Can some one please explain in an easy to understand way the concept of controlling terminal in unix  and unix like systems ? Is it related to a session ? If yes, then how ?
Concept of controlling terminal in Unix
terminal;session;job control;controlling terminal
There is a process group leader - sort of like the head process - that owns the terminal, /dev/tty.  A process group can be one or many processes.The stty command changes and displays terminal settings.  If you are actually going to use UNIX seriously consider finding a copy of Stevens 'Advanced Programming in the UNIX Environment'.Terminals have a lot of heavy baggage from the 1970's.   You will spot that right away.  Most of those odd settings can be ignored except for special things like UNIX system consoles.