diff --git a/README.md b/README.md
index ead10a8..fd91500 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,12 @@
 
 Command Line Scripts for ZJU (VPN / WLAN / DNS)
 
+## Require
+
+```bash
+sudo apt-get install curl
+```
+
 ## TODO
 
 - zjunet vpn
@@ -25,3 +31,5 @@ Command Line Scripts for ZJU (VPN / WLAN / DNS)
 ## Links
 
 - [Array in unix Bourne Shell](http://unix.stackexchange.com/questions/137566/array-in-unix-bourne-shell)
+
+- [How do you tell if a string contains another string in Unix shell scripting?](http://stackoverflow.com/questions/2829613/how-do-you-tell-if-a-string-contains-another-string-in-unix-shell-scripting)
diff --git a/user.sh b/user.sh
index 1201e2c..46c44c6 100755
--- a/user.sh
+++ b/user.sh
@@ -22,6 +22,10 @@
 DIR="$HOME/.zjunet"
 mkdir -p $DIR
 
+getall() {
+    ls -1A $DIR | xargs | tr "\n" " "
+}
+
 # dispatch
 case "$1" in
 
@@ -38,7 +42,8 @@ case "$1" in
         ;;
 
     delete)
-        read -p "USERNAME: " USERNAME
+        USERS=$(getall)
+        read -p "Delete User [ ${USERS}]: " USERNAME
         rm -i "$DIR/${USERNAME}"
         ;;
 
@@ -55,7 +60,7 @@ case "$1" in
             exit 1
         else
             if [ "${COUNT}" -gt "1" ]; then
-                USERS=$(ls -1A $DIR | xargs | tr "\n" " ")
+                USERS=$(getall)
                 read -p "Choose User [ ${USERS}]: " USERNAME
             else
                 USERNAME=$(ls -1 $DIR | head -n1)
@@ -67,7 +72,7 @@ case "$1" in
     # Get all users
     # @private
     getall)
-        ls -1A $DIR | xargs | tr "\n" " "
+        getall
         ;;
 
     # @private
diff --git a/wlan.sh b/wlan.sh
index 14a292b..c9e5516 100755
--- a/wlan.sh
+++ b/wlan.sh
@@ -25,10 +25,16 @@ logout() {
 
     echo "Logout: ${USERNAME}"
     RESPONSE=$(curl "https://net.zju.edu.cn/rad_online.php" -H "Content-Type: application/x-www-form-urlencoded" -d "action=auto_dm&username=${USERNAME}&password=${PASSWORD}" -s)
-    if [[ "${RESPONSE}" != "ok" ]]; then
-        echo "${RESPONSE}" >&2
-        exit 1
-    fi
+
+    case "${RESPONSE}" in
+        *ok*)
+            echo "Logout: success."
+            ;;
+        *)
+            echo "Logout: ${RESPONSE}."
+            exit 1;
+            ;;
+    esac
 }
 
 login() {
@@ -39,19 +45,25 @@ login() {
 
     echo "Login: ${USERNAME}"
     RESPONSE=$(curl "https://net.zju.edu.cn/cgi-bin/srun_portal" -H "Content-Type: application/x-www-form-urlencoded" -d "action=login&username=${USERNAME}&password=${PASSWORD}&ac_id=3&type=1&is_ldap=1&local_auth=1" -s)
-    if [[ "${RESPONSE}" = *"help.html"* || "${response}" = *"login_ok"* ]]; then
-        echo "Login successful"
-    else
-        echo "${RESPONSE}" >&2
-        exit 1
-    fi    
+
+    case "${RESPONSE}" in
+        *help.html*)
+            echo "Login: success."
+            ;;
+        *login_ok*)
+            echo "Login: success."
+            ;;
+        *)
+            echo "Login: ${RESPONSE}" >&2
+            exit 1
+            ;;
+    esac
 }
 
 BASEDIR=$(dirname $0)
 USER="${BASEDIR}/user.sh"
 
 USERNAME=$($USER get)
-
 PASSWORD=$($USER getpwd $USERNAME)
 
 case "$1" in
@@ -61,4 +73,10 @@ case "$1" in
     logout)
         logout $USERNAME $PASSWORD
         ;;
+    *)
+        echo "Usage: "
+        echo "    zjunet wlan login"
+        echo "    zjunet wlan logout"
+        ;;
 esac
+
diff --git a/zjunet.sh b/zjunet.sh
index ba14981..c269b91 100755
--- a/zjunet.sh
+++ b/zjunet.sh
@@ -28,10 +28,10 @@ case "$1" in
         ip route show 0/0 | cut -d " " -f 3
         ;;
     wlan)
-        "${BASEDIR}/wlan.sh"
+        "${BASEDIR}/wlan.sh" $2
         ;;
     vpn)
-        "${BASEDIR}/vpn.sh"
+        "${BASEDIR}/vpn.sh" $2
         ;;
     dns)
         "${BASEDIR}/dns.sh"