Windows Server 2012 Automation with PowerShell Cookbook

Creating and using functions

Functions could be considered one of the cornerstones of PowerShell scripting. Functions allow for individual commands or groups of commands and variables to be packaged into a single unit. These units are reusable and can then be accessed similar to native commands and Cmdlets, and are used to perform larger and more specific tasks.

Unlike Cmdlets, which are precompiled, functions are interpreted at runtime. This increases the runtime by a small amount (due to the code being interpreted by the runtime when executed), but its performance impact is often outweighed by the flexibility that the scripted language provides. Because of this, functions can be created without any special tools, then debugged, and modified ...