If you have problems like xhost: command not found, check your path with: echo $path
To change your path, edit your .cshrc file. Then either logout and log back in, or source ~/.cshrc
You can get the most current dotfiles, which will have the most recent path, and any important variables with: /usr/local/bin/getdotfiles. Your old dotfiles will be saved.
If you would like to change default shell, go to TEACH.