rsync - phpMan

rsync(1) rsync(1)

NAME
rsync - a fast, versatile, remote (and local) file-copying tool

SYNOPSIS
Local: rsync [OPTION...] SRC... [DEST]

Access via remote shell:
Pull: rsync [OPTION...] [USER@]HOST:SRC... [DEST]
Push: rsync [OPTION...] SRC... [USER@]HOST:DEST

Access via rsync daemon:
Pull: rsync [OPTION...] [USER@]HOST::SRC... [DEST]
rsync [OPTION...] rsync://[USER@]HOST[:PORT]/SRC... [DEST]
Push: rsync [OPTION...] SRC... [USER@]HOST::DEST
rsync [OPTION...] SRC... rsync://[USER@]HOST[:PORT]/DEST

Usages with just one SRC arg and no DEST arg will list the source files instead of copy-
ing.

DESCRIPTION
Rsync is a fast and extraordinarily versatile file copying tool. It can copy locally,
to/from another host over any remote shell, or to/from a remote rsync daemon. It offers a
large number of options that control every aspect of its behavior and permit very flexible
specification of the set of files to be copied. It is famous for its delta-transfer algo-
rithm, which reduces the amount of data sent over the network by sending only the differ-
ences between the source files and the existing files in the destination. Rsync is widely
used for backups and mirroring and as an improved copy command for everyday use.

Rsync finds files that need to be transferred using a "quick check" algorithm (by default)
that looks for files that have changed in size or in last-modified time. Any changes in
the other preserved attributes (as requested by options) are made on the destination file
directly when the quick check indicates that the file's data does not need to be updated.

Some of the additional features of rsync are:

o support for copying links, devices, owners, groups, and permissions

o exclude and exclude-from options similar to GNU tar

o a CVS exclude mode for ignoring the same files that CVS would ignore

o can use any transparent remote shell, including ssh or rsh

o does not require super-user privileges

o pipelining of file transfers to minimize latency costs

o support for anonymous or authenticated rsync daemons (ideal for mirroring)

GENERAL
Rsync copies files either to or from a remote host, or locally on the current host (it
does not support copying files between two remote hosts).

There are two different ways for rsync to contact a remote system: using a remote-shell
program as the transport (such as ssh or rsh) or contacting an rsync daemon directly via
TCP. The remote-shell transport is used whenever the source or destination path contains
a single colon (:) separator after a host specification. Contacting an rsync daemon di-
rectly happens when the source or destination path contains a double colon (::) separator
after a host specification, OR when an rsync:// URL is specified (see also the "USING
RSYNC-DAEMON FEATURES VIA A REMOTE-SHELL CONNECTION" section for an exception to this lat-
ter rule).

As a special case, if a single source arg is specified without a destination, the files
are listed in an output format similar to "ls -l".

As expected, if neither the source or destination path specify a remote host, the copy oc-
curs locally (see also the --list-only option).

Rsync refers to the local side as the "client" and the remote side as the "server". Don't
confuse "server" with an rsync daemon -- a daemon is always a server, but a server can be
either a daemon or a remote-shell spawned process.

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 op-
tion, or by setting the RSYNC_RSH environment variable.

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 dif-
ferences in the data. Note that the expansion of wildcards on the commandline (*.c) into
a list of files is handled by the shell before it runs rsync and not by rsync itself (ex-
actly the same as all other posix-style programs).

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 "ar-
chive" mode, which ensures that symbolic links, devices, attributes, permissions, owner-
ships, etc. are preserved in the transfer. Additionally, compression will be used to re-
duce 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 di-
rectory 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

Note also that host and module references don't require a trailing slash to copy the con-
tents of the default directory. For example, both of these copy the remote directory's
contents into "/dest":

rsync -av host: /dest
rsync -av host::module /dest

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.

Finally, you can list all the (listable) modules available from a particular rsync daemon
by leaving off the module name:

rsync somehost.mydomain.com::

See the following section for more details.

ADVANCED USAGE
The syntax for requesting multiple files from a remote host is done by specifying addi-
tional remote-host args in the same style as the first, or with the hostname omitted. For
instance, all these work:

rsync -av host:file1 :file2 host:file{3,4} /dest/
rsync -av host::modname/file{1,2} host::modname/file3 /dest/
rsync -av host::modname/file1 ::modname/file{3,4} /dest/

Older versions of rsync required using quoted spaces in the SRC, like these examples:

rsync -av host:'dir1/file1 dir2/file2' /dest
rsync host::'modname/dir1/file1 modname/dir2/file2' /dest

Starting this version of rsync, filenames are passed to a remote shell in such a way as to
preserve the characters you give it. Thus, if you ask for a file with spaces in the name,
that's what the remote rsync looks for:

rsync -aiv host:'a simple file.pdf' /dest/

If you use scripts that have been written to manually apply extra quoting to the remote
rsync args (or to require remote arg splitting), you can ask rsync to let your script han-
dle the extra escaping. This is done by either adding the --old-args option to the rsync
runs in the script (which requires a new rsync) or exporting RSYNC_OLD_ARGS=1 and
RSYNC_PROTECT_ARGS=0 (which works with old or new rsync versions).

CONNECTING TO AN RSYNC DAEMON
It is also possible to use rsync without a remote shell as the transport. In this case
you will directly connect to a remote rsync daemon, typically using TCP port 873. (This
obviously requires the daemon to be running on the remote system, so refer to the STARTING
AN RSYNC DAEMON TO ACCEPT CONNECTIONS section below for information on that.)

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

o you either use a double colon :: instead of a single colon to separate the hostname
from the path, or you use an rsync:// URL.

o the first word of the "path" is actually a module name.

o the remote daemon may print a message of the day when you connect.

o if you specify no path name on the remote daemon then the list of accessible paths
on the daemon will be shown.

o if you specify no local destination then a listing of the specified files on the
remote daemon is provided.

o you must not specify the --rsh (-e) option.

An example that copies all the files in a remote module named "src":

rsync -av host::src /dest

Some modules on the remote daemon may require authentication. If so, you will receive a
password prompt when you connect. You can avoid the password prompt by setting the envi-
ronment variable RSYNC_PASSWORD to the password you want to use or using the --pass-
word-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.

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.

You may also establish a daemon connection using a program as a proxy by setting the envi-
ronment variable RSYNC_CONNECT_PROG to the commands you wish to run in place of making a
direct socket connection. The string may contain the escape "%H" to represent the host-
name specified in the rsync command (so use "%%" if you need a single "%" in your string).
For example:

export RSYNC_CONNECT_PROG='ssh proxyhost nc %H 873'
rsync -av targethost1::module/src/ /dest/
rsync -av rsync:://targethost2/module/src/ /dest/

The command specified above uses ssh to run nc (netcat) on a proxyhost, which forwards all
data to port 873 (the rsync daemon) on the targethost (%H).

USING RSYNC-DAEMON FEATURES VIA A REMOTE-SHELL CONNECTION
It is sometimes useful to use various features of an rsync daemon (such as named modules)
without actually allowing any new socket connections into a system (other than what is al-
ready required to allow remote-shell access). Rsync supports connecting to a host using a
remote shell and then spawning a single-use "daemon" server that expects to read its con-
fig file in the home dir of the remote user. This can be useful if you want to encrypt a
daemon-style transfer's data, but since the daemon is started up fresh by the remote user,
you may not be able to use features such as chroot or change the uid used by the daemon.
(For another way to encrypt a daemon transfer, consider using ssh to tunnel a local port
to a remote machine and configure a normal rsync daemon on that remote host to only allow
connections from "localhost".)

From the user's perspective, a daemon transfer via a remote-shell connection uses nearly
the same command-line syntax as a normal rsync-daemon transfer, with the only exception
being that you must explicitly set the remote shell program on the command-line with the
--rsh=COMMAND option. (Setting the RSYNC_RSH in the environment will not turn on this
functionality.) For example:

rsync -av --rsh=ssh host::module /dest

If you need to specify a different remote-shell user, keep in mind that the user@ prefix
in front of the host is specifying the rsync-user value (for a module that requires
user-based authentication). This means that you must give the '-l user' option to ssh
when specifying the remote-shell, as in this example that uses the short version of the
--rsh option:

rsync -av -e "ssh -l ssh-user" rsync-user@host::module /dest

The "ssh-user" will be used at the ssh level; the "rsync-user" will be used to log-in to
the "module".

STARTING AN RSYNC DAEMON TO ACCEPT CONNECTIONS
In order to connect to an rsync daemon, the remote system needs to have a daemon already
running (or it needs to have configured something like inetd to spawn an rsync daemon for
incoming connections on a particular port). For full information on how to start a daemon
that will handling incoming socket connections, see the rsyncd.conf(5) man page -- that is
the config file for the daemon, and it contains the full details for how to run the daemon
(including stand-alone and inetd configurations).

If you're using one of the remote-shell transports for the transfer, there is no need to
manually start an rsync daemon.

SORTED TRANSFER ORDER
Rsync always sorts the specified filenames into its internal transfer list. This handles
the merging together of the contents of identically named directories, makes it easy to
remove duplicate filenames, and may confuse someone when the files are transferred in a
different order than what was given on the command-line.

If you need a particular file to be transferred prior to another, either separate the
files into different rsync calls, or consider using --delay-updates (which doesn't affect
the sorted transfer order, but does make the final file-updating phase happen much more
rapidly).

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 fold-
ers, 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"

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.

-v, --verbose increase verbosity
--info=FLAGS fine-grained informational verbosity
--debug=FLAGS fine-grained debug verbosity
--msgs2stderr special output handling for debugging
-q, --quiet suppress non-error messages
--no-motd suppress daemon-mode MOTD (see caveat)
-c, --checksum skip based on checksum, not mod-time & size
-a, --archive archive mode; equals -rlptgoD (no -H,-A,-X)
--no-OPTION turn off an implied OPTION (e.g. --no-D)
-r, --recursive recurse into directories
-R, --relative use relative path names
--no-implied-dirs don't send implied dirs with --relative
-b, --backup make backups (see --suffix & --backup-dir)
--backup-dir=DIR make backups into hierarchy based in DIR
--suffix=SUFFIX backup suffix (default ~ w/o --backup-dir)
-u, --update skip files that are newer on the receiver
--inplace update destination files in-place
--append append data onto shorter files
--append-verify --append w/old data in file checksum
-d, --dirs transfer directories without recursing
--old-dirs, --old-d works like --dirs when talking to old rsync
-l, --links copy symlinks as symlinks
-L, --copy-links transform symlink into referent file/dir
--copy-unsafe-links only "unsafe" symlinks are transformed
--safe-links ignore symlinks that point outside the tree
--munge-links munge symlinks to make them safer
-k, --copy-dirlinks transform symlink to dir into referent dir
-K, --keep-dirlinks treat symlinked dir on receiver as dir
-H, --hard-links preserve hard links
-p, --perms preserve permissions
-E, --executability preserve executability
--chmod=CHMOD affect file and/or directory permissions
-A, --acls preserve ACLs (implies -p)
-X, --xattrs preserve extended attributes
-o, --owner preserve owner (super-user only)
-g, --group preserve group
--devices preserve device files (super-user only)
--specials preserve special files
-D same as --devices --specials
-t, --times preserve modification times
-O, --omit-dir-times omit directories from --times
-J, --omit-link-times omit symlinks from --times
--super receiver attempts super-user activities
--fake-super store/recover privileged attrs using xattrs
-S, --sparse turn sequences of nulls into sparse blocks
--preallocate allocate dest files before writing
-n, --dry-run perform a trial run with no changes made
-W, --whole-file copy files whole (w/o delta-xfer algorithm)
--checksum-choice=STR choose the checksum algorithms
-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 to use
--rsync-path=PROGRAM specify the rsync to run on remote machine
--existing skip creating new files on receiver
--ignore-existing skip updating files that exist on receiver
--remove-source-files sender removes synchronized files (non-dir)
--del an alias for --delete-during
--delete delete extraneous files from dest dirs
--delete-before receiver deletes before xfer, not during
--delete-during receiver deletes during the transfer
--delete-delay find deletions during, delete after
--delete-after receiver deletes after transfer, not during
--delete-excluded also delete excluded files from dest dirs
--ignore-missing-args ignore missing source args without error
--delete-missing-args delete missing source args from destination
--ignore-errors delete even if there are I/O errors
--force force deletion of dirs even if not empty
--max-delete=NUM don't delete more than NUM files
--max-size=SIZE don't transfer any file larger than SIZE
--min-size=SIZE don't transfer any file smaller than SIZE
--partial keep partially transferred files
--partial-dir=DIR put a partially transferred file into DIR
--delay-updates put all updated files into place at end
-m, --prune-empty-dirs prune empty directory chains from file-list
--numeric-ids don't map uid/gid values by user/group name
--usermap=STRING custom username mapping
--groupmap=STRING custom groupname mapping
--chown=USER:GROUP simple username/groupname mapping
--timeout=SECONDS set I/O timeout in seconds
--contimeout=SECONDS set daemon connection timeout in seconds
-I, --ignore-times don't skip files that match size and time
--size-only skip files that match in size
-@, --modify-window=NUM set the accuracy for mod-time comparisons
-T, --temp-dir=DIR create temporary files in directory DIR
-y, --fuzzy find similar file for basis if no dest file
--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
-z, --compress compress file data during the transfer
--compress-level=NUM explicitly set compression level
--skip-compress=LIST skip compressing files with suffix in LIST
-C, --cvs-exclude auto-ignore files in the same way CVS does
-f, --filter=RULE add a file-filtering RULE
-F same as --filter='dir-merge /.rsync-filter'
repeated: --filter='- .rsync-filter'
--exclude=PATTERN exclude files matching PATTERN
--exclude-from=FILE read exclude patterns from FILE
--include=PATTERN don't exclude files matching PATTERN
--include-from=FILE read include patterns from FILE
--files-from=FILE read list of source-file names from FILE
-0, --from0 all *from/filter files are delimited by 0s
--old-args disable the modern arg-protection idiom
-s, --protect-args no space-splitting; wildcard chars only
--trust-sender trust the remote sender's file list
--address=ADDRESS bind address for outgoing socket to daemon
--port=PORT specify double-colon alternate port number
--sockopts=OPTIONS specify custom TCP options
--blocking-io use blocking I/O for the remote shell
--outbuf=N|L|B set out buffering to None, Line, or Block
--stats give some file-transfer stats
-8, --8-bit-output leave high-bit chars unescaped in output
-h, --human-readable output numbers in a human-readable format
--progress show progress during transfer
-P same as --partial --progress
-i, --itemize-changes output a change-summary for all updates
-M, --remote-option=OPTION send OPTION to the remote side only
--out-format=FORMAT output updates using the specified FORMAT
--log-file=FILE log what we're doing to the specified FILE
--log-file-format=FMT log updates using the specified FMT
--password-file=FILE read daemon-access password from FILE
--list-only list the files instead of copying them
--bwlimit=RATE limit socket I/O bandwidth
--write-batch=FILE write a batched update to FILE
--only-write-batch=FILE like --write-batch but w/o updating dest
--read-batch=FILE read a batched update from FILE
--protocol=NUM force an older protocol version to be used
--iconv=CONVERT_SPEC request charset conversion of filenames
--checksum-seed=NUM set block/file checksum seed (advanced)
-4, --ipv4 prefer IPv4
-6, --ipv6 prefer IPv6
--version print version number
(-h) --help show this help (see below for -h comment)

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

--daemon run as an rsync daemon
--address=ADDRESS bind to the specified address
--bwlimit=RATE limit socket I/O bandwidth
--config=FILE specify alternate rsyncd.conf file
-M, --dparam=OVERRIDE override global daemon config parameter
--no-detach do not detach from the parent
--port=PORT listen on alternate port number
--log-file=FILE override the "log file" setting
--log-file-format=FMT override the "log format" setting
--sockopts=OPTIONS specify custom TCP options
-v, --verbose increase verbosity
-4, --ipv4 prefer IPv4
-6, --ipv6 prefer IPv6
-h, --help show this help (if used after --daemon)

OPTIONS
Rsync accepts both long (double-dash + word) and short (single-dash + letter) options.
The full list of the available options are described below. If an option can be specified
in more than one way, the choices are comma-separated. Some options only have a long
variant, not a short. If the option takes a parameter, the parameter is only listed after
the long variant, even though it must also be specified for the short. When specifying a
parameter, you can either use the form --option=param or replace the '=' with whitespace.
The parameter may need to be quoted in some manner for it to survive the shell's com-
mand-line parsing. Keep in mind that a leading tilde (~) in a filename is substituted by
your shell, so --option=~/foo will not change the tilde into your home directory (remove
the '=' for that).

--help Print a short help page describing the options available in rsync and exit. For
backward-compatibility with older versions of rsync, the help will also be output
if you use the -h option without any other args.

--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 options will
give you information on what files are being skipped and slightly more information
at the end. More than two -v options should only be used if you are debugging
rsync.

In a modern rsync, the -v option is equivalent to the setting of groups of --info
and --debug options. You can choose to use these newer options in addition to, or
in place of using --verbose, as any fine-grained settings override the implied set-
tings of -v. Both --info and --debug have a way to ask for help that tells you ex-
actly what flags are set for each increase in verbosity.

However, do keep in mind that a daemon's "max verbosity" setting will limit how
high of a level the various individual flags can be set on the daemon side. For
instance, if the max is 2, then any info and/or debug flag that is set to a higher
value than what would be set by -vv will be downgraded to the -vv level in the dae-
mon's logging.

--info=FLAGS
This option lets you have fine-grained control over the information output you want
to see. An individual flag name may be followed by a level number, with 0 meaning
to silence that output, 1 being the default output level, and higher numbers in-
creasing the output of that flag (for those that support higher levels). Use
--info=help to see all the available flag names, what they output, and what flag
names are added for each increase in the verbose level. Some examples:

rsync -a --info=progress2 src/ dest/
rsync -avv --info=stats2,misc1,flist0 src/ dest/

Note that --info=name's output is affected by the --out-format and --item-
ize-changes (-i) options. See those options for more information on what is output
and when.

This option was added to 3.1.0, so an older rsync on the server side might reject
your attempts at fine-grained control (if one or more flags needed to be send to
the server and the server was too old to understand them). See also the "max ver-
bosity" caveat above when dealing with a daemon.

--debug=FLAGS
This option lets you have fine-grained control over the debug output you want to
see. An individual flag name may be followed by a level number, with 0 meaning to
silence that output, 1 being the default output level, and higher numbers increas-
ing the output of that flag (for those that support higher levels). Use --de-
bug=help to see all the available flag names, what they output, and what flag names
are added for each increase in the verbose level. Some examples:

rsync -avvv --debug=none src/ dest/
rsync -avA --del --debug=del2,acl src/ dest/

Note that some debug messages will only be output when --msgs2stderr is specified,
especially those pertaining to I/O and buffer debugging.

--msgs2stderr
This option changes rsync to send all its output directly to stderr rather than to
send messages to the client side via the protocol (which normally outputs info mes-
sages via stdout). This is mainly intended for debugging in order to avoid chang-
ing the data sent via the protocol, since the extra protocol data can change what
is being tested. The option does not affect the remote side of a transfer without
using --remote-option -- e.g. -M--msgs2stderr. Also keep in mind that a daemon
connection does not have a stderr channel to send messages back to the client side,
so if you are doing any daemon-transfer debugging using this option, you should
start up a daemon using --no-detach so that you can see the stderr output on the
daemon side.

This option has the side-effect of making stderr output get line-buffered so that
the merging of the output of 3 programs happens in a more readable manner.

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

--no-motd
This option affects the information that is output by the client at the start of a
daemon transfer. This suppresses the message-of-the-day (MOTD) text, but it also
affects the list of modules that the daemon sends in response to the "rsync host::"
request (due to a limitation in the rsync protocol), so omit this option if you
want to request the list of modules from the daemon.

-I, --ignore-times
Normally rsync will skip any files that are already the same size and have the same
modification timestamp. This option turns off this "quick check" behavior, causing
all files to be updated.

--size-only
This modifies rsync's "quick check" algorithm for finding files that need to be
transferred, changing it from the default of transferring files with either a
changed size or a changed last-modified time to just looking for files that have
changed in size. 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
differ by no more than the modify-window value. The default is 0, which matches
just integer seconds. If you specify a negative value (and the receiver is at
least version 3.1.3) then nanoseconds will also be taken into account. Specifying
1 is useful for copies to/from MS Windows FAT filesystems, because FAT represents
times with a 2-second resolution (allowing times to differ from the original by up
to 1 second).

If you want all your transfers to default to comparing nanoseconds, you can create
a ~/.popt file and put these lines in it:

rsync alias -a -a@-1
rsync alias -t -t@-1

With that as the default, you'd need to specify --modify-window=0 (aka -@0) to
override it and ignore nanoseconds, e.g. if you're copying between ext3 and ext4,
or if the receiving rsync is older than 3.1.3.

-c, --checksum
This changes the way rsync checks if the files have been changed and are in need of
a transfer. Without this option, rsync uses a "quick check" that (by default)
checks if each file's size and time of last modification match between the sender
and receiver. This option changes this to compare a 128-bit checksum for each file
that has a matching size. Generating the checksums means that both sides will ex-
pend a lot of disk I/O reading all the data in the files in the transfer (and this
is prior to any reading that will be done to transfer changed files), so this can
slow things down significantly.

The sending side generates its checksums while it is doing the file-system scan
that builds the list of the available files. The receiver generates its checksums
when it is scanning for changed files, and will checksum any file that has the same
size as the corresponding sender's file: files with either a changed size or a
changed checksum are selected for transfer.

Note that rsync always verifies that each transferred file was correctly recon-
structed on the receiving side by checking a whole-file checksum that is generated
as the file is transferred, but that automatic after-the-transfer verification has
nothing to do with this option's before-the-transfer "Does this file need to be up-
dated?" check.

For protocol 30 and beyond (first supported in 3.0.0), the checksum used is MD5.
For older protocols, the checksum used is MD4.

-a, --archive
This is equivalent to -rlptgoD. It is a quick way of saying you want recursion and
want to preserve almost everything (with -H being a notable omission). The only
exception to the above equivalence is when --files-from is specified, in which case
-r is not implied.

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

--no-OPTION
You may turn off one or more implied options by prefixing the option name with
"no-". Not all options may be prefixed with a "no-": only options that are implied
by other options (e.g. --no-D, --no-perms) or have different defaults in various
circumstances (e.g. --no-whole-file, --no-blocking-io, --no-dirs). You may specify
either the short or the long option name after the "no-" prefix (e.g. --no-R is the
same as --no-relative).

For example: if you want to use -a (--archive) but don't want -o (--owner), instead
of converting -a into -rlptgD, you could specify -a --no-o (or -a --no-owner).

The order of the options is important: if you specify --no-r -a, the -r option
would end up being turned on, the opposite of -a --no-r. Note also that the
side-effects of the --files-from option are NOT positional, as it affects the de-
fault state of several options and slightly changes the meaning of -a (see the
--files-from option for more details).

-r, --recursive
This tells rsync to copy directories recursively. See also --dirs (-d).

Beginning with rsync 3.0.0, the recursive algorithm used is now an incremental scan
that uses much less memory than before and begins the transfer after the scanning
of the first few directories have been completed. This incremental scan only af-
fects our recursion algorithm, and does not change a non-recursive transfer. It is
also only possible when both ends of the transfer are at least version 3.0.0.

Some options require rsync to know the full file list, so these options disable the
incremental recursion mode. These include: --delete-before, --delete-after,
--prune-empty-dirs, and --delay-updates. Because of this, the default delete mode
when you specify --delete is now --delete-during when both ends of the connection
are at least 3.0.0 (use --del or --delete-during to request this improved deletion
mode explicitly). See also the --delete-delay option that is a better choice than
using --delete-after.

Incremental recursion can be disabled using the --no-inc-recursive option or its
shorter --no-i-r alias.

-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 this command:

rsync -av /foo/bar/baz.c remote:/tmp/

... this would create a file named baz.c in /tmp/ on the remote machine. If instead
you used

rsync -avR /foo/bar/baz.c remote:/tmp/

then a file named /tmp/foo/bar/baz.c would be created on the remote machine, pre-
serving its full path. These extra path elements are called "implied directories"
(i.e. the "foo" and the "foo/bar" directories in the above example).

Beginning with rsync 3.0.0, rsync always sends these implied directories as real
directories in the file list, even if a path element is really a symlink on the
sending side. This prevents some really unexpected behaviors when copying the full
path of a file that you didn't realize had a symlink in its path. If you want to
duplicate a server-side symlink, include both the symlink via its path, and refer-
ent directory via its real path. If you're dealing with an older rsync on the
sending side, you may need to use the --no-implied-dirs option.

It is also possible to limit the amount of path information that is sent as implied
directories for each path you specify. With a modern rsync on the sending side
(beginning with 2.6.7), you can insert a dot and a slash into the source path, like
this:

rsync -avR /foo/./bar/baz.c remote:/tmp/

That would create /tmp/bar/baz.c on the remote machine. (Note that the dot must be
followed by a slash, so "/foo/." would not be abbreviated.) For older rsync ver-
sions, you would need to use a chdir to limit the source path. For example, when
pushing files:

(cd /foo; rsync -avR bar/baz.c remote:/tmp/)

(Note that the parens put the two commands into a sub-shell, so that the "cd" com-
mand doesn't remain in effect for future commands.) If you're pulling files from
an older rsync, use this idiom (but only for a non-daemon transfer):

rsync -avR --rsync-path="cd /foo; rsync" \
remote:bar/baz.c /tmp/

--no-implied-dirs
This option affects the default behavior of the --relative option. When it is
specified, the attributes of the implied directories from the source names are not
included in the transfer. This means that the corresponding path elements on the
destination system are left unchanged if they exist, and any missing implied direc-
tories are created with default attributes. This even allows these implied path
elements to have big differences, such as being a symlink to a directory on the re-
ceiving side.

For instance, if a command-line arg or a files-from entry told rsync to transfer
the file "path/foo/file", the directories "path" and "path/foo" are implied when
--relative is used. If "path/foo" is a symlink to "bar" on the destination system,
the receiving rsync would ordinarily delete "path/foo", recreate it as a directory,
and receive the file into the new directory. With --no-implied-dirs, the receiving
rsync updates "path/foo/file" using the existing path elements, which means that
the file ends up being created in "path/bar". Another way to accomplish this link
preservation is to use the --keep-dirlinks option (which will also affect symlinks
to directories in the rest of the transfer).

When pulling files from an rsync older than 3.0.0, you may need to use this option
if the sending side has a symlink in the path you request and you wish the implied
directories to be transferred as normal directories.

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

Note that if you don't specify --backup-dir, (1) the --omit-dir-times option will
be forced on, and (2) if --delete is also in effect (without --delete-excluded),
rsync will add a "protect" filter-rule for the backup suffix to the end of all your
existing excludes (e.g. -f "P *~"). This will prevent previously backed-up files
from being deleted. Note that if you are supplying your own filter rules, you may
need to manually insert your own exclude/protect rule 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 inclusion/exclusion of '*', the auto-added rule would never be
reached).

--backup-dir=DIR
In combination with the --backup option, this tells rsync to store all backups in
the specified directory on the receiving side. This can be used 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).

Note that if you specify a relative path, the backup directory will be relative to
the destination directory, so you probably want to specify either an absolute path
or a path that starts with "../". If an rsync daemon is the receiver, the backup
dir cannot go outside the module's path hierarchy, so take extra care not to delete
it or copy into it.

--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 which exist on the destination and have a modi-
fied time that is newer than the source file. (If an existing destination file has
a modification time equal to the source file's, it will be updated if the sizes are
different.)

Note that this does not affect the copying of dirs, symlinks, or other special
files. Also, 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 ob-
jects. In other words, if the source has a directory where the destination has a
file, the transfer would occur regardless of the timestamps.

This option is a transfer rule, not an exclude, so it doesn't affect the data that
goes into the file-lists, and thus it doesn't affect deletions. It just limits the
files that the receiver requests to be transferred.

--inplace
This option changes how rsync transfers a file when its data needs to be updated:
instead of the default method of creating a new copy of the file and moving it into
place when it is complete, rsync instead writes the updated data directly to the
destination file.

This has several effects:

o Hard links are not broken. This means the new data will be visible through
other hard links to the destination file. Moreover, attempts to copy dif-
fering source files onto a multiply-linked destination file will result in a
"tug of war" with the destination data changing back and forth.

o In-use binaries cannot be updated (either the OS will prevent this from hap-
pening, or binaries that attempt to swap-in their data will misbehave or
crash).

o The file's data will be in an inconsistent state during the transfer and
will be left that way if the transfer is interrupted or if an update fails.

o A file that rsync cannot write to cannot be updated. While a super user can
update any file, a normal user needs to be granted write permission for the
open of the file for writing to be successful.

o The efficiency of rsync's delta-transfer algorithm may be reduced if some
data in the destination file is overwritten before it can be copied to a po-
sition later in the file. This does not apply if you use --backup, since
rsync is smart enough to use the backup file as the basis file for the
transfer.

WARNING: you should not use this option to update files that are being accessed by
others, so be careful when choosing to use this for a copy.

This option is useful for transferring large files with block-based changes or ap-
pended data, and also on systems that are disk bound, not network bound. It can
also help keep a copy-on-write filesystem snapshot from diverging the entire con-
tents of a file that only has minor changes.

The option implies --partial (since an interrupted transfer does not delete the
file), but conflicts with --partial-dir and --delay-updates. Prior to rsync 2.6.4
--inplace was also incompatible with --compare-dest and --link-dest.

--append
This causes rsync to update a file by appending data onto the end of the file,
which presumes that the data that already exists on the receiving side is identical
with the start of the file on the sending side. If a file needs to be transferred
and its size on the receiver is the same or longer than the size on the sender, the
file is skipped. This does not interfere with the updating of a file's non-content
attributes (e.g. permissions, ownership, etc.) when the file does not need to be
transferred, nor does it affect the updating of any non-regular files. Implies
--inplace.

The use of --append can be dangerous if you aren't 100% sure that the files that
are longer have only grown by the appending of data onto the end. You should thus
use include/exclude/filter rules to ensure that such a transfer is only affecting
files that you know to be growing via appended data.

--append-verify
This works just like the --append option, but the existing data on the receiving
side is included in the full-file checksum verification step, which will cause a
file to be resent if the final verification step fails (rsync uses a normal,
non-appending --inplace transfer for the resend).

Note: prior to rsync 3.0.0, the --append option worked like --append-verify, so if
you are interacting with an older rsync (or the transfer is using a protocol prior
to 30), specifying either append option will initiate an --append-verify transfer.

-d, --dirs
Tell the sending side to include any directories that are encountered. Unlike
--recursive, a directory's contents are not copied unless the directory name speci-
fied is "." or ends with a trailing slash (e.g. ".", "dir/.", "dir/", etc.). With-
out this option or the --recursive option, rsync will skip all directories it en-
counters (and output a message to that effect for each one). If you specify both
--dirs and --recursive, --recursive takes precedence.

The --dirs option is implied by the --files-from option or the --list-only option
(including an implied --list-only usage) if --recursive wasn't specified (so that
directories are seen in the listing). Specify --no-dirs (or --no-d) if you want to
turn this off.

There is also a backward-compatibility helper option, --old-dirs (or --old-d) that
tells rsync to use a hack of "-r --exclude='/*/*'" to get an older rsync to list a
single directory without recursing.

-l, --links
When symlinks are encountered, recreate the symlink on the destination.

-L, --copy-links
When symlinks are encountered, the item 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 send-
ing files to an rsync that is too old to understand -K -- in that case, the -L op-
tion 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. This option has no
additional effect if --copy-links was also specified.

--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.

--munge-links
This option tells rsync to (1) modify all symlinks on the receiving side in a way
that makes them unusable but recoverable (see below), or (2) to unmunge symlinks on
the sending side that had been stored in a munged state. This is useful if you
don't quite trust the source of the data to not try to slip in a symlink to a unex-
pected place.

The way rsync disables the use of symlinks is to prefix each one with the string
"/rsyncd-munged/". This prevents the links from being used as long as that direc-
tory does not exist. When this option is enabled, rsync will refuse to run if that
path is a directory or a symlink to a directory.

The option only affects the client side of the transfer, so if you need it to af-
fect the server, specify it via --remote-option. (Note that in a local transfer,
the client side is the sender.)

This option has no affect on a daemon, since the daemon configures whether it wants
munged symlinks via its "munge symlinks" parameter. See also the "munge-symlinks"
perl script in the support directory of the source code.

-k, --copy-dirlinks
This option causes the sending side to treat a symlink to a directory as though it
were a real directory. This is useful if you don't want symlinks to non-directo-
ries to be affected, as they would be using --copy-links.

Without this option, if the sending side has replaced a directory with a symlink to
a directory, the receiving side will delete anything that is in the way of the new
symlink, including a directory hierarchy (as long as --force or --delete is in ef-
fect).

See also --keep-dirlinks for an analogous option for the receiving side.

--copy-dirlinks applies to all symlinks to directories in the source. If you want
to follow only a few specified symlinks, a trick you can use is to pass them as ad-
ditional source args with a trailing slash, using --relative to make the paths
match up right. For example:

rsync -r --relative src/./ src/./follow-me/ dest/

This works because rsync calls lstat(2) on the source arg as given, and the trail-
ing slash makes lstat(2) follow the symlink, giving rise to a directory in the
file-list which overrides the symlink found during the scan of "src/./".

-K, --keep-dirlinks
This option causes the receiving side to treat a symlink to a directory as though
it were a real directory, but only if it matches a real directory from the sender.
Without this option, the receiver's symlink would be deleted and replaced with a
real directory.

For example, suppose you transfer a directory "foo" that contains a file "file",
but "foo" is a symlink to directory "bar" on the receiver. Without
--keep-dirlinks, the receiver deletes symlink "foo", recreates it as a directory,
and receives the file into the new directory. With --keep-dirlinks, the receiver
keeps the symlink and "file" ends up in "bar".

One note of caution: if you use --keep-dirlinks, you must trust all the symlinks
in the copy! If it is possible for an untrusted user to create their own symlink
to any directory, the user could then (on a subsequent copy) replace the symlink
with a real directory and affect the content of whatever directory the symlink ref-
erences. For backup copies, you are better off using something like a bind mount
instead of a symlink to modify your receiving hierarchy.

See also --copy-dirlinks for an analogous option for the sending side.

-H, --hard-links
This tells rsync to look for hard-linked files in the source and link together the
corresponding files on the destination. Without this option, hard-linked files in
the source are treated as though they were separate files.

This option does NOT necessarily ensure that the pattern of hard links on the des-
tination exactly matches that on the source. Cases in which the destination may
end up with extra hard links include the following:

o If the destination contains extraneous hard-links (more linking than what is
present in the source file list), the copying algorithm will not break them
explicitly. However, if one or more of the paths have content differences,
the normal file-update process will break those extra links (unless you are
using the --inplace option).

o If you specify a --link-dest directory that contains hard links, the linking
of the destination files against the --link-dest files can cause some paths
in the destination to become linked together due to the --link-dest associa-
tions.

Note that rsync can only detect hard links between files that are inside the trans-
fer set. If rsync updates a file that has extra hard-link connections to files
outside the transfer, that linkage will be broken. If you are tempted to use the
--inplace option to avoid this breakage, be very careful that you know how your
files are being updated so that you are certain that no unintended changes happen
due to lingering hard links (and see the --inplace option for more caveats).

If incremental recursion is active (see --recursive), rsync may transfer a missing
hard-linked file before it finds that another link for that contents exists else-
where in the hierarchy. This does not affect the accuracy of the transfer (i.e.
which files are hard-linked together), just its efficiency (i.e. copying the data
for a new, early copy of a hard-linked file that could have been found later in the
transfer in another member of the hard-linked set of files). One way to avoid this
inefficiency is to disable incremental recursion using the --no-inc-recursive op-
tion.

-p, --perms
This option causes the receiving rsync to set the destination permissions to be the
same as the source permissions. (See also the --chmod option for a way to modify
what rsync considers to be the source permissions.)

When this option is off, permissions are set as follows:

o Existing files (including updated files) retain their existing permissions,
though the --executability option might change just the execute permission
for the file.

o New files get their "normal" permission bits set to the source file's per-
missions masked with the receiving directory's default permissions (either
the receiving process's umask, or the permissions specified via the destina-
tion directory's default ACL), and their special permission bits disabled
except in the case where a new directory inherits a setgid bit from its par-
ent directory.

Thus, when --perms and --executability are both disabled, rsync's behavior is the
same as that of other file-copy utilities, such as cp(1) and tar(1).

In summary: to give destination files (both old and new) the source permissions,
use --perms. To give new files the destination-default permissions (while leaving
existing files unchanged), make sure that the --perms option is off and use
--chmod=ugo=rwX (which ensures that all non-masked bits get enabled). If you'd
care to make this latter behavior easier to type, you could define a popt alias for
it, such as putting this line in the file ~/.popt (the following defines the -Z op-
tion, and includes --no-g to use the default group of the destination dir):

rsync alias -Z --no-p --no-g --chmod=ugo=rwX

You could then use this new option in a command such as this one:

rsync -avZ src/ dest/

(Caveat: make sure that -a does not follow -Z, or it will re-enable the two
"--no-*" options mentioned above.)

The preservation of the destination's setgid bit on newly-created directories when
--perms is off was added in rsync 2.6.7. Older rsync versions erroneously pre-
served the three special permission bits for newly-created files when --perms was
off, while overriding the destination's setgid bit setting on a newly-created di-
rectory. Default ACL observance was added to the ACL patch for rsync 2.6.7, so
older (or non-ACL-enabled) rsyncs use the umask even if default ACLs are present.
(Keep in mind that it is the version of the receiving rsync that affects these be-
haviors.)

-E, --executability
This option causes rsync to preserve the executability (or non-executability) of
regular files when --perms is not enabled. A regular file is considered to be exe-
cutable if at least one 'x' is turned on in its permissions. When an existing des-
tination file's executability differs from that of the corresponding source file,
rsync modifies the destination file's permissions as follows:

o To make a file non-executable, rsync turns off all its 'x' permissions.

o To make a file executable, rsync turns on each 'x' permission that has a
corresponding 'r' permission enabled.

If --perms is enabled, this option is ignored.

-A, --acls
This option causes rsync to update the destination ACLs to be the same as the
source ACLs. The option also implies --perms.

The source and destination systems must have compatible ACL entries for this option
to work properly. See the --fake-super option for a way to backup and restore ACLs
that are not compatible.

-X, --xattrs
This option causes rsync to update the destination extended attributes to be the
same as the source ones.

For systems that support extended-attribute namespaces, a copy being done by a su-
per-user copies all namespaces except system.*. A normal user only copies the
user.* namespace. To be able to backup and restore non-user namespaces as a normal
user, see the --fake-super option.

The above name filtering can be overridden by using one or more filter options with
the x modifier. When you specify an xattr-affecting filter rule, rsync requires
that you do your own system/user filtering, as well as any additional filtering for
what xattr names are copied and what names are allowed to be deleted. For example,
to skip the system namespace, you could specify:

--filter='-x system.*'

To skip all namespaces except the user namespace, you could specify a negated-user
match:

--filter='-x! user.*'

To prevent any attributes from being deleted, you could specify a receiver-only
rule that excludes all names:

--filter='-xr *'

Note that the -X option does not copy rsync's special xattr values (e.g. those
used by --fake-super) unless you repeat the option (e.g. -XX). This "copy all xat-
trs" mode cannot be used with --fake-super.

--chmod
This option tells rsync to apply one or more comma-separated "chmod" modes to the
permission of the files in the transfer. The resulting value is treated as though
it were the permissions that the sending side supplied for the file, which means
that this option can seem to have no effect on existing files if --perms is not en-
abled.

In addition to the normal parsing rules specified in the chmod(1) manpage, you can
specify an item that should only apply to a directory by prefixing it with a 'D',
or specify an item that should only apply to a file by prefixing it with a 'F'.
For example, the following will ensure that all directories get marked set-gid,
that no files are other-writable, that both are user-writable and group-writable,
and that both have consistent executability across all bits:

--chmod=Dg+s,ug+w,Fo-w,+X

Using octal mode numbers is also allowed:

--chmod=D2775,F664

It is also legal to specify multiple --chmod options, as each additional option is
just appended to the list of changes to make.

See the --perms and --executability options for how the resulting permission value
can be applied to the files in the transfer.

-o, --owner
This option causes rsync to set the owner of the destination file to be the same as
the source file, but only if the receiving rsync is being run as the super-user
(see also the --super and --fake-super options). Without this option, the owner of
new and/or transferred files are set to the invoking user on the receiving side.

The preservation of ownership will associate matching names by default, but may
fall back to using the ID number in some circumstances (see also 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 (or if
--no-super was specified), only groups that the invoking user on the receiving side
is a member of will be preserved. Without this option, the group is set to the de-
fault group of the invoking user on the receiving side.

The preservation of group information will associate matching names by default, but
may fall back to using the ID number in some circumstances (see also the --nu-
meric-ids option for a full discussion).

--devices
This option causes rsync to transfer character and block device files to the remote
system to recreate these devices. This option has no effect if the receiving rsync
is not run as the super-user (see also the --super and --fake-super options).

--specials
This option causes rsync to transfer special files such as named sockets and fifos.

-D The -D option is equivalent to --devices --specials.

-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 rsync's delta-transfer algorithm will make
the update fairly efficient if the files haven't actually changed, you're much bet-
ter off using -t).

-O, --omit-dir-times
This tells rsync to omit directories when it is preserving modification times (see
--times). If NFS is sharing the directories on the receiving side, it is a good
idea to use -O. This option is inferred if you use --backup without --backup-dir.

This option also has the side-effect of avoiding early creation of directories in
incremental recursion copies. The default --inc-recursive copying normally does an
early-create pass of all the sub-directories in a parent directory in order for it
to be able to then set the modify time of the parent directory right away (without
having to delay that until a bunch of recursive copying has finished). This
early-create idiom is not necessary if directory modify times are not being pre-
served, so it is skipped. Since early-create directories don't have accurate mode,
mtime, or ownership, the use of this option can help when someone wants to avoid
these partially-finished directories.

-J, --omit-link-times
This tells rsync to omit symlinks when it is preserving modification times (see
--times).

--super
This tells the receiving side to attempt super-user activities even if the receiv-
ing rsync wasn't run by the super-user. These activities include: preserving users
via the --owner option, preserving all groups (not just the current user's groups)
via the --groups option, and copying devices via the --devices option. This is
useful for systems that allow such activities without being the super-user, and
also for ensuring that you will get errors if the receiving side isn't being run as
the super-user. To turn off super-user activities, the super-user can use --no-su-
per.

--fake-super
When this option is enabled, rsync simulates super-user activities by sav-
ing/restoring the privileged attributes via special extended attributes that are
attached to each file (as needed). This includes the file's owner and group (if it
is not the default), the file's device info (device & special files are created as
empty text files), and any permission bits that we won't allow to be set on the
real file (e.g. the real file gets u-s,g-s,o-t for safety) or that would limit the
owner's access (since the real super-user can always access/change a file, the
files we create can always be accessed/changed by the creating user). This option
also handles ACLs (if --acls was specified) and non-user extended attributes (if
--xattrs was specified).

This is a good way to backup data without using a super-user, and to store ACLs
from incompatible systems.

The --fake-super option only affects the side where the option is used. To affect
the remote side of a remote-shell connection, use the --remote-option (-M) option:

rsync -av -M--fake-super /src/ host:/dest/

For a local copy, this option affects both the source and the destination. If you
wish a local copy to enable this option just for the destination files, specify
-M--fake-super. If you wish a local copy to enable this option just for the source
files, combine --fake-super with -M--super.

This option is overridden by both --super and --no-super.

See also the "fake super" setting in the daemon's rsyncd.conf file.

-S, --sparse
Try to handle sparse files efficiently so they take up less space on the destina-
tion. If combined with --inplace the file created might not end up with sparse
blocks with some combinations of kernel version and/or filesystem type. If
--whole-file is in effect (e.g. for a local copy) then it will always work because
rsync truncates the file prior to writing out the updated version.

Note that versions of rsync older than 3.1.3 will reject the combination of
--sparse and --inplace.

--preallocate
This tells the receiver to allocate each destination file to its eventual size be-
fore writing data to the file. Rsync will only use the real filesystem-level pre-
allocation support provided by Linux's fallocate(2) system call or Cygwin's
posix_fallocate(3), not the slow glibc implementation that writes a null byte into
each block.

Without this option, larger files may not be entirely contiguous on the filesystem,
but with this option rsync will probably copy more slowly. If the destination is
not an extent-supporting filesystem (such as ext4, xfs, NTFS, etc.), this option
may have no positive effect at all.

If combined with --sparse, the file will only have sparse blocks (as opposed to al-
located sequences of null bytes) if the kernel version and filesystem type support
creating holes in the allocated data.

-n, --dry-run
This makes rsync perform a trial run that doesn't make any changes (and produces
mostly the same output as a real run). It is most commonly used in combination
with the -v, --verbose and/or -i, --itemize-changes options to see what an rsync
command is going to do before one actually runs it.

The output of --itemize-changes is supposed to be exactly the same on a dry run and
a subsequent real run (barring intentional trickery and system call failures); if
it isn't, that's a bug. Other output should be mostly unchanged, but may differ in
some areas. Notably, a dry run does not send the actual data for file transfers,
so --progress has no effect, the "bytes sent", "bytes received", "literal data",
and "matched data" statistics are too small, and the "speedup" value is equivalent
to a run where no file transfers were needed.

-W, --whole-file
This option disables rsync's delta-transfer algorithm, which causes all transferred
files to be sent whole. 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, but
only if no batch-writing option is in effect.

--checksum-choice=STR
This option overrides the checksum algoriths. If one algorithm name is specified,
it is used for both the transfer checksums and (assuming --checksum is specifed)
the pre-transfer checksumming. If two comma-separated names are supplied, the first
name affects the transfer checksums, and the second name affects the pre-transfer
checksumming.

The algorithm choices are "auto", "md4", "md5", and "none". If "none" is specified
for the first name, the --whole-file option is forced on and no checksum verifica-
tion is performed on the transferred data. If "none" is specified for the second
name, the --checksum option cannot be used. The "auto" option is the default, where
rsync bases its algorithm choice on the protocol version (for backward compatibil-
ity with older rsync versions).

-x, --one-file-system
This tells rsync to avoid crossing a filesystem boundary when recursing. This does
not limit the user's ability to specify items to copy from multiple filesystems,
just rsync's recursion through the hierarchy of each directory that the user speci-
fied, and also the analogous recursion on the receiving side during deletion. Also
keep in mind that rsync treats a "bind" mount to the same device as being on the
same filesystem.

If this option is repeated, rsync omits all mount-point directories from the copy.
Otherwise, it includes an empty directory at each mount-point it encounters (using
the attributes of the mounted directory because those of the underlying mount-point
directory are inaccessible).

If rsync has been told to collapse symlinks (via --copy-links or --copy-un-
safe-links), a symlink to a directory on another device is treated like a
mount-point. Symlinks to non-directories are unaffected by this option.

--existing, --ignore-non-existing
This tells rsync to skip creating files (including directories) that do not exist
yet on the destination. If this option is combined with the --ignore-existing op-
tion, no files will be updated (which can be useful if all you want to do is delete
extraneous files).

--ignore-existing
This tells rsync to skip updating files that already exist on the destination (this
does not ignore existing directories, or nothing would get done). See also --ex-
isting.

This option can be useful for those doing backups using the --link-dest option when
they need to continue a backup run that got interrupted. Since a --link-dest run
is copied into a new directory hierarchy (when it is used properly), using --ignore
existing will ensure that the already-handled files don't get tweaked (which avoids
a change in permissions on the hard-linked files). This does mean that this option
is only looking at the existing files in the destination hierarchy itself.

--remove-source-files
This tells rsync to remove from the sending side the files (meaning non-directo-
ries) that are a part of the transfer and have been successfully duplicated on the
receiving side.

Note that you should only use this option on source files that are quiescent. If
you are using this to move files that show up in a particular directory over to an-
other host, make sure that the finished files get renamed into the source direc-
tory, not directly written into it, so that rsync can't possibly transfer a file
that is not yet fully written. If you can't first write the files into a different
directory, you should use a naming idiom that lets rsync avoid transferring files
that are not yet finished (e.g. name the file "foo.new" when it is written, rename
it to "foo" when it is done, and then use the option --exclude='*.new' for the
rsync transfer).

Starting with 3.1.0, rsync will skip the sender-side removal (and output an error)
if the file's size or modify time has not stayed unchanged.

--delete
This tells rsync to delete extraneous files from the receiving side (ones that
aren't on the sending side), but only for the directories that are being synchro-
nized. You must have asked rsync to send the whole directory (e.g. "dir" or
"dir/") without using a wildcard for the directory's contents (e.g. "dir/*") since
the wildcard is expanded by the shell and rsync thus gets a request to transfer in-
dividual files, not the files' parent directory. Files that are excluded from the
transfer are also excluded from being deleted unless you use the --delete-excluded
option or mark the rules as only matching on the sending side (see the include/ex-
clude modifiers in the FILTER RULES section).

Prior to rsync 2.6.7, this option would have no effect unless --recursive was en-
abled. Beginning with 2.6.7, deletions will also occur when --dirs (-d) is en-
abled, but only for directories whose contents are being copied.

This option can be dangerous if used incorrectly! It is a very good idea to first
try a run using the --dry-run option (-n) to see what files are going to be
deleted.

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 from causing a massive deletion
of files on the destination. You can override this with the --ignore-errors op-
tion.

The --delete option may be combined with one of the --delete-WHEN options without
conflict, as well as --delete-excluded. However, if none of the --delete-WHEN op-
tions are specified, rsync will choose the --delete-during algorithm when talking
to rsync 3.0.0 or newer, and the --delete-before algorithm when talking to an older
rsync. See also --delete-delay and --delete-after.

--delete-before
Request that the file-deletions on the receiving side be done before the transfer
starts. See --delete (which is implied) for more details on file-deletion.

Deleting before the transfer is helpful if the filesystem is tight for space and
removing extraneous files would help to make the transfer possible. However, it
does introduce a delay before the start of the transfer, and this delay might cause
the transfer to timeout (if --timeout was specified). It also forces rsync to use
the old, non-incremental recursion algorithm that requires rsync to scan all the
files in the transfer into memory at once (see --recursive).

--delete-during, --del
Request that the file-deletions on the receiving side be done incrementally as the
transfer happens. The per-directory delete scan is done right before each direc-
tory is checked for updates, so it behaves like a more efficient --delete-before,
including doing the deletions prior to any per-directory filter files being up-
dated. This option was first added in rsync version 2.6.4. See --delete (which is
implied) for more details on file-deletion.

--delete-delay
Request that the file-deletions on the receiving side be computed during the trans-
fer (like --delete-during), and then removed after the transfer completes. This is
useful when combined with --delay-updates and/or --fuzzy, and is more efficient
than using --delete-after (but can behave differently, since --delete-after com-
putes the deletions in a separate pass after all updates are done). If the number
of removed files overflows an internal buffer, a temporary file will be created on
the receiving side to hold the names (it is removed while open, so you shouldn't
see it during the transfer). If the creation of the temporary file fails, rsync
will try to fall back to using --delete-after (which it cannot do if --recursive is
doing an incremental scan). See --delete (which is implied) for more details on
file-deletion.

--delete-after
Request that the file-deletions on the receiving side be done after the transfer
has completed. This is useful if you are sending new per-directory merge files as
a part of the transfer and you want their exclusions to take effect for the delete
phase of the current transfer. It also forces rsync to use the old, non-incremen-
tal recursion algorithm that requires rsync to scan all the files in the transfer
into memory at once (see --recursive). See --delete (which is implied) for more
details on file-deletion.

--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 ex-
cluded (see --exclude). See the FILTER RULES section for a way to make individual
exclusions behave this way on the receiver, and for a way to protect files from
--delete-excluded. See --delete (which is implied) for more details on file-dele-
tion.

--ignore-missing-args
When rsync is first processing the explicitly requested source files (e.g. com-
mand-line arguments or --files-from entries), it is normally an error if the file
cannot be found. This option suppresses that error, and does not try to transfer
the file. This does not affect subsequent vanished-file errors if a file was ini-
tially found to be present and later is no longer there.

--delete-missing-args
This option takes the behavior of (the implied) --ignore-missing-args option a step
farther: each missing arg will become a deletion request of the corresponding des-
tination file on the receiving side (should it exist). If the destination file is
a non-empty directory, it will only be successfully deleted if --force or --delete
are in effect. Other than that, this option is independent of any other type of
delete processing.

The missing source files are represented by special file-list entries which display
as a "*missing" entry in the --list-only output.

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

--force
This option tells rsync to delete a non-empty directory when it is to be replaced
by a non-directory. This is only relevant if deletions are not active (see
--delete for details).

Note for older rsync versions: --force used to still be required when using
--delete-after, and it used to be non-functional unless the --recursive option was
also enabled.

--max-delete=NUM
This tells rsync not to delete more than NUM files or directories. If that limit
is exceeded, all further deletions are skipped through the end of the transfer. At
the end, rsync outputs a warning (including a count of the skipped deletions) and
exits with an error code of 25 (unless some more important error condition also oc-
curred).

Beginning with version 3.0.0, you may specify --max-delete=0 to be warned about any
extraneous files in the destination without removing any of them. Older clients
interpreted this as "unlimited", so if you don't know what version the client is,
you can use the less obvious --max-delete=-1 as a backward-compatible way to spec-
ify that no deletions be allowed (though really old versions didn't warn when the
limit was exceeded).

--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 string to indicate a size multiplier,
and may be a fractional value (e.g. "--max-size=1.5m").

The suffixes are as follows: "K" (or "KiB") is a kibibyte (1024), "M" (or "MiB") is
a mebibyte (1024*1024), and "G" (or "GiB") is a gibibyte (1024*1024*1024). If you
want the multiplier to be 1000 instead of 1024, use "KB", "MB", or "GB". (Note:
lower-case is also accepted for all values.) Finally, if the suffix ends in either
"+1" or "-1", the value will be offset by one byte in the indicated direction.

Examples: --max-size=1.5mb-1 is 1499999 bytes, and --max-size=2g+1 is 2147483649
bytes.

Note that rsync versions prior to 3.1.0 did not allow --max-size=0.

--min-size=SIZE
This tells rsync to avoid transferring any file that is smaller than the specified
SIZE, which can help in not transferring small, junk files. See the --max-size op-
tion for a description of SIZE and other information.

Note that rsync versions prior to 3.1.0 did not allow --min-size=0.

-B, --block-size=BLOCKSIZE
This forces the block size used in rsync's delta-transfer 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 daemon on the remote host, and all data will be trans-
mitted through that remote shell connection, rather than through a direct socket
connection to a running rsync daemon on the remote host. See the section "USING
RSYNC-DAEMON FEATURES VIA A REMOTE-SHELL CONNECTION" above.

Command-line arguments are permitted in COMMAND provided that COMMAND is presented
to rsync as a single argument. You must use spaces (not tabs or other whitespace)
to separate the command and args from each other, and you can use single- and/or
double-quotes to preserve spaces in an argument (but not backslashes). Note that
doubling a single-quote inside a single-quoted string gives you a single-quote;
likewise for double-quotes (though you need to pay attention to which quotes your
shell is parsing and which quotes rsync is parsing). Some examples:

-e 'ssh -p 2234'
-e 'ssh -o "ProxyCommand nohup ssh firewall nc -w1 %h %p"'

(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 vari-
able, which accepts the same range of values as -e.

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

--rsync-path=PROGRAM
Use this to specify what program is to be run on the remote machine to start-up
rsync. Often used when rsync is not in the default remote-shell's path (e.g.
--rsync-path=/usr/local/bin/rsync). Note that PROGRAM is run with the help of a
shell, so it can be any program, script, or command sequence you'd care to run, so
long as it does not corrupt the standard-in & standard-out that rsync is using to
communicate.

One tricky example is to set a different default directory on the remote machine
for use with the --relative option. For instance:

rsync -avR --rsync-path="cd /a/b && rsync" host:c/d /e/

-M, --remote-option=OPTION
This option is used for more advanced situations where you want certain effects to
be limited to one side of the transfer only. For instance, if you want to pass
--log-file=FILE and --fake-super to the remote system, specify it like this:

rsync -av -M --log-file=foo -M--fake-super src/ dest/

If you want to have an option affect only the local side of a transfer when it nor-
mally affects both sides, send its negation to the remote side. Like this:

rsync -av -x -M--no-x src/ dest/

Be cautious using this, as it is possible to toggle an option that will cause rsync
to have a different idea about what data to expect next over the socket, and that
will make it fail in a cryptic fashion.

Note that you should use a separate -M for each remote option you want to pass. On
older rsync versions, the presence of any spaces in the remote-option arg could
cause it to be split into separate remote args, but this requires the use of
--old-args in this version of rsync.

When performing a local transfer, the "local" side is the sender and the "remote"
side is the receiver.

Note some versions of the popt option-parsing library have a bug in them that pre-
vents you from using an adjacent arg with an equal in it next to a short option
letter (e.g. -M--log-file=/tmp/foo). If this bug affects your version of popt, you
can use the version of popt that is included with rsync.

-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 a similar algorithm to CVS to de-
termine if a file should be ignored.

The exclude list is initialized to exclude the following items (these initial items
are marked as perishable -- see the FILTER RULES section):

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/ .git/ .hg/ .bzr/

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 white-
space).

Finally, any file is ignored if it is in the same directory as a .cvsignore file
and matches one of the patterns listed therein. Unlike rsync's filter/exclude
files, these patterns are split on whitespace. See the cvs(1) manual for more in-
formation.

If you're combining -C with your own --filter rules, you should note that these CVS
excludes are appended at the end of your own rules, regardless of where the -C was
placed on the command-line. This makes them a lower priority than any rules you
specified explicitly. If you want to control where these CVS excludes get inserted
into your filter rules, you should omit the -C as a command-line option and use a
combination of --filter=:C and --filter=-C (either on your command-line or by
putting the ":C" and "-C" rules into a filter file with your other rules). The
first option turns on the per-directory scanning for the .cvsignore file. The sec-
ond option does a one-time import of the CVS excludes mentioned above.

-f, --filter=RULE
This option allows you to add rules to selectively exclude certain files from the
list of files to be transferred. This is most useful in combination with a recur-
sive transfer.

You may use as many --filter options on the command line as you like to build up
the list of files to exclude. If the filter contains whitespace, be sure to quote
it so that the shell gives the rule to rsync as a single argument. The text below
also mentions that you can use an underscore to replace the space that separates a
rule from its arg.

See the FILTER RULES section for detailed information on this option.

-F The -F option is a shorthand for adding two --filter rules to your command. The
first time it is used is a shorthand for this rule:

--filter='dir-merge /.rsync-filter'

This tells rsync to look for per-directory .rsync-filter files that have been
sprinkled through the hierarchy and use their rules to filter the files in the
transfer. If -F is repeated, it is a shorthand for this rule:

--filter='exclude .rsync-filter'

This filters out the .rsync-filter files themselves from the transfer.

See the FILTER RULES section for detailed information on how these options work.

--exclude=PATTERN
This option is a simplified form of the --filter option that defaults to an exclude
rule and does not allow the full rule-parsing syntax of normal filter rules.

See the FILTER RULES section for detailed information on this option.

--exclude-from=FILE
This option is related to the --exclude option, but it specifies a FILE that con-
tains exclude patterns (one per line). Blank lines in the file and lines starting
with ';' or '#' are ignored. If FILE is -, the list will be read from standard in-
put.

--include=PATTERN
This option is a simplified form of the --filter option that defaults to an include
rule and does not allow the full rule-parsing syntax of normal filter rules.

See the FILTER RULES section for detailed information on this option.

--include-from=FILE
This option is related to the --include option, but it specifies a FILE that con-
tains include patterns (one per line). Blank lines in the file and lines starting
with ';' or '#' are ignored. If FILE is -, the list will be read from standard in-
put.

--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:

o The --relative (-R) option is implied, which preserves the path information
that is specified for each item in the file (use --no-relative or --no-R if
you want to turn that off).

o The --dirs (-d) option is implied, which will create directories specified
in the list on the destination rather than noisily skipping them (use
--no-dirs or --no-d if you want to turn that off).

o The --archive (-a) option's behavior does not imply --recursive (-r), so
specify it explicitly, if you want it.

o These side-effects change the default state of rsync, so the position of the
--files-from option on the command-line has no bearing on how other options
are parsed (e.g. -a works the same before or after --files-from, as does
--no-R and all other options).

The filenames 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. If it contains "bin/" (note the
trailing slash), the immediate contents of the directory would also be sent (with-
out needing to be explicitly mentioned in the file -- this began in version 2.6.4).
In both cases, if the -r option was enabled, that dir's entire hierarchy would also
be transferred (keep in mind that -r needs to be specified explicitly with
--files-from, since it is not implied by -a). Also note 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 lo-
cated on the remote "src" host.

If the --iconv and --protect-args options are specified and the --files-from file-
names are being sent from one host to another, the filenames will be translated
from the sending host's charset to the receiving host's charset.

NOTE: sorting the list of files in the --files-from input helps rsync to be more
efficient, as it will avoid re-visiting the path elements that are shared between
adjacent entries. If the input is not sorted, some path elements (implied directo-
ries) may end up being scanned multiple times, and rsync will eventually undupli-
cate them after they get turned into file-list elements.

-0, --from0
This tells rsync that the rules/filenames it reads from a file are terminated by a
null ('\0') character, not a NL, CR, or CR+LF. This affects --exclude-from, --in-
clude-from, --files-from, and any merged files specified in a --filter rule. It
does not affect --cvs-exclude (since all names read from a .cvsignore file are
split on whitespace).

--old-args
This option tells rsync to stop trying to protect the arg values from unintended
word-splitting or other misinterpretation by using its new backslash-escape idiom.
The newest default is for remote filenames to only allow wildcards characters to be
interpretated by the shell while protecting other shell-interpreted characters (and
the args of options get even wildcards escaped). The only active wildcard charac-
ters on the remote side are: `*`, `?`, `[`, & `]`.

If you have a script that wants to use old-style arg splitting in the filenames,
specify this option once. If the remote shell has a problem with any backslash es-
capes, specify the option twice.

You may also control this setting via the RSYNC_OLD_ARGS environment variable. If
it has the value "1", rsync will default to a single-option setting. If it has the
value "2" (or more), rsync will default to a repeated-option setting. If it is
"0", you'll get the default escaping behavior. The environment is always overrid-
den by manually specified positive or negative options (the negative is
--no-old-args).

Note that this option also disables the extra safety check added in this version of
rsync, that ensures that a remote sender isn't including extra top-level items in
the file-list that you didn't request. This side-effect is necessary because we
can't know for sure what names to expect when the remote shell is interpreting the
args.

This option conflicts with the --protect-args option.

-s, --protect-args
This option sends all filenames and most options to the remote rsync without allow-
ing the remote shell to interpret them. Wildcards are expanded on the remote host
by rsync instead of the shell doing it.

This is similar to the new-style backslash-escaping of args that was added in this
version of rsync, but supports some extra features and doesn't rely on backslash
escaping in the remote shell.

If you use this option with --iconv, the args related to the remote side will also
be translated from the local to the remote character-set. The translation happens
before wild-cards are expanded. See also the --files-from option.

You may also control this setting via the RSYNC_PROTECT_ARGS environment variable.
If it has a non-zero value, this setting will be enabled by default, otherwise it
will be disabled by default. Either state is overridden by a manually specified
positive or negative version of this option (note that --no-s and --no-protect-args
are the negative versions). This environment variable is also superseded by a non-
zero RSYNC_OLD_ARGS export.

You may need to disable this option when interacting with an older rsync (one prior
to 3.0.0).

This option conflicts with the --old-args option.

Note that this option is incompatible with the use of the restricted rsync script
(`rrsync`) since it hides options from the script's inspection.

--trust-sender
Disable the extra validation of the file list from a remote sender (this safety
feature was added to address the performance downgrade after fixing CVE
2022-29154). This should only be done if you trust the sender to not try to do
something malicious, which should be the case if they're running a stock rsync.

Normally when pulling files from a remote rsync, the client runs 2 extra validation
checks:

o Verify that additional arg items didn't get added at the top of the trans-
fer.

o Verify that none of the items in the file list should have been excluded.

Note that various options can turn off one or both of these checks if the option
interferes with the validation. For instance:

o Using a per-directory filter file reads filter rules that only the server
knows about, so the filter checking is disabled.

o Using the --old-args option allows the sender to manipulate the requested
args, so the arg checking is disabled.

o Reading the files-from list from the server side means that the client
doesn't know the arg list, so the arg checking is disabled.

o Using --read-batch disables both checks since the batch file's contents will
have been verified when it was created.

This option may help an under-powered client server if the extra pattern matching
is slowing things down on a huge transfer. It can also be used to work around a
bug in the verification logic, possibly after using the --list-only option combined
with --trust-sender to look over the full file list.

-T, --temp-dir=DIR
This option instructs rsync to use DIR as a scratch directory when creating tempo-
rary copies of the files transferred on the receiving side. The default behavior
is to create each temporary file in the same directory as the associated destina-
tion file. Beginning with rsync 3.1.1, the temp-file names inside the specified
DIR will not be prefixed with an extra dot (though they will still have a random
suffix added).

This option is most often used when the receiving disk partition does not have
enough free space to hold a copy of the largest file in the transfer. In this case
(i.e. when the scratch directory is on a different disk partition), rsync will not
be able to rename each received temporary file over the top of the associated des-
tination file, but instead must copy it into place. Rsync does this by copying the
file over the top of the destination file, which means that the destination file
will contain truncated data during this copy. If this were not done this way (even
if the destination file were first removed, the data locally copied to a temporary
file in the destination directory, and then renamed into place) it would be possi-
ble for the old file to continue taking up disk space (if someone had it open), and
thus there might not be enough room to fit the new version on the disk at the same
time.

If you are using this option for reasons other than a shortage of disk space, you
may wish to combine it with the --delay-updates option, which will ensure that all
copied files get put into subdirectories in the destination hierarchy, awaiting the
end of the transfer. If you don't have enough room to duplicate all the arriving
files on the destination partition, another way to tell rsync that you aren't
overly concerned about disk space is to use the --partial-dir option with a rela-
tive path; because this tells rsync that it is OK to stash off a copy of a single
file in a subdir in the destination hierarchy, rsync will use the partial-dir as a
staging area to bring over the copied file, and then rename it into place from
there. (Specifying a --partial-dir with an absolute path does not have this
side-effect.)

-y, --fuzzy
This option tells rsync that it should look for a basis file for any destination
file that is missing. The current algorithm looks in the same directory as the
destination file for either a file that has an identical size and modified-time, or
a similarly-named file. If found, rsync uses the fuzzy basis file to try to speed
up the transfer.

If the option is repeated, the fuzzy scan will also be done in any matching alter-
nate destination directories that are specified via --compare-dest, --copy-dest, or
--link-dest.

Note that the use of the --delete option might get rid of any potential fuzzy-match
files, so either use --delete-after or specify some filename exclusions if you need
to prevent this.

--compare-dest=DIR
This option instructs rsync to use 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 DIR that is identical
to the sender's file, the file will NOT be transferred to the destination direc-
tory. This is useful for creating a sparse backup of just files that have changed
from an earlier backup. This option is typically used to copy into an empty (or
newly created) directory.

Beginning in version 2.6.4, multiple --compare-dest directories may be provided,
which will cause rsync to search the list in the order specified for an exact
match. If a match is found that differs only in attributes, a local copy is made
and the attributes updated. If a match is not found, a basis file from one of the
DIRs will be selected to try to speed up the transfer.

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

NOTE: beginning with version 3.1.0, rsync will remove a file from a non-empty des-
tination hierarchy if an exact match is found in one of the compare-dest hierar-
chies (making the end result more closely match a fresh copy).

--copy-dest=DIR
This option behaves like --compare-dest, but rsync will also copy unchanged files
found in DIR to the destination directory using a local 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.

Multiple --copy-dest directories may be provided, which will cause rsync to search
the list in the order specified for an unchanged file. If a match is not found, a
basis file from one of the DIRs will be selected to try to speed up the transfer.

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

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

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

If file's aren't linking, double-check their attributes. Also check if some at-
tributes are getting forced outside of rsync's control, such a mount option that
squishes root to a single user, or mounts a removable drive with generic ownership
(such as OS X's "Ignore ownership on this volume" option).

Beginning in version 2.6.4, multiple --link-dest directories may be provided, which
will cause rsync to search the list in the order specified for an exact match
(there is a limit of 20 such directories). If a match is found that differs only
in attributes, a local copy is made and the attributes updated. If a match is not
found, a basis file from one of the DIRs will be selected to try to speed up the
transfer.

This option works best when copying into an empty destination hierarchy, as exist-
ing files may get their attributes tweaked, and that can affect alternate destina-
tion files via hard-links. Also, itemizing of changes can get a bit muddled. Note
that prior to version 3.1.0, an alternate-directory exact match would never be
found (nor linked into the destination) when a destination file already exists.

Note that if you combine this option with --ignore-times, rsync will not link any
files together because it only links identical files together as a substitute for
transferring the file, never as an additional check after the file is updated.

If 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-super-user when -o was specified (or implied by
-a). You can work-around this bug by avoiding the -o option when sending to an old
rsync.

-z, --compress
With this option, rsync compresses the file data as it is sent to the destination
machine, which reduces the amount of data being transmitted -- something that is
useful over a slow connection.

Note that this option typically achieves better compression ratios than can be
achieved by using a compressing remote shell or a compressing transport because it
takes advantage of the implicit information in the matching data blocks that are
not explicitly sent over the connection. This matching-data compression comes at a
cost of CPU, though, and can be disabled by repeating the -z option, but only if
both sides are at least version 3.1.1.

Note that if your version of rsync was compiled with an external zlib (instead of
the zlib that comes packaged with rsync) then it will not support the old-style
compression, only the new-style (repeated-option) compression. In the future this
new-style compression will likely become the default.

The client rsync requests new-style compression on the server via the --new-com-
press option, so if you see that option rejected it means that the server is not
new enough to support -zz. Rsync also accepts the --old-compress option for a fu-
ture time when new-style compression becomes the default.

See the --skip-compress option for the default list of file suffixes that will not
be compressed.

--compress-level=NUM
Explicitly set the compression level to use (see --compress) instead of letting it
default. If NUM is non-zero, the --compress option is implied.

--skip-compress=LIST
Override the list of file suffixes that will not be compressed. The LIST should be
one or more file suffixes (without the dot) separated by slashes (/).

You may specify an empty string to indicate that no file should be skipped.

Simple character-class matching is supported: each must consist of a list of let-
ters inside the square brackets (e.g. no special classes, such as "[:alpha:]", are
supported, and '-' has no special meaning).

The characters asterisk (*) and question-mark (?) have no special meaning.

Here's an example that specifies 6 suffixes to skip (since 1 of the 5 rules matches
2 suffixes):

--skip-compress=gz/jpg/mp[34]/7z/bz2

The default list of suffixes that will not be compressed is this (in this version
of rsync):

7z ace avi bz2 deb gpg gz iso jpeg jpg lz lzma lzo mov mp3 mp4 ogg png rar rpm rzip
tbz tgz tlz txz xz z zip

This list will be replaced by your --skip-compress list in all but one situation: a
copy from a daemon rsync will add your skipped suffixes to its list of non-com-
pressing files (and its list may be configured to a different default).

--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 des-
tination 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 infor-
mation 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.

--usermap=STRING, --groupmap=STRING
These options allow you to specify users and groups that should be mapped to other
values by the receiving side. The STRING is one or more FROM:TO pairs of values
separated by commas. Any matching FROM value from the sender is replaced with a TO
value from the receiver. You may specify usernames or user IDs for the FROM and TO
values, and the FROM value may also be a wild-card string, which will be matched
against the sender's names (wild-cards do NOT match against ID numbers, though see
below for why a '*' matches everything). You may instead specify a range of ID
numbers via an inclusive range: LOW-HIGH. For example:

--usermap=0-99:nobody,wayne:admin,*:normal --groupmap=usr:1,1:usr

The first match in the list is the one that is used. You should specify all your
user mappings using a single --usermap option, and/or all your group mappings using
a single --groupmap option.

Note that the sender's name for the 0 user and group are not transmitted to the re-
ceiver, so you should either match these values using a 0, or use the names in ef-
fect on the receiving side (typically "root"). All other FROM names match those in
use on the sending side. All TO names match those in use on the receiving side.

Any IDs that do not have a name on the sending side are treated as having an empty
name for the purpose of matching. This allows them to be matched via a "*" or us-
ing an empty name. For instance:

--usermap=:nobody --groupmap=*:nobody

When the --numeric-ids option is used, the sender does not send any names, so all
the IDs are treated as having an empty name. This means that you will need to
specify numeric FROM values if you want to map these nameless IDs to different val-
ues.

For the --usermap option to have any effect, the -o (--owner) option must be used
(or implied), and the receiver will need to be running as a super-user (see also
the --fake-super option). For the --groupmap option to have any effect, the -g
(--groups) option must be used (or implied), and the receiver will need to have
permissions to set that group.

An older rsync client may need to use --protect-args (-s) to avoid a complaint
about wildcard characters, but a modern rsync handles this automatically.

--chown=USER:GROUP
This option forces all files to be owned by USER with group GROUP. This is a sim-
pler interface than using --usermap and --groupmap directly, but it is implemented
using those options internally, so you cannot mix them. If either the USER or
GROUP is empty, no mapping for the omitted user/group will occur. If GROUP is
empty, the trailing colon may be omitted, but if USER is empty, a leading colon
must be supplied.

If you specify "--chown=foo:bar, this is exactly the same as specifying
"--usermap=*:foo --groupmap=*:bar", only easier.

An older rsync client may need to use --protect-args (-s) to avoid a complaint
about wildcard characters, but a modern rsync handles this automatically.

--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.

--contimeout
This option allows you to set the amount of time that rsync will wait for its con-
nection to an rsync daemon to succeed. If the timeout is reached, rsync exits with
an error.

--address
By default rsync will bind to the wildcard address when connecting to an rsync dae-
mon. The --address option allows you to specify a specific IP address (or host-
name) to bind to. See also this option in the --daemon mode section.

--port=PORT
This specifies an alternate TCP port number to use rather than the default of 873.
This is only needed if you are using the double-colon (::) syntax to connect with
an rsync daemon (since the URL syntax has a way to specify the port as a part of
the URL). See also this option in the --daemon mode section.

--sockopts
This option can provide endless fun for people who like to tune their systems to
the utmost degree. You can set all sorts of socket options which may make transfers
faster (or slower!). Read the man page for the setsockopt() system call for details
on some of the options you may be able to set. By default no special socket options
are set. This only affects direct socket connections to a remote rsync daemon.
This option also exists in the --daemon mode section.

--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, oth-
erwise it defaults to using non-blocking I/O. (Note that ssh prefers non-blocking
I/O.)

--outbuf=MODE
This sets the output buffering mode. The mode can be None (aka Unbuffered), Line,
or Block (aka Full). You may specify as little as a single letter for the mode,
and use upper or lower case.

The main use of this option is to change Full buffering to Line buffering when
rsync's output is going to a file or pipe.

-i, --itemize-changes
Requests a simple itemized list of the changes that are being made to each file,
including attribute changes. This is exactly the same as specifying --out-for-
mat='%i %n%L'. If you repeat the option, unchanged files will also be output, but
only if the receiving rsync is at least version 2.6.7 (you can use -vv with older
versions of rsync, but that also turns on the output of other verbose messages).

The "%i" escape has a cryptic output that is 11 letters long. The general format
is like the string YXcstpoguax, where Y is replaced by the type of update being
done, X is replaced by the file-type, and the other letters represent attributes
that may be output if they are being modified.

The update types that replace the Y are as follows:

o A < means that a file is being transferred to the remote host (sent).

o A > means that a file is being transferred to the local host (received).

o A c means that a local change/creation is occurring for the item (such as
the creation of a directory or the changing of a symlink, etc.).

o A h means that the item is a hard link to another item (requires
--hard-links).

o A . means that the item is not being updated (though it might have at-
tributes that are being modified).

o A * means that the rest of the itemized-output area contains a message (e.g.
"deleting").

The file-types that replace the X are: f for a file, a d for a directory, an L for
a symlink, a D for a device, and a S for a special file (e.g. named sockets and fi-
fos).

The other letters in the string above are the actual letters that will be output if
the associated attribute for the item is being updated or a "." for no change.
Three exceptions to this are: (1) a newly created item replaces each letter with a
"+", (2) an identical item replaces the dots with spaces, and (3) an unknown attri-
bute replaces each letter with a "?" (this can happen when talking to an older
rsync).

The attribute that is associated with each letter is as follows:

o A c means either that a regular file has a different checksum (requires
--checksum) or that a symlink, device, or special file has a changed value.
Note that if you are sending files to an rsync prior to 3.0.1, this change
flag will be present only for checksum-differing regular files.

o A s means the size of a regular file is different and will be updated by the
file transfer.

o A t means the modification time is different and is being updated to the
sender's value (requires --times). An alternate value of T means that the
modification time will be set to the transfer time, which happens when a
file/symlink/device is updated without --times and when a symlink is changed
and the receiver can't set its time. (Note: when using an rsync 3.0.0
client, you might see the s flag combined with t instead of the proper T
flag for this time-setting failure.)

o A p means the permissions are different and are being updated to the
sender's value (requires --perms).

o An o means the owner is different and is being updated to the sender's value
(requires --owner and super-user privileges).

o A g means the group is different and is being updated to the sender's value
(requires --group and the authority to set the group).

o The u slot is reserved for future use.

o The a means that the ACL information changed.

o The x means that the extended attribute information changed.

One other output is possible: when deleting files, the "%i" will output the string
"*deleting" for each item that is being removed (assuming that you are talking to a
recent enough rsync that it logs deletions instead of outputting them as a verbose
message).

--out-format=FORMAT
This allows you to specify exactly what the rsync client outputs to the user on a
per-update basis. The format is a text string containing embedded single-character
escape sequences prefixed with a percent (%) character. A default format of
"%n%L" is assumed if either --info=name or -v is specified (this tells you just the
name of the file and, if the item is a link, where it points). For a full list of
the possible escape characters, see the "log format" setting in the rsyncd.conf
manpage.

Specifying the --out-format option implies the --info=name option, which will men-
tion each file, dir, etc. that gets updated in a significant way (a transferred
file, a recreated symlink/device, or a touched directory). In addition, if the
itemize-changes escape (%i) is included in the string (e.g. if the --item-
ize-changes option was used), the logging of names increases to mention any item
that is changed in any way (as long as the receiving side is at least 2.6.4). See
the --itemize-changes option for a description of the output of "%i".

Rsync will output the out-format string prior to a file's transfer unless one of
the transfer-statistic escapes is requested, in which case the logging is done at
the end of the file's transfer. When this late logging is in effect and --progress
is also specified, rsync will also output the name of the file being transferred
prior to its progress information (followed, of course, by the out-format output).

--log-file=FILE
This option causes rsync to log what it is doing to a file. This is similar to the
logging that a daemon does, but can be requested for the client side and/or the
server side of a non-daemon transfer. If specified as a client option, transfer
logging will be enabled with a default format of "%i %n%L". See the
--log-file-format option if you wish to override this.

Here's a example command that requests the remote side to log what is happening:

rsync -av --remote-option=--log-file=/tmp/rlog src/ dest/

This is very useful if you need to debug why a connection is closing unexpectedly.

--log-file-format=FORMAT
This allows you to specify exactly what per-update logging is put into the file
specified by the --log-file option (which must also be specified for this option to
have any effect). If you specify an empty string, updated files will not be men-
tioned in the log file. For a list of the possible escape characters, see the "log
format" setting in the rsyncd.conf manpage.

The default FORMAT used if --log-file is specified and this option is not is '%i
%n%L'.

--stats
This tells rsync to print a verbose set of statistics on the file transfer, allow-
ing you to tell how effective rsync's delta-transfer algorithm is for your data.
This option is equivalent to --info=stats2 if combined with 0 or 1 -v options, or
--info=stats3 if combined with 2 or more -v options.

The current statistics are as follows:

o Number of files is the count of all "files" (in the generic sense), which
includes directories, symlinks, etc. The total count will be followed by a
list of counts by filetype (if the total is non-zero). For example: "(reg:
5, dir: 3, link: 2, dev: 1, special: 1)" lists the totals for regular files,
directories, symlinks, devices, and special files. If any of value is 0, it
is completely omitted from the list.

o Number of created files is the count of how many "files" (generic sense)
were created (as opposed to updated). The total count will be followed by a
list of counts by filetype (if the total is non-zero).

o Number of deleted files is the count of how many "files" (generic sense)
were created (as opposed to updated). The total count will be followed by a
list of counts by filetype (if the total is non-zero). Note that this line
is only output if deletions are in effect, and only if protocol 31 is being
used (the default for rsync 3.1.x).

o Number of regular files transferred is the count of normal files that were
updated via rsync's delta-transfer algorithm, which does not include dirs,
symlinks, etc. Note that rsync 3.1.0 added the word "regular" into this
heading.

o Total file size is the total sum of all file sizes in the transfer. This
does not count any size for directories or special files, but does include
the size of symlinks.

o Total transferred file size is the total sum of all files sizes for just the
transferred files.

o Literal data is how much unmatched file-update data we had to send to the
receiver for it to recreate the updated files.

o Matched data is how much data the receiver got locally when recreating the
updated files.

o File list size is how big the file-list data was when the sender sent it to
the receiver. This is smaller than the in-memory size for the file list due
to some compressing of duplicated data when rsync sends the list.

o File list generation time is the number of seconds that the sender spent
creating the file list. This requires a modern rsync on the sending side
for this to be present.

o File list transfer time is the number of seconds that the sender spent send-
ing the file list to the receiver.

o Total bytes sent is the count of all the bytes that rsync sent from the
client side to the server side.

o Total bytes received is the count of all non-message bytes that rsync re-
ceived by the client side from the server side. "Non-message" bytes means
that we don't count the bytes for a verbose message that the server sent to
us, which makes the stats more consistent.

-8, --8-bit-output
This tells rsync to leave all high-bit characters unescaped in the output instead
of trying to test them to see if they're valid in the current locale and escaping
the invalid ones. All control characters (but never tabs) are always escaped, re-
gardless of this option's setting.

The escape idiom that started in 2.6.7 is to output a literal backslash (\) and a
hash (#), followed by exactly 3 octal digits. For example, a newline would output
as "\#012". A literal backslash that is in a filename is not escaped unless it is
followed by a hash and 3 digits (0-9).

-h, --human-readable
Output numbers in a more human-readable format. There are 3 possible levels: (1)
output numbers with a separator between each set of 3 digits (either a comma or a
period, depending on if the decimal point is represented by a period or a comma);
(2) output numbers in units of 1000 (with a character suffix for larger units --
see below); (3) output numbers in units of 1024.

The default is human-readable level 1. Each -h option increases the level by one.
You can take the level down to 0 (to output numbers as pure digits) by specifing
the --no-human-readable (--no-h) option.

The unit letters that are appended in levels 2 and 3 are: K (kilo), M (mega), G
(giga), or T (tera). For example, a 1234567-byte file would output as 1.23M in
level-2 (assuming that a period is your local decimal point).

Backward compatibility note: versions of rsync prior to 3.1.0 do not support hu-
man-readable level 1, and they default to level 0. Thus, specifying one or two -h
options will behave in a comparable manner in old and new versions as long as you
didn't specify a --no-h option prior to one or more -h options. See the
--list-only option for one difference.

--partial
By default, rsync will delete any partially transferred file if the transfer is in-
terrupted. 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
A better way to keep partial files than the --partial option is to specify a DIR
that will be used to hold the partial data (instead of writing it out to the desti-
nation file). On the next transfer, rsync will use a file found in this dir as
data to speed up the resumption of the transfer and then delete it after it has
served its purpose.

Note that if --whole-file is specified (or implied), any partial-dir file that is
found for a file that is being updated will simply be removed (since rsync is send-
ing files without using rsync's delta-transfer 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 "--par-
tial-dir=.rsync-partial") to have rsync create the partial-directory in the desti-
nation file's directory when needed, and then remove it again when the partial file
is deleted.

If the partial-dir value is not an absolute path, rsync will add an exclude rule at
the end of all your existing excludes. This will prevent the sending of any par-
tial-dir files that may exist on the sending side, and will also prevent the un-
timely deletion of partial-dir items on the receiving side. An example: the above
--partial-dir option would add the equivalent of "-f '-p .rsync-partial/'" at the
end of any other filter rules.

If you are supplying your own exclude rules, you may need to add your own ex-
clude/hide/protect rule for the partial-dir because (1) the auto-added rule may be
ineffective at the end of your other rules, or (2) you may wish to override rsync's
exclude choice. For instance, if you want to make rsync clean-up any left-over
partial-dirs that may be lying around, you should specify --delete-after and add a
"risk" filter rule, e.g. -f 'R .rsync-partial/'. (Avoid using --delete-before or
--delete-during unless you don't need rsync to use any of the left-over partial-dir
data during the current run.)

IMPORTANT: the --partial-dir should not be writable by other users or it is a secu-
rity 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 affects where partial files go when --partial is specified. For instance, in-
stead of using --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 times that
the --partial option does not look for this environment value are (1) when --in-
place was specified (since --inplace conflicts with --partial-dir), and (2) when
--delay-updates was specified (see below).

For the purposes of the daemon-config's "refuse options" setting, --partial-dir
does not imply --partial. This is so that a refusal of the --partial option can be
used to disallow the overwriting of destination files with a partial transfer,
while still allowing the safer idiom provided by --partial-dir.

--delay-updates
This option puts the temporary file from each updated file into a holding directory
until the end of the transfer, at which time all the files are renamed into place
in rapid succession. This attempts to make the updating of the files a little more
atomic. By default the files are placed into a directory named ".~tmp~" in each
file's destination directory, but if you've specified the --partial-dir option,
that directory will be used instead. See the comments in the --partial-dir section
for a discussion of how this ".~tmp~" dir will be excluded from the transfer, and
what you can do if you want rsync to cleanup old ".~tmp~" dirs that might be lying
around. Conflicts with --inplace and --append.

This option uses more memory on the receiving side (one bit per file transferred)
and also requires enough free disk space on the receiving side to hold an addi-
tional copy of all the updated files. Note also that you should not use an abso-
lute path to --partial-dir unless (1) there is no chance of any of the files in the
transfer having the same name (since all the updated files will be put into a sin-
gle directory if the path is absolute) and (2) there are no mount points in the hi-
erarchy (since the delayed updates will fail if they can't be renamed into place).

See also the "atomic-rsync" perl script in the "support" subdir for an update algo-
rithm that is even more atomic (it uses --link-dest and a parallel hierarchy of
files).

-m, --prune-empty-dirs
This option tells the receiving rsync to get rid of empty directories from the
file-list, including nested directories that have no non-directory children. This
is useful for avoiding the creation of a bunch of useless directories when the
sending rsync is recursively scanning a hierarchy of files using include/ex-
clude/filter rules.

Note that the use of transfer rules, such as the --min-size option, does not affect
what goes into the file list, and thus does not leave directories empty, even if
none of the files in a directory match the transfer rule.

Because the file-list is actually being pruned, this option also affects what di-
rectories get deleted when a delete is active. However, keep in mind that excluded
files and directories can prevent existing items from being deleted due to an ex-
clude both hiding source files and protecting destination files. See the perish-
able filter-rule option for how to avoid this.

You can prevent the pruning of certain empty directories from the file-list by us-
ing a global "protect" filter. For instance, this option would ensure that the di-
rectory "emptydir" was kept in the file-list:

--filter 'protect emptydir/'

Here's an example that copies all .pdf files in a hierarchy, only creating the nec-
essary destination directories to hold the .pdf files, and ensures that any super-
fluous files and directories in the destination are removed (note the hide filter
of non-directories being used instead of an exclude):

rsync -avm --del --include='*.pdf' -f 'hide,! */' src/ dest

If you didn't want to remove superfluous destination files, the more time-honored
options of "--include='*/' --exclude='*'" would work fine in place of the hide-fil-
ter (if that is more natural to you).

--progress
This option tells rsync to print information showing the progress of the transfer.
This gives a bored user something to watch. With a modern rsync this is the same
as specifying --info=flist2,name,progress, but any user-supplied settings for those
info flags takes precedence (e.g. "--info=flist0 --progress").

While rsync is transferring a regular file, it updates a progress line that looks
like this:

782448 63% 110.64kB/s 0:00:04

In this example, the receiver has reconstructed 782448 bytes or 63% of the sender's
file, which is being reconstructed at a rate of 110.64 kilobytes per second, and
the transfer will finish in 4 seconds if the current rate is maintained until the
end.

These statistics can be misleading if rsync's delta-transfer algorithm is in use.
For example, if the sender's file consists of the basis file followed by additional
data, the reported rate will probably drop dramatically when the receiver gets to
the literal data, and the transfer will probably take much longer to finish than
the receiver estimated as it was finishing the matched part of the file.

When the file transfer finishes, rsync replaces the progress line with a summary
line that looks like this:

1,238,099 100% 146.38kB/s 0:00:08 (xfr#5, to-chk=169/396)

In this example, the file was 1,238,099 bytes long in total, the average rate of
transfer for the whole file was 146.38 kilobytes per second over the 8 seconds that
it took to complete, it was the 5th transfer of a regular file during the current
rsync session, and there are 169 more files for the receiver to check (to see if
they are up-to-date or not) remaining out of the 396 total files in the file-list.

In an incremental recursion scan, rsync won't know the total number of files in the
file-list until it reaches the ends of the scan, but since it starts to transfer
files during the scan, it will display a line with the text "ir-chk" (for incremen-
tal recursion check) instead of "to-chk" until the point that it knows the full
size of the list, at which point it will switch to using "to-chk". Thus, seeing
"ir-chk" lets you know that the total count of files in the file list is still go-
ing to increase (and each time it does, the count of files left to check will in-
crease by the number of the files added to the list).

-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 inter-
rupted.

There is also a --info=progress2 option that outputs statistics based on the whole
transfer, rather than individual files. Use this flag without outputting a file-
name (e.g. avoid -v or specify --info=name0) if you want to see how the transfer is
doing without scrolling the screen with a lot of names. (You don't need to specify
the --progress option in order to use --info=progress2.)

--password-file=FILE
This option allows you to provide a password for accessing an rsync daemon via a
file or via standard input if FILE is -. The file should contain just the password
on the first line (all other lines are ignored). Rsync will exit with an error if
FILE is world readable or if a root-run rsync command finds a non-root-owned file.

This option does not supply a password to a remote shell transport such as ssh; to
learn how to do that, consult the remote shell's documentation. When accessing an
rsync daemon using a remote shell as the transport, this option only comes into ef-
fect after the remote shell finishes its authentication (i.e. if you have also
specified a password in the daemon's config file).

--list-only
This option will cause the source files to be listed instead of transferred. This
option is inferred if there is a single source arg and no destination specified, so
its main uses are: (1) to turn a copy command that includes a destination arg into
a file-listing command, or (2) to be able to specify more than one source arg
(note: be sure to include the destination). Caution: keep in mind that a source
arg with a wild-card is expanded by the shell into multiple args, so it is never
safe to try to list such an arg without using this option. For example:

rsync -av --list-only foo* dest/

Starting with rsync 3.1.0, the sizes output by --list-only are affected by the
--human-readable option. By default they will contain digit separators, but higher
levels of readability will output the sizes with unit suffixes. Note also that the
column width for the size output has increased from 11 to 14 characters for all hu-
man-readable levels. Use --no-h if you want just digits in the sizes, and the old
column width of 11 characters.

Compatibility note: when requesting a remote listing of files from an rsync that
is version 2.6.3 or older, you may encounter an error if you ask for a non-recur-
sive listing. This is because a file listing implies the --dirs option w/o --re-
cursive, and older rsyncs don't have that option. To avoid this problem, either
specify the --no-dirs option (if you don't need to expand a directory's content),
or turn on recursion and exclude the content of subdirectories: -r --ex-
clude='/*/*'.

--bwlimit=RATE
This option allows you to specify the maximum transfer rate for the data sent over
the socket, specified in units per second. The RATE value can be suffixed with a
string to indicate a size multiplier, and may be a fractional value (e.g.
"--bwlimit=1.5m"). If no suffix is specified, the value will be assumed to be in
units of 1024 bytes (as if "K" or "KiB" had been appended). See the --max-size op-
tion for a description of all the available suffixes. A value of zero specifies no
limit.

For backward-compatibility reasons, the rate limit will be rounded to the nearest
KiB unit, so no rate smaller than 1024 bytes per second is possible.

Rsync writes data over the socket in blocks, and this option both limits the size
of the blocks that rsync writes, and tries to keep the average transfer rate at the
requested limit. Some "burstiness" may be seen where rsync writes out a block of
data and then sleeps to bring the average rate into compliance.

Due to the internal buffering of data, the --progress option may not be an accurate
reflection on how fast the data is being sent. This is because some files can show
up as being rapidly sent when the data is quickly buffered, while other can show up
as very slow when the flushing of the output buffer occurs. This may be fixed in a
future version.

--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, and also the
--only-write-batch option.

--only-write-batch=FILE
Works like --write-batch, except that no updates are made on the destination system
when creating the batch. This lets you transport the changes to the destination
system via some other means and then apply the changes via --read-batch.

Note that you can feel free to write the batch directly to some portable media: if
this media fills to capacity before the end of the transfer, you can just apply
that partial transfer to the destination and repeat the whole process to get the
rest of the changes (as long as you don't mind a partially updated destination sys-
tem while the multi-update cycle is happening).

Also note that you only save bandwidth when pushing changes to a remote system be-
cause this allows the batched data to be diverted from the sender into the batch
file without having to flow over the wire to the receiver (when pulling, the sender
is remote, and thus can't write the batch).

--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.

--protocol=NUM
Force an older protocol version to be used. This is useful for creating a batch
file that is compatible with an older version of rsync. For instance, if rsync
2.6.4 is being used with the --write-batch option, but rsync 2.6.3 is what will be
used to run the --read-batch option, you should use "--protocol=28" when creating
the batch file to force the older protocol version to be used in the batch file
(assuming you can't upgrade the rsync on the reading system).

--iconv=CONVERT_SPEC
Rsync can convert filenames between character sets using this option. Using a CON-
VERT_SPEC of "." tells rsync to look up the default character-set via the locale
setting. Alternately, you can fully specify what conversion to do by giving a lo-
cal and a remote charset separated by a comma in the order --iconv=LOCAL,REMOTE,
e.g. --iconv=utf8,iso88591. This order ensures that the option will stay the same
whether you're pushing or pulling files. Finally, you can specify either
--no-iconv or a CONVERT_SPEC of "-" to turn off any conversion. The default set-
ting of this option is site-specific, and can also be affected via the RSYNC_ICONV
environment variable.

For a list of what charset names your local iconv library supports, you can run
"iconv --list".

If you specify the --protect-args option (-s), rsync will translate the filenames
you specify on the command-line that are being sent to the remote host. See also
the --files-from option.

Note that rsync does not do any conversion of names in filter files (including in-
clude/exclude files). It is up to you to ensure that you're specifying matching
rules that can match on both sides of the transfer. For instance, you can specify
extra include/exclude rules if there are filename differences on the two sides that
need to be accounted for.

When you pass an --iconv option to an rsync daemon that allows it, the daemon uses
the charset specified in its "charset" configuration parameter regardless of the
remote charset you actually pass. Thus, you may feel free to specify just the lo-
cal charset for a daemon transfer (e.g. --iconv=utf8).

-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 con-
tacting an rsync daemon. See also these options in the --daemon mode section.

If rsync was complied without support for IPv6, the --ipv6 option will have no ef-
fect. The --version output will tell you if this is the case.

--checksum-seed=NUM
Set the checksum seed to the integer NUM. This 4 byte checksum seed is included in
each block and MD4 file checksum calculation (the more modern MD5 file checksums
don't use a seed). By default the checksum seed is generated by the server and de-
faults to the current time() . This option is used to set a specific checksum
seed, which is useful for applications that want repeatable block checksums, or in
the case where the user wants a more random checksum seed. Setting NUM to 0 causes
rsync to use the default of time() for checksum seed.

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

--daemon
This tells rsync that it is to run as a daemon. The daemon you start running may
be accessed using an rsync client 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 in-
etd, 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.

--address
By default rsync will bind to the wildcard address when run as a daemon with the
--daemon option. 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. See also the "address" global option in the rsyncd.conf man-
page.

--bwlimit=RATE
This option allows you to specify the maximum transfer rate for the data the daemon
sends over the socket. The client can still specify a smaller --bwlimit value, but
no larger value will be allowed. See the client version of this option (above) for
some extra details.

--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 the super-user; in
that case the default is rsyncd.conf in the current directory (typically $HOME).

-M, --dparam=OVERRIDE
This option can be used to set a daemon-config parameter when starting up rsync in
daemon mode. It is equivalent to adding the parameter at the end of the global
settings prior to the first module's definition. The parameter names can be speci-
fied without spaces, if you so desire. For instance:

rsync --daemon -M pidfile=/path/rsync.pid

--no-detach
When running as a daemon, this option instructs rsync to not detach itself and be-
come 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 dae-
montools 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 in-
etd or sshd.

--port=PORT
This specifies an alternate TCP port number for the daemon to listen on rather than
the default of 873. See also the "port" global option in the rsyncd.conf manpage.

--log-file=FILE
This option tells the rsync daemon to use the given log-file name instead of using
the "log file" setting in the config file.

--log-file-format=FORMAT
This option tells the rsync daemon to use the given FORMAT string instead of using
the "log format" setting in the config file. It also enables "transfer logging"
unless the string is empty, in which case transfer logging is turned off.

--sockopts
This overrides the socket options setting in the rsyncd.conf file and has the same
syntax.

-v, --verbose
This option increases the amount of information the daemon logs during its startup
phase. After the client connects, the daemon's verbosity level will be controlled
by the options that the client used and the "max verbosity" setting in the module's
config section.

-4, --ipv4 or -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).

If rsync was complied without support for IPv6, the --ipv6 option will have no ef-
fect. The --version output will tell you if this is the case.

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

FILTER RULES
The filter rules allow for flexible selection of which files to transfer (include) and
which files to skip (exclude). The rules either directly specify include/exclude patterns
or they specify a way to acquire more include/exclude patterns (e.g. to read them from a
file).

As the list of files/directories to transfer is built, rsync checks each name to be trans-
ferred against the list of include/exclude patterns in turn, and the first matching pat-
tern is acted on: if it is an exclude pattern, then that file is skipped; if it is an in-
clude pattern then that filename is not skipped; if no matching pattern is found, then the
filename is not skipped.

Rsync builds an ordered list of filter rules as specified on the command-line. Filter
rules have the following syntax:

RULE [PATTERN_OR_FILENAME]
RULE,MODIFIERS [PATTERN_OR_FILENAME]

You have your choice of using either short or long RULE names, as described below. If you
use a short-named rule, the ',' separating the RULE from the MODIFIERS is optional. The
PATTERN or FILENAME that follows (when present) must come after either a single space or
an underscore (_). Here are the available rule prefixes:

exclude, - specifies an exclude pattern.
include, + specifies an include pattern.
merge, . specifies a merge-file to read for more rules.
dir-merge, : specifies a per-directory merge-file.
hide, H specifies a pattern for hiding files from the transfer.
show, S files that match the pattern are not hidden.
protect, P specifies a pattern for protecting files from deletion.
risk, R files that match the pattern are not protected.
clear, ! clears the current include/exclude list (takes no arg)

When rules are being read from a file, empty lines are ignored, as are comment lines that
start with a "#".

Note that the --include/--exclude command-line options do not allow the full range of rule
parsing as described above -- they only allow the specification of include/exclude pat-
terns plus a "!" token to clear the list (and the normal comment parsing when rules are
read from a file). If a pattern does not begin with "- " (dash, space) or "+ " (plus,
space), then the rule will be interpreted as if "+ " (for an include option) or "- " (for
an exclude option) were prefixed to the string. A --filter option, on the other hand,
must always contain either a short or long rule name at the start of the rule.

Note also that the --filter, --include, and --exclude options take one rule/pattern each.
To add multiple ones, you can repeat the options on the command-line, use the merge-file
syntax of the --filter option, or the --include-from/--exclude-from options.

INCLUDE/EXCLUDE PATTERN RULES
You can include and exclude files by specifying patterns using the "+", "-", etc. filter
rules (as introduced in the FILTER RULES section above). The include/exclude rules each
specify a pattern that is matched against the names of the files that are going to be
transferred. These patterns can take several forms:

o if the pattern starts with a / then it is anchored to a particular spot in the hi-
erarchy of files, otherwise it is matched against the end of the pathname. This is
similar to a leading ^ in regular expressions. Thus "/foo" would match a name of
"foo" at either the "root of the transfer" (for a global rule) or in the
merge-file's directory (for a per-directory rule). An unqualified "foo" would
match a name of "foo" anywhere in the tree because the algorithm is applied recur-
sively from the top down; it behaves as if each path component gets a turn at being
the end of the filename. Even the unanchored "sub/foo" would match at any point in
the hierarchy where a "foo" was found within a directory named "sub". See the sec-
tion on ANCHORING INCLUDE/EXCLUDE PATTERNS for a full discussion of how to specify
a pattern that matches at the root of the transfer.

o if the pattern ends with a / then it will only match a directory, not a regular
file, symlink, or device.

o rsync chooses between doing a simple string match and wildcard matching by checking
if the pattern contains one of these three wildcard characters: '*', '?', and '[' .

o a '*' matches any path component, but it stops at slashes.

o use '**' to match anything, including slashes.

o a '?' matches any character except a slash (/).

o a '[' introduces a character class, such as [a-z] or [[:alpha:]].

o in a wildcard pattern, a backslash can be used to escape a wildcard character, but
it is matched literally when no wildcards are present. This means that there is an
extra level of backslash removal when a pattern contains wildcard characters com-
pared to a pattern that has none. e.g. if you add a wildcard to "foo\bar" (which
matches the backslash) you would need to use "foo\\bar*" to avoid the "\b" becoming
just "b".

o if the pattern contains a / (not counting a trailing /) or a "**", then it is
matched against the full pathname, including any leading directories. If the pat-
tern doesn't contain a / or a "**", then it is matched only against the final com-
ponent of the filename. (Remember that the algorithm is applied recursively so
"full filename" can actually be any portion of a path from the starting directory
on down.)

o a trailing "dir_name/***" will match both the directory (as if "dir_name/" had been
specified) and everything in the directory (as if "dir_name/**" had been speci-
fied). This behavior was added in version 2.6.7.

Note that, when using the --recursive (-r) option (which is implied by -a), every subdir
component of every path is visited left to right, with each directory having a chance for
exclusion before its content. In this way include/exclude patterns are applied recur-
sively to the pathname of each node in the filesystem's tree (those inside the transfer).
The exclude patterns short-circuit the directory traversal stage as rsync finds the files
to send.

For instance, to include "/foo/bar/baz", the directories "/foo" and "/foo/bar" must not be
excluded. Excluding one of those parent directories prevents the examination of its con-
tent, cutting off rsync's recursion into those paths and rendering the include for
"/foo/bar/baz" ineffectual (since rsync can't match something it never sees in the cut-off
section of the directory hierarchy).

The concept path exclusion 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: "+ */" (put it
somewhere before the "- *" rule), and perhaps use the --prune-empty-dirs option. 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:

o "- *.o" would exclude all names matching *.o

o "- /foo" would exclude a file (or directory) named foo in the transfer-root direc-
tory

o "- foo/" would exclude any directory named foo

o "- /foo/*/bar" would exclude any file named bar which is at two levels below a di-
rectory named foo in the transfer-root directory

o "- /foo/**/bar" would exclude any file named bar two or more levels below a direc-
tory named foo in the transfer-root directory

o The combination of "+ */", "+ *.c", and "- *" would include all directories and C
source files but nothing else (see also the --prune-empty-dirs option)

o The combination of "+ foo/", "+ foo/bar.c", and "- *" would include only the foo
directory and foo/bar.c (the foo directory must be explicitly included or it would
be excluded by the "*")

The following modifiers are accepted after a "+" or "-":

o A / specifies that the include/exclude rule should be matched against the absolute
pathname of the current item. For example, "-/ /etc/passwd" would exclude the
passwd file any time the transfer was sending files from the "/etc" directory, and
"-/ subdir/foo" would always exclude "foo" when it is in a dir named "subdir", even
if "foo" is at the root of the current transfer.

o A ! specifies that the include/exclude should take effect if the pattern fails to
match. For instance, "-! */" would exclude all non-directories.

o A C is used to indicate that all the global CVS-exclude rules should be inserted as
excludes in place of the "-C". No arg should follow.

o An s is used to indicate that the rule applies to the sending side. When a rule
affects the sending side, it prevents files from being transferred. The default is
for a rule to affect both sides unless --delete-excluded was specified, in which
case default rules become sender-side only. See also the hide (H) and show (S)
rules, which are an alternate way to specify sending-side includes/excludes.

o An r is used to indicate that the rule applies to the receiving side. When a rule
affects the receiving side, it prevents files from being deleted. See the s modi-
fier for more info. See also the protect (P) and risk (R) rules, which are an al-
ternate way to specify receiver-side includes/excludes.

o A p indicates that a rule is perishable, meaning that it is ignored in directories
that are being deleted. For instance, the -C option's default rules that exclude
things like "CVS" and "*.o" are marked as perishable, and will not prevent a direc-
tory that was removed on the source from being deleted on the destination.

o An x indicates that a rule affects xattr names in xattr copy/delete operations (and
is thus ignored when matching file/dir names). If no xattr-matching rules are spec-
ified, a default xattr filtering rule is used (see the --xattrs option).

MERGE-FILE FILTER RULES
You can merge whole files into your filter rules by specifying either a merge (.) or a
dir-merge (:) filter rule (as introduced in the FILTER RULES section above).

There are two kinds of merged files -- single-instance ('.') and per-directory (':'). A
single-instance merge file is read one time, and its rules are incorporated into the fil-
ter list in the place of the "." rule. For per-directory merge files, rsync will scan ev-
ery directory that it traverses for the named file, merging its contents when the file ex-
ists into the current list of inherited rules. These per-directory rule files must be
created on the sending side because it is the sending side that is being scanned for the
available files to transfer. These rule files may also need to be transferred to the re-
ceiving side if you want them to affect what files don't get deleted (see PER-DIRECTORY
RULES AND DELETE below).

Some examples:

merge /etc/rsync/default.rules
. /etc/rsync/default.rules
dir-merge .per-dir-filter
dir-merge,n- .non-inherited-per-dir-excludes
:n- .non-inherited-per-dir-excludes

The following modifiers are accepted after a merge or dir-merge rule:

o A - specifies that the file should consist of only exclude patterns, with no other
rule-parsing except for in-file comments.

o A + specifies that the file should consist of only include patterns, with no other
rule-parsing except for in-file comments.

o A C is a way to specify that the file should be read in a CVS-compatible manner.
This turns on 'n', 'w', and '-', but also allows the list-clearing token (!) to be
specified. If no filename is provided, ".cvsignore" is assumed.

o A e will exclude the merge-file name from the transfer; e.g. "dir-merge,e .rules"
is like "dir-merge .rules" and "- .rules".

o An n specifies that the rules are not inherited by subdirectories.

o A w specifies that the rules are word-split on whitespace instead of the normal
line-splitting. This also turns off comments. Note: the space that separates the
prefix from the rule is treated specially, so "- foo + bar" is parsed as two rules
(assuming that prefix-parsing wasn't also disabled).

o You may also specify any of the modifiers for the "+" or "-" rules (above) in order
to have the rules that are read in from the file default to having that modifier
set (except for the ! modifier, which would not be useful). For instance,
"merge,-/ .excl" would treat the contents of .excl as absolute-path excludes, while
"dir-merge,s .filt" and ":sC" would each make all their per-directory rules apply
only on the sending side. If the merge rule specifies sides to affect (via the s
or r modifier or both), then the rules in the file must not specify sides (via a
modifier or a rule prefix such as hide).

Per-directory rules are inherited in all subdirectories of the directory where the
merge-file was found unless the 'n' modifier was used. Each subdirectory's rules are pre-
fixed to the inherited per-directory rules from its parents, which gives the newest rules
a higher priority than the inherited rules. The entire set of dir-merge rules are grouped
together in the spot where the merge-file was specified, so it is possible to override
dir-merge rules via a rule that got specified earlier in the list of global rules. When
the list-clearing rule ("!") is read from a per-directory file, it only clears the inher-
ited rules for the current merge file.

Another way to prevent a single rule from a dir-merge file from being inherited is to an-
chor it with a leading slash. Anchored rules in a per-directory merge-file are relative
to the merge-file's directory, so a pattern "/foo" would only match the file "foo" in the
directory where the dir-merge filter file was found.

Here's an example filter file which you'd specify via --filter=". file":

merge /home/user/.global-filter
- *.gz
dir-merge .rules
+ *.[ch]
- *.o

This will merge the contents of the /home/user/.global-filter file at the start of the
list and also turns the ".rules" filename into a per-directory filter file. All rules
read in prior to the start of the directory scan follow the global anchoring rules (i.e. a
leading slash matches at the root of the transfer).

If a per-directory merge-file is specified with a path that is a parent directory of the
first transfer directory, rsync will scan all the parent dirs from that starting point to
the transfer directory for the indicated per-directory file. For instance, here is a com-
mon filter (see -F):

--filter=': /.rsync-filter'

That rule tells rsync to scan for the file .rsync-filter in all directories from the root
down through the parent directory of the transfer prior to the start of the normal direc-
tory scan of the file in the directories that are sent as a part of the transfer. (Note:
for an rsync daemon, the root is always the same as the module's "path".)

Some examples of this pre-scanning for per-directory files:

rsync -avF /src/path/ /dest/dir
rsync -av --filter=': ../../.rsync-filter' /src/path/ /dest/dir
rsync -av --filter=': .rsync-filter' /src/path/ /dest/dir

The first two commands above will look for ".rsync-filter" in "/" and "/src" before the
normal scan begins looking for the file in "/src/path" and its subdirectories. The last
command avoids the parent-dir scan and only looks for the ".rsync-filter" files in each
directory that is a part of the transfer.

If you want to include the contents of a ".cvsignore" in your patterns, you should use the
rule ":C", which creates a dir-merge of the .cvsignore file, but parsed in a CVS-compati-
ble manner. You can use this to affect where the --cvs-exclude (-C) option's inclusion of
the per-directory .cvsignore file gets placed into your rules by putting the ":C" wherever
you like in your filter rules. Without this, rsync would add the dir-merge rule for the
.cvsignore file at the end of all your other rules (giving it a lower priority than your
command-line rules). For example:

cat <<EOT | rsync -avC --filter='. -' a/ b
+ foo.o
:C
- *.old
EOT
rsync -avC --include=foo.o -f :C --exclude='*.old' a/ b

Both of the above rsync commands are identical. Each one will merge all the per-directory
.cvsignore rules in the middle of the list rather than at the end. This allows their
dir-specific rules to supersede the rules that follow the :C instead of being subservient
to all your rules. To affect the other CVS exclude rules (i.e. the default list of exclu-
sions, the contents of $HOME/.cvsignore, and the value of $CVSIGNORE) you should omit the
-C command-line option and instead insert a "-C" rule into your filter rules; e.g. "--fil-
ter=-C".

LIST-CLEARING FILTER RULE
You can clear the current include/exclude list by using the "!" filter rule (as introduced
in the FILTER RULES section above). The "current" list is either the global list of rules
(if the rule is encountered while parsing the filter options) or a set of per-directory
rules (which are inherited in their own sub-list, so a subdirectory can use this to clear
out the parent's rules).

ANCHORING INCLUDE/EXCLUDE PATTERNS
As mentioned earlier, global include/exclude patterns are anchored at the "root of the
transfer" (as opposed to per-directory patterns, which are anchored at the merge-file's
directory). If you think of the transfer as a subtree of names that are being sent from
sender to receiver, the transfer-root is where the tree starts to be duplicated in the
destination directory. This root governs where patterns that start with a / match.

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 host). 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 filter is to just look at the output when us-
ing --verbose and put a / in front of the name (use the --dry-run option if you're not yet
ready to copy any files).

PER-DIRECTORY RULES AND DELETE
Without a delete option, per-directory rules are only relevant on the sending side, so you
can feel free to exclude the merge files themselves without affecting the transfer. To
make this easy, the 'e' modifier adds this exclude for you, as seen in these two equiva-
lent commands:

rsync -av --filter=': .excl' --exclude=.excl host:src/dir /dest
rsync -av --filter=':e .excl' host:src/dir /dest

However, if you want to do a delete on the receiving side AND you want some files to be
excluded from being deleted, you'll need to be sure that the receiving side knows what
files to exclude. The easiest way is to include the per-directory merge files in the
transfer and use --delete-after, because this ensures that the receiving side gets all the
same exclude rules as the sending side before it tries to delete anything:

rsync -avF --delete-after host:src/dir /dest

However, if the merge files are not a part of the transfer, you'll need to either specify
some global exclude rules (i.e. specified on the command line), or you'll need to maintain
your own per-directory merge files on the receiving side. An example of the first is this
(assume that the remote .rules files exclude themselves):

rsync -av --filter=': .rules' --filter='. /my/extra.rules'
--delete host:src/dir /dest

In the above example the extra.rules file can affect both sides of the transfer, but (on
the sending side) the rules are subservient to the rules merged from the .rules files be-
cause they were specified after the per-directory merge rule.

In one final example, the remote side is excluding the .rsync-filter files from the trans-
fer, but we want to use our own .rsync-filter files to control what gets deleted on the
receiving side. To do this we must specifically exclude the per-directory merge files (so
that they don't get deleted) and then put rules into the local files to control what else
should not get deleted. Like one of these commands:

rsync -av --filter=':e /.rsync-filter' --delete \
host:src/dir /dest
rsync -avFF --delete host:src/dir /dest

BATCH MODE
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 op-
tion causes the rsync client to store in a "batch file" all the information needed to re-
peat this operation against other, identical destination trees.

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 trans-
port 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.

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 up-
dates the destination tree using the information stored in the batch file.

For your convenience, a script file is also created when the write-batch option is used:
it will be named the same as the batch file with ".sh" appended. This script file con-
tains a command-line suitable for updating a destination tree using the associated batch
file. It can be executed using a Bourne (or Bourne-like) shell, optionally passing in an
alternate destination tree pathname which is then used instead of the original destination
path. This is useful when the destination tree path on the current host differs from the
one used to create the batch file.

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 informa-
tion 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 be-
tween the two examples reveals some of the flexibility you have in how you deal with
batches:

o 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.

o 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.

o 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=-" op-
tion).

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 a warning
(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 gen-
erate 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. See also the --protocol option for
a way to have the creating rsync generate a batch file that an older rsync can understand.
(Note that batch files changed format in version 2.6.3, so mixing versions older than that
with newer versions will not work.)

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 --filter/--include/--exclude options are not needed un-
less one of the --delete options is specified.

The code that creates the BATCH.sh file transforms any filter/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 di-
rectory.

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 destina-
tion. Note that --archive implies --links.

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

Rsync can also distinguish "safe" and "unsafe" symbolic links. An example where this
might be used is a web site mirror that wishes to ensure that the rsync module that is
copied 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.
(Note that you must specify --links for --safe-links to have any effect.)

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.

Here's a summary of how the symlink options are interpreted. The list is in order of
precedence, so if your combination of options isn't mentioned, use the first line that is
a complete subset of your options:

--copy-links
Turn all symlinks into normal files (leaving no symlinks for any other options to
affect).

--links --copy-unsafe-links
Turn all unsafe symlinks into files and duplicate all safe symlinks.

--copy-unsafe-links
Turn all unsafe symlinks into files, noisily skip all safe symlinks.

--links --safe-links
Duplicate safe symlinks and skip unsafe ones.

--links
Duplicate all symlinks.

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 filter patterns, then try specifying the -vv option.
At this level of verbosity rsync will show why each individual file is included or ex-
cluded.

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

6 Daemon unable to append to log-file

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

25 The --max-delete limit stopped deletions

30 Timeout in data send/receive

35 Timeout waiting for daemon connection

ENVIRONMENT VARIABLES
CVSIGNORE
The CVSIGNORE environment variable supplements any ignore patterns in .cvsignore
files. See the --cvs-exclude option for more details.

RSYNC_ICONV
Specify a default --iconv setting using this environment variable. (First supported
in 3.0.0.)

RSYNC_OLD_ARGS
Specify a "1" if you want the --old-args option to be enabled by default, a "2" (or
more) if you want it to be enabled in the option-repeated state, or a "0" to make
sure that it is disabled by default. When this environment variable is set to a
non-zero value, it supersedes the RSYNC_PROTECT_ARGS variable.

This variable is ignored if --old-args, --no-old-args, or --protect-args is speci-
fied on the command line.

RSYNC_PROTECT_ARGS
Specify a non-zero numeric value if you want the --protect-args option to be en-
abled by default, or a zero value to make sure that it is disabled by default.
(First supported in 3.1.0.)

This variable is ignored if --protect-args, --no-protect-args, or --old-args is
specified on the command line.

This variable is ignored if RSYNC_OLD_ARGS is set to a non-zero value.

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 connecting 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 remote shell transport such as ssh; to learn how to do
that, consult the remote shell's documentation.

USER or LOGNAME
The USER or LOGNAME environment variables are used to determine the default user-
name sent to an rsync daemon. If neither is set, the username defaults to "no-
body".

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

FILES
/etc/rsyncd.conf or rsyncd.conf