Sharepoint WSP Solution BackUp and Deployment

//For WSP Backup
$farm = Get-SpFarm 
$file = $farm.Solutions.Item("WSP_Solution.wsp").SolutionFile 
$file.SaveAs("E:\FolderName\WSP_Solution.wsp")


//Before add WSP solution, Retract solution from central admin Farm solution and remove Solution from there.
Add-SPSolution "E:\FolderName\WSP_Solution.wsp"
Install-SPSolution –Identity WSP_Solution.wsp –WebApplication "Web App url" –GACDeployment