begin, process, end, and clean

A script or function often begins with comment-based help followed by a param block. Following this, one or more named blocks may be used.

The named blocks are:

• begin
• process
• end
• dynamicparam
• clean

The dynamicparam block is explored in Chapter 18, Parameters, Validation, and Dynamic Parameters, as it is more complex and ties to more advanced parameter usage than covered by this chapter.

In a script or function, if none of these blocks are declared, content is in the end block.

The named blocks refer to a point in a pipeline and, therefore, make the most sense if the command is working on pipeline input.

In a filter, if none of these blocks are declared, content is in the process block. This is the only difference between a function and a filter.

This difference in a default block is shown in the following pipeline example. The function must explicitly declare a process block to use the ...