Great Powershell One-liners

Or, 'highly useful things you can do in Powershell':

Watching the last 20 lines of the last (log?) file in a directory:

(gci)[-1] | gc | select-object -last 20

Finding where .Net is installed:

(get-itemproperty HKLM:\software\microsoft\.netframework).InstallRoot

Pinging a URL [1]:

$temp = (new-object net.webclient).DownloadString($url)
if ($?) { write-host Passed -foregroundcolor "green" }

Getting the DNS suffix for a machine:

(Get-WmiObject -class "Win32_ComputerSystem").Domain

[1] Ok, that one's not a one-liner.