diff --git a/document/linux/config/bash/module/own.sh b/document/linux/config/bash/module/own.sh
index 0e814d1..2200f1b 100644
--- a/document/linux/config/bash/module/own.sh
+++ b/document/linux/config/bash/module/own.sh
@@ -1,24 +1,24 @@
 # change file ownership to specified user id and restrict access to him.
 own() 
 {
-  local file="$2"
-  local user="$1"
+  local file="${2}"
+  local user="${1}"
 
   # default to current dir.
-  if [ "$file" = "" ]; then
+  if [ "${file}" = "" ]; then
     file='.'
   fi
 
   # default to current user.
-  if [ "$user" = "" ]; then
-    user="$UID"
+  if [ "${user}" = "" ]; then
+    user="${UID}"
   fi
 
   # set ownership.
-  chown "$user":"$user" -R "$file" &> /dev/null
+  chown "${user}":"${user}" -R "${file}" &> /dev/null
 
   # remove access from group and others.
-  chmod -077 -R "$file"
+  chmod -077 -R "${file}"
 }
 
 # autocomplete.