Export Farm Solution Package with PowerShell

Follow the steps below to export a farm solution package…

1. Open a text editor – such as Notepad.
2. Paste the following code snippet:

$farm = Get-SPFarm
$file = $farm.Solutions.Item("MySolutionPackage.wsp").SolutionFile
$file.SaveAs("c:\MySolutionPackage.wsp")

3. Replace the highlighted text above with the name of your solution package.
4. Save the file - give the file a name and save it with the extension ps1 (eg. extract.ps1) and place the file on the C:\ drive.
5. Open the SharePoint 2010 Management Shell
6. Navigate to the location of the script and execute it.
7. The solution package will be available on the C:\ drive

Update: If you want to download all the solutions at once you can use the following script:

$dirName = "C:\Solutions"
foreach ($solution in Get-SPSolution)
{
$filename = $Solution.SolutionFile.Name
$solution.SolutionFile.SaveAs("$dirName\$filename")
}