To simplify your life as a teacher and as the answers will not be exactly the same in each `mystery` folder, you need to write a `teacher.sh` file that does the following:
- step 1, it isolates, into an environment variable and through a similar command that you used to find it, the number (**and only the number**) of the key interview that helped solved the mystery (Unlike the interview number, the path will not change across the `mystery` folders that will be tested, hence the command to find the interview is the same across all the `mystery` folders that will be tested).
- step 2, it prints the newly created environment variable.
- step 3, it prints what the interview contains.
- step 4, it prints the content of the environment variable MAIN_SUSPECT.