1 files changed, 1 insertions, 1 deletions
diff --git a/src/fd.sh b/src/fd.sh
index c52efec..345eee6 100644
--- a/src/fd.sh
+++ b/src/fd.sh
@@ -60,7 +60,7 @@ fopen()
 			fd=${i}
 			break
 		fi
-		i=$(($i + 1))
+		i=$((${i} + 1))
 	done
 	if [ "x${fd:+set}" != 'xset' ]; then
 		error "$(get_msg 'emfile')"