README
Authors: 
Andy Huang       - UCLA ID: 503885009
Stephen Phillips - UCLA ID: 503888079

From Part 1A:
We don't have anything for special characters (e.g. \t, \n, etc.). We also 
consider apostrophes, quotations, grave accents as errors too. We do implement 
everything needed for test-p-ok.sh and gives appropriate errors and error 
messages including line numbers. There is some dummy code to allow the 
makefile compilation to work (gets rid of "argument not used" errors). The 
code does not change anything in the read-command.c file.

For Part 1B:
We have added the code to execute commands in the shell. Now it only does it 
sequentially, and the parallelization will be added in later. It passes all 
the test cases we give it, and returns the output as bash does. It waits for 
all the child processes spawned in it to close before returning.

Note that there is one race condition in our shell. If you have pipe with one 
side being a subshell that uses a file that the other side uses directly for 
its output, there will be a race condition, that will sometimes work and 
sometimes not.

For Part 1C:
We added the parallelization. We scheduled it by "ranking" each task based on
the dependencies before it. The dependencies are discovered by using an indexed
version of all the files in the commands. We sort the tasks accordingly to 
their rank. The we execute the commands of the same rank at the same time, 
spawning off child processes to execute each command. We wait for all in one 
rank to finish, then go to the next rank until we are finished.

We also added parallelization to the subshells. We take all the sequence 
commands and check their parallelizability just like in the normal shell.