Other common environmental variables
• $USER - the login name of the current user
• $HOME - the home directory of the current user
• $PATH - the list of directories to search for programs
• $CWD - the current working directory
• $EDITOR - name of (and optionally full path to) your favourite editor (e.g.,"vi", "/usr/bin/vim", /usr/bin/atom)
• $LANG - name of your language setting character set if you are working solely in English, thisis typically "en_US.UTF-8"