+
+ if [ -f "$DESTINATION" ] && [ $# = 3 ] && [ -n "$3" ]; then
+ # Keep existing file if checksum matches.
+ local EXISTING_CHECKSUM
+ EXISTING_CHECKSUM=$(sha256sum "$DESTINATION" | cut -f 1 -d ' ')
+ if [ "$EXISTING_CHECKSUM" = "$3" ]; then return; fi
+ fi
+