The Unix shell server can be accessed via ssh. The command is ssh user@hobbes.seas.gwu.edu. You can leave off the userid and the at sign if the system you are connecting from uses the same userid as your SEAS account.
This same method can be used in order to copy files off of the system using either scp or sftp. scp works in the same manner as cp on the Unix command line, while sftp provides a basic interface, similar to ftp.
scp filename userid@hobbes.seas.gwu.edu:/path/to/file
scp userid@hobbes.seas.gwu.edu:/path/to/file filename
sftp userid@hobbes.seas.gwu.edu