that case
the default is rsyncd.conf in the current directory (typically $HOME).

dit(bf(--no-detach)) When running as a daemon, this option instructs
rsync to not detach itself and become a background process.  This
option is required when running as a service on Cygwin, and may also
be useful when rsync is supervised by a program such as
bf(daemontools) or AIX's bf(System Resource Controller).
bf(--no-detach) is also recommended when rsync is run under a
debugger.  This option has no effect if rsync is run from inetd or
sshd.

dit(bf(--port=PORT)) This specifies an alternate TCP port number to use
rather than the default port 873.

dit(bf(-4, --ipv4) or bf(-6, --ipv6)) Tells rsync to prefer IPv4/IPv6
when creating the incoming sockets that the rsync daemon will use to
listen for connections.  One of these options may be required in older
versions of Linux to work around an IPv6 bug in the kernel (if you see
an "address already in use" error when nothing else is using the port,
try specifying --ipv6 or --ipv4 when starting the daemon).

dit(bf(-h, --help)) When specified after --daemon, print a short help
page describing the options available for starting an rsync daemon.

enddit()

manpagesection(EXCLUDE PATTERNS)

The exclude and include patterns specified to rsync allow for flexible
selection of which files to transfer and which files to skip.

Rsync builds an ordered list of include/exclude options as specified on
the command line. Rsync checks each file and directory 
name against each exclude/include pattern in turn. The first matching
pattern is acted on. If it is an exclude pattern, then that file is
skipped. If it is an include pattern then that filename is not
skipped. If no matching include/exclude pattern is found then the
filename is not skipped.

The filenames matched against the exclude/include patterns are relative
to the "root of the transfer".  If you think of the transfer as a
subtree of names that are being sent from sender to receiver, the root
is where the tree starts to be duplicated in the destination directory.
This root governs where patterns that start with a / match (see below).

Because the matching is relative to the transfer-root, changing the
trailing slash on a source path or changing your use of the --relative
option affects the path you need to use in your matching (in addition to
changing how much of the file tree is duplicated on the destination
system).  The following examples demonstrate this.

Let's say that we want to match two source files, one with an absolute
path of "/home/me/foo/bar", and one with a path of "/home/you/bar/baz".
Here is how the various command choices differ for a 2-source transfer:

verb(
   Example cmd: rsync -a /home/me /home/you /dest
   +/- pattern: /me/foo/bar
   +/- pattern: /you/bar/baz
   Target file: /dest/me/foo/bar
   Target file: /dest/you/bar/baz

   Example cmd: rsync -a /home/me/ /home/you/ /dest
   +/- pattern: /foo/bar               (note missing "me")
   +/- pattern: /bar/baz               (note missing "you")
   Target file: /dest/foo/bar
   Target file: /dest/bar/baz

   Example cmd: rsync -a --relative /home/me/ /home/you /dest
   +/- pattern: /home/me/foo/bar       (note full path)
   +/- pattern: /home/you/bar/baz      (ditto)
   Target file: /dest/home/me/foo/bar
   Target file: /dest/home/you/bar/baz

   Example cmd: cd /home; rsync -a --relative me/foo you/ /dest
   +/- pattern: /me/foo/bar      (starts at specified path)
   +/- pattern: /you/bar/baz     (ditto)
   Target file: /dest/me/foo/bar
   Target file: /dest/you/bar/baz
)

The easiest way to see what name you should include/exclude is to just
look at the output when using --verbose and put a / in front of the name
(use the --dry-run option if you're not yet ready to copy any files).

Note that, when using the --recursive (-r) option (which is implied by -a),
every subcomponent of
every path is visited from the top down, so include/exclude patterns get
applied recursively to each subcomponent.
The exclude patterns actually short-circuit the directory traversal stage
when rsync finds the files to send.  If a pattern excludes a particular
parent directory, it can render a deeper include pattern ineffectual
because rsync did not descend through that excluded section of the
hierarchy.

Note also that the --include and --exclude options take one pattern
each. To add multiple patterns use the --include-from and
--exclude-from options or multiple --include and --exclude options. 

The patterns can take several forms. The rules are:

itemize(

  it() if the pattern starts with a / then it is matched against the
  start of the filename, otherwise it is matched against the end of
  the filename.
  This is the equivalent of a leading ^ in regular expressions.
  Thus "/foo" would match a file called "foo" at the transfer-root
  (see above for how this is different from the filesystem-root).
  On the other hand, "foo" would match any file called "foo"
  anywhere in the tree because the algorithm is applied recursively from
  top down; it behaves as if each path component gets a turn at being the
  end of the file name.

  it() if the pattern ends with a / then it will only match a
  directory, not a file, link, or device.

  it() if the pattern contains a wildcard character from the set
  *?[ then expression matching is applied using the shell filename
  matching rules. Otherwise a simple string match is used.

  it() the double asterisk pattern "**" will match slashes while a
  single asterisk pattern "*" will stop at slashes.

  it() if the pattern contains a / (not counting a trailing /) or a "**"
  then it is matched against the full filename, including any leading
  directory. If the pattern doesn't contain a / or a "**", then it is
  matched only against the final component of the filename.  Again,
  remember that the algorithm is applied recursively so "full filename" can
  actually be any portion of a path below the starting directory.

  it() if the pattern starts with "+ " (a plus followed by a space)
  then it is always considered an include pattern, even if specified as
  part of an exclude option. The prefix is discarded before matching.

  it() if the pattern starts with "- " (a minus followed by a space)
  then it is always considered an exclude pattern, even if specified as
  part of an include option. The prefix is discarded before matching.

  it() if the pattern is a single exclamation mark ! then the current
  include/exclude list is reset, removing all previously defined patterns.
)

The +/- rules are most useful in a list that was read from a file, allowing
you to have a single exclude list that contains both include and exclude
options in the proper order.

Remember that the matching occurs at every step in the traversal of the
directory hierarchy, so you must be sure that all the parent directories of
the files you want to include are not excluded.  This is particularly
important when using a trailing '*' rule.  For instance, this won't work:

verb(
    + /some/path/this-file-will-not-be-found
    + /file-is-included
    - *
)

This fails because the parent directory "some" is excluded by the '*' rule,
so rsync never visits any of the files in the "some" or "some/path"
directories.  One solution is to ask for all directories in the hierarchy
to be included by using a single rule: --include='*/' (put it somewhere
before the --exclude='*' rule).  Another solution is to add specific
include rules for all the parent dirs that need to be visited.  For
instance, this set of rules works fine:

verb(
    + /some/
    + /some/path/
    + /some/path/this-file-is-found
    + /file-also-included
    - *
)

Here are some examples of exclude/include matching:

itemize(
  it() --exclude "*.o" would exclude all filenames matching *.o
  it() --exclude "/foo" would exclude a file called foo in the transfer-root directory
  it() --exclude "foo/" would exclude any directory called foo
  it() --exclude "/foo/*/bar" would exclude any file called bar two
  levels below a directory called foo in the transfer-root directory
  it() --exclude "/foo/**/bar" would exclude any file called bar two
  or more levels below a directory called foo in the transfer-root directory
  it() --include "*/" --include "*.c" --exclude "*" would include all 
  directories and C source files
  it() --include "foo/" --include "foo/bar.c" --exclude "*" would include
  only foo/bar.c (the foo/ directory must be explicitly included or
  it would be excluded by the "*")
)

manpagesection(BATCH MODE)

bf(Note:) Batch mode should be considered experimental in this version
of rsync. The interface and behavior have now stabilized, though, so
feel free to try this out.

Batch mode can be used to apply the same set of updates to many
identical systems. Suppose one has a tree which is replicated on a
number of hosts.  Now suppose some changes have been made to this
source tree and those changes need to be propagated to the other
hosts. In order to do this using batch mode, rsync is run with the
write-batch option to apply the changes made to the source tree to one
of the destination trees.  The write-batch option causes the rsync
client to store in a "batch file" all the information needed to repeat
this operation against other, identical destination trees.

To apply the recorded changes to another destination tree, run rsync
with the read-batch option, specifying the name of the same batch
file, and the destination tree.  Rsync updates the destination tree
using the information stored in the batch file.

For convenience, one additional file is creating when the write-batch
option is used.  This file's name is created by appending
".sh" to the batch filename.  The .sh file contains
a command-line suitable for updating a destination tree using that
batch file. It can be executed using a Bourne(-like) shell, optionally
passing in an alternate destination tree pathname which is then used
instead of the original path. This is useful when the destination tree
path differs from the original destination tree path.

Generating the batch file once saves having to perform the file
status, checksum, and data block generation more than once when
updating multiple destination trees. Multicast transport protocols can
be used to transfer the batch update files in parallel to many hosts
at once, instead of sending the same data to every host individually.

Examples:

verb(
   $ rsync --write-batch=foo -a host:/source/dir/ /adest/dir/
   $ scp foo* remote:
   $ ssh remote ./foo.sh /bdest/dir/
)

verb(
   $ rsync --write-batch=foo -a /source/dir/ /adest/dir/
   $ ssh remote rsync --read-batch=- -a /bdest/dir/ <foo
)

In these examples, rsync is used to update /adest/dir/ from /source/dir/
and the information to repeat this operation is stored in "foo" and
"foo.sh".  The host "remote" is then updated with the batched data going
into the directory /bdest/dir.  The differences between the two examples
reveals some of the flexibility you have in how you deal with batches:

itemize(

  it() The first example shows that the initial copy doesn't have to be
  local -- you can push or pull data to/from a remote host using either the
  remote-shell syntax or rsync daemon syntax, as desired.

  it() The first example uses the created "foo.sh" file to get the right
  rsync options when running the read-batch command on the remote host.

  it() The second example reads the batch data via standard input so that
  the batch file doesn't need to be copied to the remote machine first.
  This example avoids the foo.sh script because it needed to use a modified
  --read-batch option, but you could edit the script file if you wished to
  make use of it (just be sure that no other option is trying to use
  standard input, such as the "--exclude-from=-" option).

)

Caveats:

The read-batch option expects the destination tree that it is updating
to be identical to the destination tree that was used to create the
batch update fileset.  When a difference between the destination trees
is encountered the update might be discarded with no error (if the file
appears to be up-to-date already) or the file-update may be attempted
and then, if the file fails to verify, the update discarded with an
error.  This means that it should be safe to re-run a read-batch operation
if the command got interrupted.  If you wish to force the batched-update to
always be attempted regardless of the file's size and date, use the -I
option (when reading the batch).
If an error occurs, the destination tree will probably be in a
partially updated state. In that case, rsync can
be used in its regular (non-batch) mode of operation to fix up the
destination tree.

The rsync version used on all destinations must be at least as new as the
one used to generate the batch file.  Rsync will die with an error if the
protocol version in the batch file is too new for the batch-reading rsync
to handle.

The --dry-run (-n) option does not work in batch mode and yields a runtime
error.

When reading a batch file, rsync will force the value of certain options
to match the data in the batch file if you didn't set them to the same
as the batch-writing command.  Other options can (and should) be changed.
For instance
--write-batch changes to --read-batch, --files-from is dropped, and the
--include/--exclude options are not needed unless --delete is specified
without --delete-excluded.

The code that creates the BATCH.sh file transforms any include/exclude
options into a single list that is appended as a "here" document to the
shell script file.  An advanced user can use this to modify the exclude
list if a change in what gets deleted by --delete is desired.  A normal
user can ignore this detail and just use the shell script as an easy way
to run the appropriate --read-batch command for the batched data.

The original batch mode in rsync was based on "rsync+", but the latest
version uses a new implementation.

manpagesection(SYMBOLIC LINKS)

Three basic behaviors are possible when rsync encounters a symbolic
link in the source directory.

By default, symbolic links are not transferred at all.  A message
"skipping non-regular" file is emitted for any symlinks that exist.

If bf(--links) is specified, then symlinks are recreated with the same
target on the destination.  Note that bf(--archive) implies
bf(--links).

If bf(--copy-links) is specified, then symlinks are "collapsed" by
copying their referent, rather than the symlink.

rsync also distinguishes "safe" and "unsafe" symbolic links.  An
example where this might be used is a web site mirror that wishes
ensure the rsync module they copy does not include symbolic links to
bf(/etc/passwd) in the public section of the site.  Using
bf(--copy-unsafe-links) will cause any links to be copied as the file
they point to on the destination.  Using bf(--safe-links) will cause
unsafe links to be omitted altogether.

Symbolic links are considered unsafe if they are absolute symlinks
(start with bf(/)), empty, or if they contain enough bf("..")
components to ascend from the directory being copied.

manpagesection(DIAGNOSTICS)

rsync occasionally produces error messages that may seem a little
cryptic. The one that seems to cause the most confusion is "protocol
version mismatch - is your shell clean?".

This message is usually caused by your startup scripts or remote shell
facility producing unwanted garbage on the stream that rsync is using
for its transport. The way to diagnose this problem is to run your
remote shell like this:

verb(
   ssh remotehost /bin/true > out.dat
)
       
then look at out.dat. If everything is working correctly then out.dat
should be a zero length file. If you are getting the above error from
rsync then you will probably find that out.dat contains some text or
data. Look at the contents and try to work out what is producing
it. The most common cause is incorrectly configured shell startup
scripts (such as .cshrc or .profile) that contain output statements
for non-interactive logins.

If you are having trouble debugging include and exclude patterns, then
try specifying the -vv option.  At this level of verbosity rsync will
show why each individual file is included or excluded.

manpagesection(EXIT VALUES)

startdit()
dit(bf(0)) Success
dit(bf(1)) Syntax or usage error 
dit(bf(2)) Protocol incompatibility 
dit(bf(3)) Errors selecting input/output files, dirs
dit(bf(4)) Requested action not supported: an attempt
was made to manipulate 64-bit files on a platform that cannot support
them; or an option was specified that is supported by the client and
not by the server.
dit(bf(5)) Error starting client-server protocol
dit(bf(10)) Error in socket I/O 
dit(bf(11)) Error in file I/O 
dit(bf(12)) Error in rsync protocol data stream 
dit(bf(13)) Errors with program diagnostics 
dit(bf(14)) Error in IPC code 
dit(bf(20)) Received SIGUSR1 or SIGINT 
dit(bf(21)) Some error returned by waitpid() 
dit(bf(22)) Error allocating core memory buffers 
dit(bf(23)) Partial transfer due to error
dit(bf(24)) Partial transfer due to vanished source files
dit(bf(30)) Timeout in data send/receive 
enddit()

manpagesection(ENVIRONMENT VARIABLES)

startdit()

dit(bf(CVSIGNORE)) The CVSIGNORE environment variable supplements any
ignore patterns in .cvsignore files. See the --cvs-exclude option for
more details.

dit(bf(RSYNC_RSH)) The RSYNC_RSH environment variable allows you to
override the default shell used as the transport for rsync.  Command line
options are permitted after the command name, just as in the -e option.

dit(bf(RSYNC_PROXY)) The RSYNC_PROXY environment variable allows you to
redirect your rsync client to use a web proxy when connecting to a
rsync daemon. You should set RSYNC_PROXY to a hostname:port pair.

dit(bf(RSYNC_PASSWORD)) Setting RSYNC_PASSWORD to the required
password allows you to run authenticated rsync connections to an rsync
daemon without user intervention. Note that this does not supply a
password to a shell transport such as ssh.

dit(bf(USER) or bf(LOGNAME)) The USER or LOGNAME environment variables
are used to determine the default username sent to an rsync server.
If neither is set, the username defaults to "nobody".

dit(bf(HOME)) The HOME environment variable is used to find the user's
default .cvsignore file.

enddit()

manpagefiles()

/etc/rsyncd.conf or rsyncd.conf

manpageseealso()

rsyncd.conf(5)

manpagediagnostics()

manpagebugs()

times are transferred as unix time_t values

When transferring to FAT filesystems rsync may re-sync
unmodified files.
See the comments on the --modify-window option.

file permissions, devices, etc. are transferred as native numerical
values

see also the comments on the --delete option

Please report bugs! See the website at
url(http://rsync.samba.org/)(http://rsync.samba.org/)

manpagesection(CREDITS)

rsync is distributed under the GNU public license.  See the file
COPYING for details.

A WEB site is available at
url(http://rsync.samba.org/)(http://rsync.samba.org/).  The site
includes an FAQ-O-Matic which may cover questions unanswered by this
manual page.

The primary ftp site for rsync is
url(ftp://rsync.samba.org/pub/rsync)(ftp://rsync.samba.org/pub/rsync).

We would be delighted to hear from you if you like this program.

This program uses the excellent zlib compression library written by
Jean-loup Gailly and Mark Adler.

manpagesection(THANKS)

Thanks to Richard Brent, Brendan Mackay, Bill Waite, Stephen Rothwell
and David Bell for helpful suggestions, patches and testing of rsync.
I've probably missed some people, my apologies if I have.

Especial thanks also to: David Dykstra, Jos Backus, Sebastian Krahmer,
Martin Pool, Wayne Davison, J.W. Schultz.

manpageauthor()

rsync was originally written by Andrew Tridgell and Paul Mackerras.
Many people have later contributed to it.

Mailing lists for support and development are available at
url(http://lists.samba.org)(lists.samba.org)