Open PowerShell and Run as Administrator

C:\Windows\System32\WindowsPowerShell\v1.0\PowerShell.exe

Adding
————
write-host “Adding Snapin”
Add-PsSnapin Microsoft.SharePoint.PowerShell
write-host “Added”

Add-SPSolution “D:\MySPSolution.wsp“
Install-SPSolution –Identity MySPSolution.wsp –WebApplication http://SP2010:8888 –GACDeployment

Update wsp
————-

Update-SPSolution –Identity MySPSolution.wsp –LiteralPath “D:\MySPSolution.wsp” –GacDeployment

unInstall wsp
————-

Uninstall-SPSolution –Identity MySPSolution.wsp –WebApplication http://sp2010
Remove-SPSolution–Identity MySPSolution.wsp

Or below

Uninstall-SPSolution -identity MySPSolution.wsp -Confirm:$false
Remove-SPSolution -identity MySPSolution.wsp -Confirm:$false

===========================================================================================================

Specific to One site
=========================================================================================================
————–
write-host “Adding Snapin”
Add-PsSnapin Microsoft.SharePoint.PowerShell
write-host “Added”

Adding
—–
Add-SPSolution “C:\CustomWebPartTest.wsp”
Install-SPSolution –Identity CustomWebPartTest.wsp –WebApplication http://SP2010:8888 –GACDeployment

Update wsp
————-

Update-SPSolution –Identity MySPSolution.wsp –LiteralPath “D:\MySPSolution.wsp” –GacDeployment

Uninstall
————–

Uninstall-SPSolution –Identity CustomWebPartTest.wsp –WebApplication http://SP2010:8888 -Confirm:$false
Remove-SPSolution -identity CustomWebPartTest.wsp -Confirm:$false

write-host “Removing Snapin”
Remove-PsSnapin Microsoft.SharePoint.PowerShell
write-host “Removed

http://msdn.microsoft.com/en-us/magazine/ee309510.aspx