It appears that the parser provided to you for Assignment #6 is very picky.
For example, an ending ampersand ('&') must be proceeded by a space (0x20)
character in order for the parser to be able to pick it up. Also, when using
pipes, you must keep whitespace on either side of the pipe character.

This is a flaw in the parser, but it is too late to be fixed now. Just
keep this in mind when testing your shell. You won't be graded down if a problem
in the parser causes your shell to dump core.