ExecuteProcess: Runs the user-defined Operating System command. The Process's StdOut is redirected such that the content that is written to StdOut becomes the content of the outbound FlowFile. This Processor is a Source Processor - its output is expected to generate a new FlowFile, and the system call is expected to receive no input. In order to provide input to the process, use the ExecuteStreamCommand Processor.
ExecuteStreamCommand: Runs the user-defined Operating System command. The contents of the FlowFile are optionally streamed to the StdIn of the process. The content that is written to StdOut becomes the content of hte outbound FlowFile. This Processor cannot be used a Source Processor - it must be fed incoming FlowFiles in order to perform its work. To perform the same type of functionality with a Source Processor, see the ExecuteProcess Processor.