User turns:
user: I have a list of student record in this directory, could you find me where is it by telling me its name and using 'find'?
user: Look at the student_record.txt and tell me the average score.
user: What about the standard deviation?

Involved APIs: GorillaFileSystem
MathAPI
Ground-truth function call path:
GorillaFileSystem.touch
GorillaFileSystem.echo
GorillaFileSystem.sort
GorillaFileSystem.wc
MathAPI.mean