A Simple Shell This exercise can be solved on any UNIX system. Starting with the code in Section 2.4, design and implement a simple, interactive shell pro- gram that prompts the user for a command, parses the command, and then executes it with a child process. In your solution you are required to use execv() instead of execvp(), which means that you will have to read the PATH environment variable, then search each directory in the PATH for the command file name that appears on the command line