In the GRASS terminal session, try a GRASS module by typing "``v.clean --help``" which will give you a list of module options. The GRASS command line is where the true power of the GIS comes into its own. GRASS is designed to allow all commands to be tied together in scripts for large bulk processing jobs. Popular scripting languages are Bourne Shell and Python, and many neat tricks to help make scripting easier are included for both. With these tools you can make a new GRASS module with only about 5 minutes of coding, complete with powerful parser, GUI, and help page template.