rsync Linux Service

rsync service:

Remote Synchronization. A server to enable remote synchronization of files in a specified directory tree.
Now lets see the manual of rsync service.
Manual rsync:
NAME
rsync - faster, flexible replacement for rcp
SYNOPSIS
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
DESCRIPTION
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:
support for copying links, devices, owners, groups, and permissions
exclude and exclude-from options similar to GNU tar
a CVS exclude mode for ignoring the same files that CVS would ignore
can use any transparent remote shell, including ssh or rsh
does not require root privileges
pipelining of file transfers to minimize latency costs
support for anonymous or authenticated rsync servers (ideal for mirroring)
GENERAL
There are eight different ways of using rsync. They are:
for copying local files. This is invoked when neither source nor destination path contains a : separator
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.
for copying from a remote machine to the local machine using a remote shell program. This is invoked when the source contains a : separator.
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.
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.
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.
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.
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.
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.
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:
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.
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.
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:
rsync -av /src/foo /dest
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.
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.)
ADVANCED USAGE
The syntax for requesting multiple files from a remote host involves using quoted spaces in the SRC. Some examples:
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.
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:
rsync -av host:'file name with spaces' /dest
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.
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:
you use a double colon :: instead of a single colon to separate the hostname from the path or an rsync:// URL.
the remote server may print a message of the day when you connect.
if you specify no path name on the remote server then the list of accessible paths on the server will be shown.
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.
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:
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.
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).
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.
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
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:
get:
rsync -avuzb --exclude '*~' samba:samba/ .
put:
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
rsync -az -e ssh --delete ~ftp/pub/samba/ nimbus:"~ftp/pub/tridge/samba"
this is launched from cron every few hours.
OPTIONS SUMMARY
Here is a short summary of the options available in rsync. Please refer to the detailed description below for a complete description.
OPTIONS
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.
-h, --help
Print a short help page describing the options available in rsync
--version
print the rsync version number and exit
-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.
-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.
-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.
--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.
--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.
-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.
-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 -a does not preserve hardlinks, because finding multiply-linked files is expensive. You must separately specify -H.
-r, --recursive
This tells rsync to copy directories recursively. If you don't specify this then rsync won't copy directories at all.
-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
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
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.
--no-relative
Turn off the --relative option. This is only needed if you want to use --files-from without its implied --relative file processing.
--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.
-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.
--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).
--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.
-u, --update
This forces rsync to skip any files for which the destination file already exists and has a date later than the source file.
In the currently implementation, a difference of file format 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).
-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.
--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, and --link-dest (a future rsync version will hopefully update the protocol to remove 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.
-l, --links
When symlinks are encountered, recreate the symlink on the destination.
-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.
--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.
--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.
-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.
-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.
--no-whole-file
Turn off --whole-file, for use when it is the default.
-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).
-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.
-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.
-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.
-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).
-n, --dry-run
This tells rsync to not do any file transfers, instead it will just report the actions it would have taken.
-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.
-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.
--existing
This tells rsync not to create any new files - only update files that already exist on the destination.
--ignore-existing
This tells rsync not to update files that already exist on the destination.
--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.
--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.
--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.
--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.
--ignore-errors
Tells --delete to go ahead and delete files even when there are I/O errors.
--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.
-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.
-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 [user@]host::module/path, then the remote shell 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:
-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.
--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.
-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:
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 //.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 cvs(1) manual for more information.
--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.
--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 FILE is - the list will be read from standard input.
--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.
--include-from=FILE
This specifies a list of include patterns from a file. If FILE is "-" the list will be read from standard input.
--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:
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:
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.
-0, --from0
This tells rsync that the filenames it reads from a file are terminated by a null ('?') 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).
-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.
--compare-dest=DIR
This option instructs rsync to use DIR on the destination machine as an additional directory to compare destination files against when doing transfers if the files are missing in the destination directory. This is useful for doing transfers to a new destination while leaving existing files intact, and then doing a flashcutover when all files have been successfully transferred (for example by moving directories around and removing the old directory, although this skips files that haven't changed; see also --link-dest). This option increases the usefulness of --partial because partially transferred files will remain in the new temporary destination until they have a chance to be completed. If DIR is a relative path, it is relative to the destination directory.
--link-dest=DIR
This option behaves like --compare-dest but also will create hard links from DIR to the destination directory for unchanged files. Files with changed ownership or permissions will not be linked. An example:
rsync -av --link-dest=//prior_dir host:src_dir/ new_dir/
Like --compare-dest if DIR is a relative path, it is relative to the destination directory. 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.
-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.
--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.
--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.
--daemon
This tells rsync that it is to run as a daemon. The daemon may be accessed using the host::module or 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.
--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 daemontools or AIX's System Resource Controller. --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.
--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.
--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 /).
--port=PORT
This specifies an alternate TCP port number to use rather than the default port 873.
--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.)
--no-blocking-io
Turn off --blocking-io, for use when it is the default.
--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.
--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.
--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.
--partial-dir=DIR
Turns on --partial mode, but tells rsync to put a partially transferred file into 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 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).
--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:
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 the a file is complete, it the data looks like this:
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.
-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.
--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.
--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.
--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.
--read-batch=FILE
Apply all of the changes stored in FILE, a file previously generated by --write-batch. If FILE is "-" the batch data will be read from standard input. See the "BATCH MODE" section for details.
-4, --ipv4 or -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, or the incoming sockets that an rsync daemon uses 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).
--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.
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:
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:
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.
if the pattern ends with a / then it will only match a directory, not a file, link, or device.
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.
the double asterisk pattern "**" will match slashes while a single asterisk pattern "*" will stop at slashes.
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.
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.
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.
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:
+ /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:
+ /some/
+ /some/path/
+ /some/path/this-file-is-found
+ /file-also-included
- *
Here are some examples of exclude/include matching:
--exclude "*.o" would exclude all filenames matching *.o
--exclude "/foo" would exclude a file called foo in the transfer-root directory
--exclude "foo/" would exclude any directory called foo
--exclude "/foo/*/bar" would exclude any file called bar two levels below a directory called foo in the transfer-root directory
--exclude "/foo/**/bar" would exclude any file called bar two or more levels below a directory called foo in the transfer-root directory
--include "*/" --include "*.c" --exclude "*" would include all directories and C source files
--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 "*")
BATCH MODE
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:
$ rsync --write-batch=foo -a host:/source/dir/ /adest/dir/
$ scp foo* remote:
$ ssh remote ./foo.sh /bdest/dir/
$ 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:
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.
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.
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.
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 --links is specified, then symlinks are recreated with the same target on the destination. Note that --archive implies --links.
If --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 /etc/passwd in the public section of the site. Using --copy-unsafe-links will cause any links to be copied as the file they point to on the destination. Using --safe-links will cause unsafe links to be omitted altogether.
Symbolic links are considered unsafe if they are absolute symlinks (start with /), empty, or if they contain enough \"..\" components to ascend from the directory being copied.
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:
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.
EXIT VALUES
0 Success
1 Syntax or usage error
2 Protocol incompatibility
3 Errors selecting input/output files, dirs
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.
5 Error starting client-server protocol
10 Error in socket I/O
11 Error in file I/O
12 Error in rsync protocol data stream
13 Errors with program diagnostics
14 Error in IPC code
20 Received SIGUSR1 or SIGINT
21 Some error returned by waitpid()
22 Error allocating core memory buffers
23 Partial transfer due to error
24 Partial transfer due to vanished source files
30 Timeout in data send/receive
ENVIRONMENT VARIABLES
CVSIGNORE
The CVSIGNORE environment variable supplements any ignore patterns in .cvsignore files. See the --cvs- exclude option for more details.
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.
RSYNC_PROXY
The RSYNC_PROXY environment variable allows you to redirect your rsync client to use a web proxy when con- necting to a rsync daemon. You should set RSYNC_PROXY to a hostname:port pair.
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.
USER or 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\".
HOME The HOME environment variable is used to find the user's default .cvsignore file.
FILES
/etc/rsyncd.conf or rsyncd.conf
SEE ALSO
rsyncd.conf(5)
DIAGNOSTICS
BUGS
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 http://rsync.samba.org/
CREDITS
rsync is distributed under the GNU public license. See the file COPYING for details.
A WEB site is available at 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 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.
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.
AUTHOR
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 http://lists.samba.org