There are two types of connectors, redefine and prefix. They can be applied to the input and output side of a pipeline, giving four combinations. The second component of the connector names the side it is on in a redefine connector. A short-through connection has no stages between the connectors. A label is a character string, at the beginning of a stage.
Case is respected in a label.
A label is declared the first time a particular label is used in a pipeline specification. The scope of a label is the pipeline specification being scanned. Write local options followed by the name of a program to run and its argument string after the label where it is declared. This defines the primary streams for the stage. The secondary and subsequent streams for a stage with a label are defined when you reference the label later in the pipeline spec- ification.