User turns:
user: I am alex. Check if the current directory is under my name and list all the visible and hidden contents in the current directory now, please.
user: Go to workspace directory and move one of the 'log.txt' files into a new directory 'archive'.
user: Investigate within 'log.txt' for the occurrence of the keyword 'Error'.
user: Finally, show the last several lines the file.
user: To be exact, it should be last 20 lines.

Involved APIs: GorillaFileSystem
Ground-truth function call path:
GorillaFileSystem.ls
GorillaFileSystem.find
GorillaFileSystem.mv
GorillaFileSystem.grep
GorillaFileSystem.tail