This is a bash-inspired shell application that offers multiprocessing support. When you type in a command (in response to the shell prompt), the shell creates a child process that executes the command that was entered. The shell has 3 built-in commands:

1. jobs: print the list of processes that are currently running in the background
2. kill <PID>: kill the child process with the specified PID (if it exists)
3. exit: quit the shell

When a non-built-in command is entered, the shell creates a new child process which invokes the specified executable program. These processes can be specified to run in the foreground or in the background. Non-built-in commands should contain the full path to the executable file (e.g., /bin/ls rather than just ls) and may contain an arbitrary number of command-line options (e.g., /bin/ls -l -r). To indicate that a command should be executed as a background process, include the ampersand (&) character at the end of the command (e.g., /bin/sleep 10 &).

Every time the shell receives a new command, it scans the list of background processes. If any of these processes have completed, it updates the list and prints: <PID> finished with exit code <STATUS>.

To compile the shell, run: make. To start the shell, run: ./shell.