BashScripting

1-How to read and take input from user
1-1-How to make entry of password without showing it on screen
1-2-How to take multiple input and save it as an array
1-3 default variable "REPLY"
1-4 How to find wether file exist or not! wether file is normal file or block special file use of all other operators related with file
1-5 Making and checking conditon to make file and how to append file or overwrite new files through any existing files\