Windows PowerShell Handles Console Input and Display

When you type a command, Windows PowerShell always processes the command-line input directly. Windows PowerShell also formats the output that you see on the screen. This is significant because it reduces the work required of each cmdlet and ensures that you can always do things the same way regardless of which cmdlet you are using. One example of how this simplifies life for both tool developers and users is command-line help.

Traditional command-line tools have their own schemes for requesting and displaying help. Some command-line tools use /? to trigger the help display; others use -?, /H, or even //. Some will display help in a GUI window, rather than in the console display. Some complex tools, such as application updaters, unpack internal files before displaying their help. If you use the wrong parameter, the tool might ignore what you typed and begin performing a task automatically.

When you enter a command in Windows PowerShell, everything you enter is automatically parsed and pre-processed by Windows PowerShell. If you use the -? parameter with a Windows PowerShell cmdlet, it always means "show me help for this command". Cmdlet developers do not have to parse the command; they only need to provide the help text.

It is important to understand that the help features of Windows PowerShell are available even when you run traditional command-line tools in Windows PowerShell. Windows PowerShell processes the parameters and passes the results to the external tools.

Note:

If you run an graphic application in Windows PowerShell, the window for the application opens. Windows PowerShell intervenes only when processing the command-line input you supply or the application output returned to the console window; it does not affect how the application works internally.