The shaderfx command enables you to query information about your ShaderFX graph such as the number of nodes in your graph, the list of properties in your node, as well as perform actions such as add or delete a node, create or break connections, as well as specify the DAG path of the ShaderFX shader that you are working on.
For details on the shaderfx command and a description of its flags, enter shaderfx – help in the MEL command line.