Groups are a way for you and your partner to have access to each
other's account.  This way you can both work in your own accounts yet
still share code.  The old way of doing this was to only work in one
account and both partners would have to know the password.

If you want to be part of a group, email us at cs131f@ieng9.ucsd.edu 
and we'll have acs set it up.  Once that is done, you need to set the
group and permissions of the directories and files you wish to share:

  chgrp <group> <directory>
  chmod g+srx <directory>
  cd <directory>
  chmod g+rw <file>

Then you should be all set.  The 's' flag in chmod ensures that all new
files created get the same group as the directory.