Using Invoke-Expression

In this recipe, we will use the Invoke-Expression cmdlet to compress some files using a free compression utility.

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 as an administrator.
2. Add the following script and run it:

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

How it works...

The Invoke-Expression cmdlet allows PowerShell expressions to run from PowerShell...