User turns:
user: Go to documents folder in CWD. Next, from the first document in current folder. What does the last line look like?
user: Write the difference of the first two file into a new file call file5.txt.

Involved APIs: TwitterAPI
GorillaFileSystem
Ground-truth function call path:
GorillaFileSystem.ls
GorillaFileSystem.cat
GorillaFileSystem.sort
GorillaFileSystem.diff
TwitterAPI.post_tweet