Prompt IP address selection with 10 seconds timeout

ip.sh

#!/bin/bash

# Store all IP addresses of the machine into an array
mapfile -t ipArray < <(ip a | awk '$1 == "inet" {gsub(/\/.*$/, "", $2); print $2}')

# List out the IP addresses stored in the array 
echo "List of IP addresses"
for key in "${!ipArray[@]}"
do
    echo "$key: ${ipArray[$key]}"
done

# Set FRONTEND_IP to default 127.0.0.1
FRONTEND_IP=127.0.0.1
# Ask user to enter the desired IP address
read -t 10 -p "Select the IP address that you wish to use e.g. 1: " option
# If user does not enter within 10 seconds, set FRONTEND_IP to default 127.0.0.1
if [[ $? -gt 128 ]] ; then
    echo -e "\nTimeout. Setting IP address to default 127.0.0.1..."
else
    # Check if input only contain numbers
    if ! [[ "$option" =~ [^[:digit:]]+ ]] ; then
        # If user enters without any input, set FRONTEND_IP to default 127.0.0.1
        if [[ $option = "" ]]; then 
                echo "No input entered. Setting IP address to default 127.0.0.1..."
        # If user entered a valid number from the list, set FRONTEND_IP to the selected IP address 
        elif [[ -v "ipArray[option]" ]] ; then
                echo "Valid number selected. Setting IP address to ${ipArray[option]}..."
                FRONTEND_IP=${ipArray[option]}
        # If user entered a number not from the list, it is an invalid number. Set FRONTEND_IP to default 127.0.0.1
        else
                echo "Invalid number selected. Setting IP address to default 127.0.0.1..."
        fi
    #If input does not contain only numbers, it is an invalid input. Set FRONTEND_IP to default 127.0.0.1
    else
        echo "Invalid input. Setting IP address to default 127.0.0.1..."
    fi
fi
# Print the selected IP address
echo "Selected IP address = $FRONTEND_IP"