Command Retrieve Exit Programs Can Run After Command Completion

There are many places in the operating systems where it might be desirable for you (or third-party application providers) to extend the functionality of what the operating system does. In order to provide this extensibility, many operating systems provide the support for invoking programs. On i, these are called exits or exit points. The exit points are those predefined interfaces where your program can get control An exit program is the program you write that will get control from operating system functions at those predefined points.