1. Log on to UNIX if needed.

2. Examine your extended listing to see your default access 

permissions.  If you can, check the access permissions of the root (/) 

directory.

3.List your machine directory, and then remove your own read 

and execute access permissions and try to list it again.  Restore the 

read access and try it.  Then restore the execute access.

4. Remove the write permission for the file my.address in your 

home directory, then try to add the date line to the file.  Restore 

the write permission and try listing it again.

5. If your files have read permissions for the group, remove it for a 

few files.  Get another group member to try to read those files.  

Restore the permissions if you want.

6. Remove your group's permission to search the machine 

directory. Now you can put private files there!

7. If you know the userid of another user in your group, try to 

display (with cat) a file you don't have read access to.  Try to add a 

date line to a file you don't have write access to.


If it doesn't work:

A. Check your access regularly as you perform these exercises.  
you use chmod, follow it with ls -l .

B.  If you don't have access to anyone else's files or directories, try 
changing your own access to your files.  Be sure to restore it before 
going on.

Questions? Robert Katz:rkatz@ned.highline.edu
Last Update July 16, 2002