Problem
1. Redirect the output of fork.c to a file and explain the change in behavior.
2. Create a shell script that prints the values of HOME, PATH, MAIL, and TERM. Next, write a program that uses exec to run this script so that it prints null values for MAIL and TERM.
3. Explain which of these process attributes change with a fork and exec:
(i) PID,
(ii) PPID,
(iii) file descriptors,
(iv) standard I/O buffers.