How To Run:

Run the following commands in the shell:
$ make
$ ./a.out

NOTE: This shell's home directory is set as the directory from where the executable is invoked.

Manually implemented commands:

1. echo - similar to bash's "echo" command
2. pwd - similar to bash's "pwd" command
3. cd (flags: ~, -, ., ..) - similar to bash's "cd" command
4. ls (flags: -a, -l) - similar to bash's "ls" command
5. jobs - gives info on all background jobs
6. setenv <var> <value> - creates environment variable var and stores value in it
7. unsetenv <var> - destroys environment variable var
8. bg - resumes a suspended background job in the background itself
9. nightswatch - similar to bash's "watch" command
10. newborn - prints pid of most recently created process
11. interrupt - prints CPU interrupt info
12. kjob <job number> <signal number> - sends signal corresponding to signal number to job corresponding to job number
13. overkill - kill all background jobs
14. quit - terminate shell

NOTE: Ctrl-C terminates the current running foreground command/job and Ctrl-Z suspends it and sends it to the background. Can use Ctrl-D to terminate shell.