more safely remove for move away functionality

usr/share/rear/conf/default.conf

@@ -802,13 +802,19 @@ readonly BACKUP_RESTORE_MOVE_AWAY_DIRECTORY="$VAR_DIR/moved_away_after_backup_re
 # so that it can be modified as needed by the scripts.
 # The items in the BACKUP_RESTORE_MOVE_AWAY_FILES list do not need to be only files.
 # Also a whole directory tree can be moved away (automatically recursively).
+# If an item in BACKUP_RESTORE_MOVE_AWAY_FILES is a directory only its content
+# is (recursively) removed but the original (empty) directory is kept because
+# the empty directory alone should not cause issues and usually only the content
+# is what results wrong/outdated content that conflicts with the actual system
+# or what is no longer needed after system recovery (e.g. content in /var/tmp
+# is probably no longer needed but the /var/tmp directory is still needed).
 # Already existing stuff in the BACKUP_RESTORE_MOVE_AWAY_DIRECTORY that would be (partially)
 # overwritten by the items in the BACKUP_RESTORE_MOVE_AWAY_FILES list is removed before
 # (because such stuff is considered as outdated leftover e.g. from a previous recovery)
 # but already existing stuff in the BACKUP_RESTORE_MOVE_AWAY_DIRECTORY that is not
 # in the curent BACKUP_RESTORE_MOVE_AWAY_FILES list is kept.
 # Example:
-# Perhaps stuff in the /var/tmp directory is not needed after a system recovery
+# Probably stuff in the /var/tmp directory is not needed after a system recovery
 # and /etc/udev/rules.d/70-persistent-net.rules is created and maintained
 # by systemd/udev (see https://github.com/rear/rear/issues/770):
 # BACKUP_RESTORE_MOVE_AWAY_FILES=( /var/tmp /etc/udev/rules.d/70-persistent-net.rules )

usr/share/rear/restore/default/99_move_away_restored_files.sh

@@ -57,8 +57,22 @@ for dummy in "once" ; do
         # but keep already existing stuff in the move away directory
         # that is not in the curent BACKUP_RESTORE_MOVE_AWAY_FILES list:
         rm -rf $move_away_dir/$file_relative
-        # Only if the copy was successful remove the original file or directory:
-        cp -a --parents $file_relative $move_away_dir && rm -rf $file_relative
+        # Copy the file or directory:
+        cp -a --parents $file_relative $move_away_dir || continue
+        # Only if the copy was successful remove the original file or directory content
+        # but keep the original (empty) directory (for the reason see default.conf):
+        if test -d $file_relative ; then
+            # remove all files in the directory other than '.' and '..'
+            # (avoids scaring stderr message: "rm: refusing to remove '.' or '..' directory")
+            # * matches non-dot-files
+            # .[!.]* matches dot-files except '.' and dot-dot-files
+            # ..?* matches dot-dot-files (also dot-dot-...-dot-files) except '..'
+            # If all patterns match nothing the nullglob setting in rear let it expand to empty
+            # which is o.k. because 'rm -f' does not care about non-existent arguments:
+            rm -rf $file_relative/* $file_relative/.[!.]* $file_relative/..?*
+        else
+            rm -rf $file_relative
+        fi
     done
 done
 # Go back from the recovery system root directory: