How to extract deployed WSP solution from SharePoint FARM using PowerShell

It is always recommended to backup your existing code, packages and all other important stuff before a new deployment. The same is applicable to SharePoint as well.

Well, you can use PowerShell to extract/download the wsp solution from SharePoint FARM.

Extract wsp solution using PowerShell script
$farm = Get-SPFarm
$file = $farm.Solutions.Item("mysolution.wsp").SolutionFile
$file.SaveAs("c:\mysolution_backup.wsp")

where,
mysolution.wsp = the name of solution which you want to extract
mysolution_backup.wsp = the name by which you want to save the solution