Professional Windows® PowerShell

6.1. Using Parameters

You can use Windows PowerShell commands or functions without specifying any parameters. To retrieve information about all running processes, for example, you can use the get-process cmdlet and simply type:

get-process

Typically, you will see more than a screen of processes listed. The busier the machine, the more difficult it is to see what processes are running. You can use parameters to better focus the results returned by the get-process cmdlet. For example, with the get-process cmdlet, you can use a processName parameter, an ID parameter or an inputObject parameter to specify how the cmdlet is to execute.

Windows PowerShell parameters are often used by providing a cmdlet name, then a parameter name followed by a space character, then the parameter value. For example, to retrieve information about all running svchost processes, type:

get-process -processName svchost

The cmdlet's name is get-process. The parameter's name is processName and must be immediately preceded by a minus sign (or hyphen, if you prefer). The parameter value is svchost.

If there are no whitespace characters in the value supplied for a parameter, you don't need to supply paired quotation marks or paired apostrophes around the parameter value. So, the command

get-process -processName "svchost"

is equivalent to the previous command. However, if the parameter value you want to supply contains, for example, a space character, you must enclose the value in paired quotation marks or paired ...