Optional functionality: Add a PATH variable

[edgariscoding]

The shell that you are building is fairly simplistic. For teams who have completed all requirements for this program and are looking for an additional challenge, teams may add the following optional functionality to gain bonus points added to your team’s overall score:

Add a PATH variable.

However, all required functionality must be implemented prior to attempting this extra credit work as no points will be given for attempting this functionality if all requirements have not been completed. In other words, make sure your program is complete before attempting this extra credit.

[edgariscoding]

Implemented in #20.

PATH variable can only be changed in interactive mode.

Use:

prompt> PATH=/new/path