How do I unzip multiple files? - powershell

Question

I am attempting to loop through zip files in a folder and extract them. I am receiving a null error for the zip.items(). How could this value be null?
When I Write-Host $zip the value that is posted is System.__ComObject.
$dira = "D:\User1\Desktop\ZipTest\IN"
$dirb = "D:\User1\Desktop\ZipTest\DONE\"
$list = Get-childitem -recurse $dira -include *.zip
$shell = new-object -com shell.application
foreach($file in $list)
{
$zip = $shell.NameSpace($file)
foreach($item in $zip.items())
{
$shell.Namespace($dirb).copyhere($file)
}
Remove-Item $file
}
The error message I am receiving is:
You cannot call a method on a null-valued expression.
At D:\Users\lr24\Desktop\powershellunziptest2.ps1:12 char:29
+ foreach($item in $zip.items <<<< ())
+ CategoryInfo : InvalidOperation: (items:String) [], RuntimeException
+ FullyQualifiedErrorId : InvokeMethodOnNull

Answer 1

$file is a FileInfo object, but the NameSpace() method expects either a string with a full path or a numeric constant. Also, you need to copy $item, not $file.
Change this:
foreach($file in $list)
{
$zip = $shell.NameSpace($file)
foreach($item in $zip.items())
{
$shell.Namespace($dirb).copyhere($file)
}
Remove-Item $file
}
into this:
foreach($file in $list)
{
$zip = $shell.NameSpace($file.FullName)
foreach($item in $zip.items())
{
$shell.Namespace($dirb).copyhere($item)
}
Remove-Item $file
}

Answer 2

If you have 7-zip in your $env:path
PS> $zips = dir *.zip
PS> $zips | %{7z x $_.FullName}
#unzip with Divider printed between unzip commands
PS> $zips | %{echo "`n`n======" $_.FullName; 7z x $_.FullName}
you can get 7-zip here:
http://www.7-zip.org/
PS> $env:path += ";C:\\Program Files\\7-Zip"
Explanation:
Percent followed by curly braces is called the foreach operator: %{ }
This operator means that "Foreach" object in the pipe, the code in the curly braces is called with the object placed in the "$_" variable.

Answer 3

You're missing the shell initialization.
$shell = new-object -com shell.application
use it before the NameSpace.