Microsoft Exchange Server 2013 : Using Windows PowerShell (part 2) - Running and using cmdlets, Running and using other commands and utilities

Windows PowerShell introduces the concept of a cmdlet (pronounced commandlet). A cmdlet is the smallest unit of functionality in Windows PowerShell. You can think of a cmdlet as a built-in command. Rather than being highly complex, most cmdlets are quite simple and have a small set of associated properties.

You use cmdlets the same way you use any other commands and utilities. Cmdlet names are not case sensitive. This means you can use a combination of both uppercase and lowercase characters. After starting Windows PowerShell, you can type the name of the cmdlet at the prompt, and it will run in much the same way as a command-line command.

For ease of reference, cmdlets are named using verb-noun pairs. As Table 1 shows, the verb tells you what the cmdlet does in general. The noun tells you what specifically the cmdlet works with. For example, the Get-Variable cmdlet gets a named Windows PowerShell environment variable and returns its value. If you don’t specify which variable to get as a parameter, Get-Variable returns a list of all Windows PowerShell environment variables and their values.

You can work with cmdlets in several ways:

You can enter any command or cmdlet you can run at the Windows PowerShell command prompt into a script by copying the related command text to a file and saving the file with the .ps1 extension. You can then run the script in the same way you would any other command or cmdlet.

From the Windows command-line environment or a batch script, you can execute Windows PowerShell cmdlets with the -Command parameter. Typically, when you do this, you also want to suppress the Windows PowerShell logo and stop execution of profiles. After doing this, you can type the following command at a command prompt or insert it into a .BAT script:

powershell -nologo -noprofile -command get-service

Finally, when you are working with Windows PowerShell, the current directory is not part of the environment path in most instances. Because of this, you typically need to use “./” when you run a script in the current directory, such as:

./runtasks

Because Windows PowerShell runs within the context of the Windows command prompt, you can run all Windows command-line commands, utilities, and graphical applications from within Windows PowerShell. However, remember that the Windows PowerShell interpreter parses all commands before passing off the command to the command prompt environment. If Windows PowerShell has a like-named command or a like-named alias for a command, this command, and not the expected Windows command, is executed.

Non–Windows PowerShell commands and programs must reside in a directory that is part of the PATH environment variable. If the item is found in the path, it is run. The PATH variable also controls where the Windows PowerShell looks for applications, utilities, and scripts. In Windows PowerShell, you can work with Windows environment variables using $env. To view the current settings for the PATH environment variable, type $env:path. To add a directory to this variable, use the following syntax:

$env:path += ";DirectoryPathToAdd"

where DirectoryPathToAdd is the directory path you want to add to the path, such as:

$env:path += ";C:\Scripts"

To have this directory added to the path every time you start Windows PowerShell, you can add the command line as an entry in your profile. Profiles store frequently used elements, including aliases and functions. Generally speaking, profiles are always loaded when you work with Windows PowerShell. Keep in mind that cmdlets are like built-in commands rather than standalone executables. Because of this, they are not affected by the PATH environment variable.