tion file (if combined with --inplace) or for testing the  check‐
              sum‐based update algorithm.

              See also the --whole‐file option.

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

              The checksum options that you may be able to use are:

              o      auto (the default automatic choice)

              o      xxh128

              o      xxh3

              o      xxh64 (aka xxhash)

              o      md5

              o      md4

              o      sha1

              o      none

              Run rsync --version to see the  default  checksum  list  compiled
              into your version (which may differ from the list above).

              If "none" is specified for the first (or only) name, the --whole‐
              file  option  is  forced  on and no checksum verification is per‐
              formed on the transferred data.  If "none" is specified  for  the
              second (or only) name, the --checksum option cannot be used.

              The "auto" option is the default, where rsync bases its algorithm
              choice on a negotiation between the client and the server as fol‐
              lows:

              When both sides of the transfer are at least 3.2.0, rsync chooses
              the  first algorithm in the client’s list of choices that is also
              in the server’s list of choices.  If no common checksum choice is
              found, rsync exits with an error.  If the remote rsync is too old
              to support checksum negotiation, a value is chosen based  on  the
              protocol  version  (which chooses between MD5 and various flavors
              of MD4 based on protocol age).

              The default order can be customized by  setting  the  environment
              variable RSYNC_CHECKSUM_LIST to a space‐separated list of accept‐
              able  checksum names.  If the string contains a "&" character, it
              is separated into the "client string & server string",  otherwise
              the  same  string applies to both.  If the string (or string por‐
              tion) contains no non‐whitespace characters, the default checksum
              list is used.  This method does not  allow  you  to  specify  the
              transfer  checksum separately from the pre‐transfer checksum, and
              it discards "auto" and all unknown checksum names.  A  list  with
              only invalid names results in a failed negotiation.

              The  use  of the --checksum‐choice option overrides this environ‐
              ment list.

       --one‐file‐system, -x
              This tells rsync to avoid crossing a filesystem boundary when re‐
              cursing.  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 specified, 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  directo‐
              ries 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 di‐
              rectory are inaccessible).

              If rsync has been