The original tar file is shlab-handout.tar and the writeup is shlab.pdf. My solution is in shlab-handout/.

Reading 8.1 - 8.8 of CSAPP: 3e can be very helpful.
Make sure you understand the content in the slides very carefully, especially 15-ecf-signals.pdf.
Read the writeup very carefully.

This lab is not too hard. A lot of hints are provided:

1. Some snippets in lecture slide are very similar to the code for the lab;
2. The writeup provides strategies for most of the tricky parts in the lab, so make sure you read the write up very carefully;
3. Make good use of man page;
4. This page is very useful for solving trace08.txt: https://stackoverflow.com/questions/28209525/how-would-i-check-for-child-process-changing-state-but-not-terminating