I am making an exception and made a sample solution to Lab 4 available.
We have discovered errors with the grades and marks given out to Lab 4. This means that the email you received may contain incorrect marks and comments. IMPORTANT: if you receive a full marks, you should still check your solution against the sample posted — because your solution could still be wrong or incomplete.
I apologize for the errors, and I am regrading all of your Lab 4 submissions to make this right.
There is no specific question about shell and Lab 4 in the midterm, in case you are wondering. But you should still get familiarize with the system calls involved, including fork, wait, exec, exit, signal, and kill.