This is a skeleton for CS 111 Lab 1.

Replace this README file with notes on your implementation.
Mentions any special features or limitations.

This project is done by Baixiao
     	     	    and Jiayi 
Answers:
1: absolute time is not necessary in non-decreasing order. 
For example command sort dictionary.txt; echo a
if the dictionary.txt is too big, echo may finish before
sorting can finish.
2:Yes, for example a sequence command a;b
a and b can be executed at the same time, so the real time
will appear to be less than total user and system time of
a and b.
3.No, if real time is negative, process is completed before
it starts, which is impossible. For user time and system 
time, they represents the usage of CPU, and they are non-
negative.
4.All parent processes wait for its children, no way the
output will be interleaved.