diff --git a/init.d/net.lo.in b/init.d/net.lo.in
index d647f319..21816576 100644
--- a/init.d/net.lo.in
+++ b/init.d/net.lo.in
@@ -144,7 +144,7 @@ _netmask2cidr()
 	local i= len=
 	local IFS=.
 	for i in $1; do
-		while [ i -ne 0 ]; do
+		while [ ${i} -ne 0 ]; do
 			: $(( len += i % 2 ))
 			: $(( i >>= 1 ))
 		done