diff --git a/src/aws/dependencies/utilitiyFunction.sh b/src/aws/dependencies/utilitiyFunction.sh
index 2a00353..1b2d7aa 100644
--- a/src/aws/dependencies/utilitiyFunction.sh
+++ b/src/aws/dependencies/utilitiyFunction.sh
@@ -1,4 +1,3 @@
-
 # Filters instances from JSON data based on the tag "Class" with a value of "treehouses".
 # Expects JSON data in the format returned by the AWS CLI command 'describe-instances'.
 # Uses 'jq' to parse and filter the data.
@@ -9,43 +8,90 @@ function filterInstancesByTag {
   echo "$jsonData" | jq '[.Reservations[].Instances[] | select(.Tags[]? | .Key=="Class" and .Value=="treehouses")]'
 }
 
-function waitForOutput(){
-    local cmd=$1
-    local result=$(eval $cmd)
-    while [ -z "$result" ] || [ "$result" == "null" ]
-    do
-        sleep 5
-        result=$(eval $cmd)
-    done
-    echo $result
+function waitForOutput() {
+  local cmd=$1
+  local result=$(eval $cmd)
+  while [ -z "$result" ] || [ "$result" == "null" ]; do
+    sleep 5
+    result=$(eval $cmd)
+  done
+  echo $result
 }
 
 setBalloonName() {
-    if [ -z "$1" ]; then
-        echo "luftballon"
-    else
-        echo "$1"
-    fi
+  if [ -z "$1" ]; then
+    echo "luftballon"
+  else
+    echo "$1"
+  fi
 }
 
 function makePortArray {
-    local portString="$1"
-    local -a portArray
+  local portString="$1"
+  local -a portArray
 
-    IFS=',' read -ra pairs <<< "$portString"
+  IFS=',' read -ra pairs <<<"$portString"
 
-    for pair in "${pairs[@]}"; do
-        IFS=':' read -ra ports <<< "$pair"
-        for port in "${ports[@]}"; do
-            portArray+=("$port")
-        done
+  for pair in "${pairs[@]}"; do
+    IFS=':' read -ra ports <<<"$pair"
+    for port in "${ports[@]}"; do
+      portArray+=("$port")
     done
+  done
+
+  echo "${portArray[@]}"
+}
 
-    echo "${portArray[@]}"
+function getState() {
+  local instanceId=$1
+  local state=$(aws ec2 describe-instances --instance-ids $instanceId | jq '.Reservations[].Instances[].State.Name')
+  echo $state
 }
 
-function getState(){
-    local instanceId=$1
-    local state=$(aws ec2 describe-instances --instance-ids $instanceId | jq '.Reservations[].Instances[].State.Name')
-    echo $state
+# Function: waitForConditionalOutput
+# Description: Waits for a command to produce a specific result based on the specified mode.
+# Parameters:
+#   $1 - The command to execute
+#   $2 - The target value to compare against
+#   $3 - The mode of operation: 'match' or 'different'
+#        'match': Waits for the result to match the target value
+#        'different': Waits for the result to be different from the target value
+# Returns:
+#   0 - If the desired condition is met within the max attempts
+#   1 - If the desired condition is not met within the max attempts
+
+function waitForConditionalOutput() {
+  local cmd=$1
+  local targetValue=$2
+  local mode=$3
+  local maxAttempts=3
+  local attempt=0
+
+  # Validate mode
+  if [[ "$mode" != "match" && "$mode" != "different" ]]; then
+    echo "Error: Invalid mode. Use 'match' or 'different'."
+    return 1
+  fi
+
+  while [ $attempt -lt $maxAttempts ]; do
+    local result=$(eval $cmd)
+    if [ "$mode" == "match" ]; then
+      # Wait for the result to match the target value
+      if [ "$result" == "$targetValue" ]; then
+        echo $result
+        return 0
+      fi
+    elif [ "$mode" == "different" ]; then
+      # Wait for the result to be different from the target value
+      if [ "$result" != "$targetValue" ]; then
+        echo $result
+        return 0
+      fi
+    fi
+    attempt=$((attempt + 1))
+    sleep 10
+  done
+
+  echo "Error: Failed to meet the condition after $maxAttempts attempts."
+  return 1
 }
diff --git a/src/aws/start.sh b/src/aws/start.sh
index 76cec03..0933a39 100644
--- a/src/aws/start.sh
+++ b/src/aws/start.sh
@@ -3,49 +3,48 @@
 #BASE=$HOME
 BASE=/home/pi
 
-function start(){
-    balloonName=$(setBalloonName "$1")
+function start() {
+  balloonName=$(setBalloonName "$1")
 
-    if ! isBalloonNameValid "$balloonName"; then
-        echo "Please provide a valid balloon name"
-        exit 1
-    fi
+  if ! isBalloonNameValid "$balloonName"; then
+    echo "Please provide a valid balloon name"
+    exit 1
+  fi
 
-    instanceId=$(getValueByAttribute $balloonName instanceId)
+  instanceId=$(getValueByAttribute "$balloonName" instanceId)
 
-    if [ "$instanceId" = "null" ]; then
-        echo "$balloonName does not exist"
-        exit 1
-    fi
+  if [ "$instanceId" = "null" ]; then
+    echo "$balloonName does not exist"
+    exit 1
+  fi
 
-    oldPublicIp=$(getValueByAttribute $balloonName publicIp)
+  # oldPublicIp=$(getValueByAttribute "$balloonName" publicIp)
 
-    state=$(getState $instanceId)
+  state=$(waitForConditionalOutput "getState $instanceId" "\"stopping\"" "different")
+  if [ $? -ne 0 ]; then
+    echo "Wait for starting on start command until instance is stopped."
+    exit 1
+  fi
 
-    if [ "$state" == "\"running\"" ]; then
-        echo "The instance is already running"
-        exit 0
-    fi
+  if [ "$state" == "\"running\"" ]; then
+    echo "The instance is already running"
+    exit 0
+  fi
 
-    if [ "$state" == "\"stopping\"" ]; then
-        echo "The instance is stopping"
-        exit 1
-    fi
+  aws ec2 start-instances --instance-ids "$instanceId"
 
-    aws ec2 start-instances --instance-ids $instanceId
+  echo "get the new ip address. The procedure might take time for a while"
+  publicIp=$(waitForOutput "getLatestIpAddress $instanceId")
 
-    echo "get the new ip address. The procedure might take time for a while"
-    publicIp=$(waitForOutput "getLatestIpAddress $instanceId")
+  # portConfigArray=$(getArrayValueAsStringByKey "$instanceName" tcpPortArray)
 
-    portConfigArray=$(getArrayValueAsStringByKey $instanceName tcpPortArray)
+  echo "the new ip address is $publicIp"
+  updateIPAddress "$balloonName" "$publicIp"
 
-    echo "the new ip address is $publicIp"
-    updateIPAddress $balloonName $publicIp
+  closeSSHTunnel
+  echo "remove old ssh tunnel settings"
+  sleep 5
 
-    closeSSHTunnel
-    echo "remove old ssh tunnel settings"
-    sleep 5
-
-    restartSSHTunnel $balloonName $publicIp
-    echo "open new ssh tunnel"
+  restartSSHTunnel "$balloonName" "$publicIp"
+  echo "open new ssh tunnel"
 }
diff --git a/src/aws/up.sh b/src/aws/up.sh
index e31d8ec..5cc9664 100644
--- a/src/aws/up.sh
+++ b/src/aws/up.sh
@@ -158,7 +158,6 @@ function up {
     echo "Success to add ssh key: $importedKeyName"
   else
     echo "The key pair $keyname already exists. Please use another key name."
-    importedKeyName=$keyname
   fi
 
   if ! checkSecurityGroup; then
@@ -169,44 +168,54 @@ function up {
     echo "Security Group already exists."
   fi
 
-  instanceId=$(checkInstance)
-  if [ -z "$instanceId" ]; then
-    instanceState=""
+  createAndTagInstance() {
     instanceId=$(createEc2 | getValueByKeyword InstanceId)
     echo "Creating and running EC2 instance..."
     echo "Instance id is $instanceId"
+
     aws ec2 create-tags --resources $instanceId --tags Key=Name,Value=$instanceName
     aws ec2 create-tags --resources $instanceId --tags Key=Class,Value=treehouses
+
     publicIp=$(waitForOutput "getLatestIpAddress $instanceId")
     echo "Public IP Address is $publicIp"
     echo "Will open ssh tunnel soon"
+
     isOpen=$(waitForOutput "ssh-keyscan -H $publicIp | grep ecdsa-sha2-nistp256")
     echo "Opened ssh tunnel"
+
     openSSHTunnel $instanceName $publicIp $portConfigArray
-    storeConfigIntoTreehousesConfigAsStringfiedJson $instanceName $importedKeyName $instanceId $publicIp $groupNameaws ec2 create-tags --resources $instanceId --tags Key=Class,Value=treehouses
+    storeConfigIntoTreehousesConfigAsStringfiedJson $instanceName $importedKeyName $instanceId $publicIp $groupName
+  }
+
+  instanceId=$(checkInstance)
+  if [ -z "$instanceId" ]; then
+    createAndTagInstance
+  else
+    instanceState=$(waitForConditionalOutput "checkInstanceState $instanceId" "\"stopping\"" "different")
+    if [ $? -ne 0 ]; then
+      echo "Wait for starting on start command until instance is stopped."
+      exit 1
+    fi
+    echo "Success to add ssh key: $importedKeyName"
   else
-    instanceState=$(checkInstanceState $instanceId)
-    if [ "$instanceState" = "running" ]; then
+    echo "The key pair $keyname already exists. Please use another key name."
+    importedKeyName=$keyname
+  fi
+
+    case "$instanceState" in
+    "running")
       echo "EC2 instance is already running."
-    elif [ "$instanceState" = "stopped" ]; then
+      ;;
+    "stopped")
       echo "Starting stopped EC2 instance..."
       start $instanceName
-    elif [ "$instanceState" = "terminated" ]; then
-      instanceState=""
-      instanceId=$(createEc2 | getValueByKeyword InstanceId)
-      echo "Creating and running EC2 instance..."
-      echo "Instance id is $instanceId"
-      aws ec2 create-tags --resources $instanceId --tags Key=Name,Value=$instanceName
-      aws ec2 create-tags --resources $instanceId --tags Key=Class,Value=treehouses
-      publicIp=$(waitForOutput "getLatestIpAddress $instanceId")
-      echo "Public IP Address is $publicIp"
-      echo "Will open ssh tunnel soon"
-      isOpen=$(waitForOutput "ssh-keyscan -H $publicIp | grep ecdsa-sha2-nistp256")
-      echo "Opened ssh tunnel"
-      openSSHTunnel $instanceName $publicIp $portConfigArray
-      storeConfigIntoTreehousesConfigAsStringfiedJson $instanceName $importedKeyName $instanceId $publicIp $groupNameaws ec2 create-tags --resources $instanceId --tags Key=Class,Value=treehouses
-    else
+      ;;
+    "terminated")
+      createAndTagInstance
+      ;;
+    *)
       echo "EC2 instance is in state: $instanceState."
-    fi
+      ;;
+    esac
   fi
 }