finding login time and idle time,..etc from a list of users
 

how to accept the list of users and if they are currently logged in, list the current login time and last logging time, idle time, count of the number of multiple logins (do not allow access to home directory if the count >=3), jumble their names (as 5th char to end and add the first four characters), of all these users in alphabetical order. Else display the message that they have not logged in?

So to clarify your above statement, you are attempting to find a way to audit login events and attempts on your linux box?

Hi,

Smells like homework to me!