fix debian-bash-upgrade

install.sh

@@ -40,8 +40,14 @@ function install_host() {
         echo "debian-bash has been deprecated!"
         echo "--------------------------------"
         
-        read -rn1 -p 'Would you like to migrate to the new project named `miaou-bash`, (yN)?' answer       
-        [[ -z "$PS1" ]] && answer='y'
+        if [[ -z "$PS1" ]]; then
+            read -rn1 -p 'Would you like to migrate to the new project named `miaou-bash`, (yN)?' answer       
+        else
+            echo "--------------------------------------------------"
+            echo "automatic migration from debian-bash to miaou-bash"
+            echo "--------------------------------------------------"            
+            answer='y'
+        fi
         
         if [[ "$answer" == 'y' ]];then
             pushd /tmp