-backup suffix used with the -b option. The default is a ~.
-
-dit(bf(-u, --update)) This forces rsync to skip any files for which the
-destination file already exists and has a date later than the source
-file.
-
-dit(bf(-l, --links)) This tells rsync to recreate symbolic links on the
-remote system to be the same as the local system. Without this
-option, all symbolic links are skipped.
-
-dit(bf(-L, --copy-links)) This tells rsync to treat symbolic links just
-like ordinary files.
-
-dit(bf(--copy-unsafe-links)) This tells rsync to treat symbolic links that
-point outside the source tree like ordinary files. Absolute symlinks are
-also treated like ordinary files, and so are any symlinks in the source
-path itself when --relative is used.
+backup suffix used with the --backup (-b) option. The default suffix is a ~
+if no --backup-dir was specified, otherwise it is an empty string.
+
+dit(bf(-u, --update)) This forces rsync to skip any files which exist on
+the destination and have a modified time that is newer than the source
+file. (If an existing destination file has a modify time equal to the
+source file's, it will be updated if the sizes are different.)
+
+In the current implementation of --update, a difference of file format
+between the sender and receiver is always
+considered to be important enough for an update, no matter what date
+is on the objects. In other words, if the source has a directory or a
+symlink where the destination has a file, the transfer would occur
+regardless of the timestamps. This might change in the future (feel
+free to comment on this on the mailing list if you have an opinion).
+
+dit(bf(--inplace)) This causes rsync not to create a new copy of the file
+and then move it into place. Instead rsync will overwrite the existing
+file, meaning that the rsync algorithm can't accomplish the full amount of
+network reduction it might be able to otherwise (since it does not yet try
+to sort data matches). One exception to this is if you combine the option
+with --backup, since rsync is smart enough to use the backup file as the
+basis file for the transfer.
+
+This option is useful for transfer of large files with block-based changes
+or appended data, and also on systems that are disk bound, not network
+bound.
+
+The option implies --partial (since an interrupted transfer does not delete
+the file), but conflicts with --partial-dir. Prior to rsync 2.6.4
+--inplace was also incompatible with --compare-dest, --copy-dest, and
+--link-dest.
+
+WARNING: The file's data will be in an inconsistent state during the
+transfer (and possibly afterward if the transfer gets interrupted), so you
+should not use this option to update files that are in use. Also note that
+rsync will be unable to update a file in-place that is not writable by the
+receiving user.
+
+dit(bf(-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 was specified on the command-line as either "." or a
+name with a trailing slash (e.g. "foo/"). Without this option or the
+--recursive option, rsync will skip all directories it encounters (and
+output a message to that effect for each one).
+
+dit(bf(-l, --links)) When symlinks are encountered, recreate the
+symlink on the destination.
+
+dit(bf(-L, --copy-links)) When symlinks are encountered, the file that
+they point to (the referent) is copied, rather than the symlink. In older
+versions of rsync, this option also had the side-effect of telling the
+receiving side to follow symlinks, such as symlinks to directories. In a
+modern rsync such as this one, you'll need to specify --keep-dirlinks (-K)
+to get this extra behavior. The only exception is when sending files to
+an rsync that is too old to understand -K -- in that case, the -L option
+will still have the side-effect of -K on that older receiving rsync.
+
+dit(bf(--copy-unsafe-links)) This tells rsync to copy the referent of
+symbolic links that point outside the copied tree. Absolute symlinks
+are also treated like ordinary files, and so are any symlinks in the
+source path itself when --relative is used.