Using Invoke-Expression

In this recipe, we will use the Invoke-Expression cmdlet.

Getting ready

For this recipe, we will use the 7-zip application to compress some files. Download 7-zip from http://www.7-zip.org/.

How to do it...

Let's check out the Invoke-Expression cmdlet.

1. Open PowerShell ISE. Go to Start | Accessories | Windows PowerShell | Windows PowerShell ISE.

2. Add the following script and run it:

   $VerbosePreference = "Continue"
   
   $program = "`"C:\Program Files\7-Zip\7z.exe`""
   $7zargs = " a -tzip "
   $zipFile = " `"C:\Temp\new archive.zip`" "
   $directoryToZip = " `"C:\Temp\old`" "
   
   $cmd = "& $program $7zargs $zipFile $directoryToZip "
   
   #display final command
   Write-Verbose $cmd
   
   Invoke-Expression $cmd
   
   $VerbosePreference = "SilentlyContinue"

How it works...

The Invoke-Expression cmdlet allows PowerShell expressions to be run from PowerShell. These expressions can consist of other PowerShell statements and functions, or they can contain executables and arguments.

In this recipe, we are composing...