This assignment is based on the programming “Project 1 - Unix Shell” in chapter 3 (P-15) of the textbook.
This project consists of designing a C/C++ program to serve as a shell interface that accepts user commands and then executes each command in a separate process. Your implementation will support input and output redirection, as well as pipes as a form of IPC between a pair of commands. Completing this project will involve using the UNIX fork(), exec(), wait(), dup2(), and pipe() system calls.
Required Output
Your program should always first print your names and a short description when it starts. You must submit your source code and Makefile so that we can compile your program with the make command.
Your program should implement I - IV parts of the project, namely:
1. Creating the child process and executing the command in the child
2. Providing a history feature
3. Adding support of input and output redirection
You may earn extra credits by implementing “Part V. Communication via a Pipe” in your program.
Attention:
Always check for potential errors of system calls in your code, which might lead to creating an infinite number of processes. For example, execvp() may fail if the command is unknown, which should result in an error message “command not found”. Monitor your processes and make sure all processes are terminated appropriately. We don't want to have hundreds of processes use up all the computer resources.
Use command “ps -afu your_user_name” to see the processes belonging to you and kill a process of yours using “kill -9 pid”, where pid is the id of the process.
Hint: You may use strtok function (strtok - C++ Reference (cplusplus.com)) to parse out the user command
