In addition to the predefined commands, Virtual File Services (VFS) can also be used to implement much more complex interfaces by allowing write operations to be sent to user-defined functions and then returning the results of those functions to subsequent read operations. VFS allows any program that can handle file I/O to interact with functions in the file system, which allows you to implement your own interfaces using any tool that has file system access.
For example, scripting languages (like PERL) can be used to manage system functionality using standard file system functions. The current NSS ConsoleOne interface is implemented as commands written to the manage.cmd and nds.cmd command files in the admin volume.
This section covers the following concepts: