-If you are deleting files on the destination and your partial-dir is
-inside the destination hierarchy, make sure you specify an exclude to
-prevent the partial file from being deleted (it could get deleted at the
-end of the transfer when using --delete-after, or at the beginning of the
-transfer when using --delete). E.g. "--exclude=.rsync-partial/".
-
-IMPORTANT: the --partial-dir should not be writable by other users to
-avoid a security risk. E.g. AVOID "/tmp".
+If the partial-dir value is not an absolute path, rsync will also add an
+--exclude of this value at the end of all your existing excludes. This
+will prevent partial-dir files from being transferred and also prevent the
+untimely deletion of partial-dir items on the receiving side. An example:
+the above --partial-dir option would add an "--exclude=.rsync-partial/"
+rule at the end of any other include/exclude rules. Note that if you are
+supplying your own include/exclude rules, you may need to manually insert a
+rule for this directory exclusion somewhere higher up in the list so that
+it has a high enough priority to be effective (e.g., if your rules specify
+a trailing --exclude=* rule, the auto-added rule will be ineffective).
+
+IMPORTANT: the --partial-dir should not be writable by other users or it
+is a security risk. E.g. AVOID "/tmp".
+
+You can also set the partial-dir value the RSYNC_PARTIAL_DIR environment
+variable. Setting this in the environment does not force --partial to be
+enabled, but rather it effects where partial files go when --partial (or
+-P) is used. For instance, instead of specifying --partial-dir=.rsync-tmp
+along with --progress, you could set RSYNC_PARTIAL_DIR=.rsync-tmp in your
+environment and then just use the -P option to turn on the use of the
+.rsync-tmp dir for partial transfers. The only time the --partial option
+does not look for this environment value is when --inplace was also
+specified (since --inplace conflicts with --partial-dir).