Toy shell implementation for exercise.

$ git clone https://github.com/ViciousPotato/small-fish.git
$ cd small-fish
$ make
$ ./fish

Currently support command execution, output/input redirect, and piping.

examples:

ls
ls | wc -l | wc -l
ls >> a
echo < a
ls > a

Also some useless builtins :P

Add more tests.