Executive Summary:
| You can redefine, change through aliasing, or delete Windows PowerShell's internal functions to create the best work environment for your needs. Add your customizations to a profile script to make them persistent. |
Several PowerShell commands are actually functions predefined by an internal script that runs when PowerShell starts up. However, you can freely redefine these functions to suit your personal preferences. I'll demonstrate the techniques—redefining, aliasing, and simple deletion—primarily using PowerShell's prompt and more functions; in the process, you'll see some of the situations where redefining functions makes sense. Because the functions we're modifying are automatically created by PowerShell at startup, the changes are only temporary. They'll be reset to the default each time you start PowerShell. So, as a final topic, I'll discuss making the changes happen automatically at PowerShell startup using a PowerShell profile script.
Redefining PowerShell's Prompt Function
PowerShell's prompt is a function invoked each time a command finishes executing. The returned value from the function is used for the next onscreen prompt. The default prompt displays the current PowerShell location. In PowerShell, location is analogous to the working directory for a Windows process, but it isn't precisely the same; your current location might be a registry hive or certificate store. In any case, including the location often makes the prompt extremely long, cluttering the screen with information that I usually don't find valuable.
We can inspect the contents of the prompt function by getting its syntax information (technically, the function's definition) by entering the following command:
(Get-Command prompt).Definition
Figure 1 shows the results you'll see when using PowerShell 1.0. This is the entire internal content of the function named prompt. The location information is inserted by the $(Get-Location) element. There's also a test of the $nestedpromptlevel variable, which I won't discuss; the $nestedpromptlevel test is used to give you a special prompt (>>) when you enter a single statement on multiple lines. To create a new prompt function that removes the location data, you can simply enter the following at a command prompt (or execute it automatically in your PowerShell profile):
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