Export All WSP's from Central Administration using Powershell

Export All WSP's from Central Administration using Powershell
$dirName = "c:\ExportedWSPs\"
if (!(Test-Path -path $dirName))
{
New-Item $dirName -type directory
}
Write-Host Exporting solutions to $dirName
foreach ($solution in Get-SPSolution)
{
$id = $Solution.SolutionID
$title = $Solution.Name
$filename = $Solution.SolutionFile.Name
Write-Host "Exporting '$title' to ...\$filename" -nonewline
try {
$solution.SolutionFile.SaveAs("$dirName\$filename")
Write-Host " - done" -foreground green
}
catch
{
Write-Host " - error : $_" -foreground red
}
}