-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 bf(--backup), since rsync is smart enough to use the backup file as the
-basis file for the transfer.
+dit(bf(--inplace)) This option changes how rsync transfers a file when the
+file's 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: (1) in-use binaries cannot be updated (either the
+OS will prevent this from happening, or binaries that attempt to swap-in
+their data will misbehave or crash), (2) the file's data will be in an
+inconsistent state during the transfer, (3) a file's data may be left in an
+inconsistent state after the transfer if the transfer is interrupted or if
+an update fails, (4) a file that does not have write permissions can not be
+updated, and (5) 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 position later in the file (one exception to this is if you
+combine this option with bf(--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.