I have used VFP as a front end for Postgres. Just as VFP can pass DML commands like "Select * from table" it can pass DDL commands to the database like "Create table". Now if you are asking if it possible to run a linux command like 'ls' or something else then the answer is no. However, you can get the database to run the command (at least it is possible to run commands from postgres) by using store procedures.

How why not just use a terminal to access the linux box or VNC or NX?
John