Problem
1. How does a local shell variable get converted to an environment variable?
2. How is the home directory set-by $HOME or /etc/passwd?
3. If TERM has the value vt220, where will you expect to find its control file?
4. How will you add the parent directory to your existing PATH? How can you make the setting permanent?
5. If you want your mailbox to be checked every minute, what setting will you make?