user account restriction

[Make Compile]

Hi guys, 

anyone can give some ideas on so i have the idea on where to start the problem. 

The problem :

a. create a linux user account which has no rights on browsing the filesystem but it has permission on /opt folder.  
b. limit the user on command built in shell. meaning user can only ls, cp, cd, only. ( if this is possible)
c. user can perform reboot or restart of linux box

I'm looking for a combination of sudoer and /bin/rbash but the problem on rbash the shell restricted cd command.


Any ideas/help would be much appreciated. Thanks