diff --git a/cd.sh b/cd.sh
index 8c7e9c9..bb50c68 100644
--- a/cd.sh
+++ b/cd.sh
@@ -626,10 +626,10 @@ local variable="${1}"
 }
 
 cd_grep_os () {
-local variable="${1}"
-    if [ "${variable}" ] ; then
-        grep "^${variable}=" "/etc/os-release" \
-        | sed "s|^${variable}=||" \
+    cd_grep_os__variable="${1}"
+    if [ "${cd_grep_os__variable}" ] ; then
+        grep "^${cd_grep_os__variable}=" "/etc/os-release" \
+        | sed "s|^${cd_grep_os__variable}=||" \
         | sed "s|^\"\(.*\)\"$|\1|"
     fi
 }