How to identify the application pool for a worker process (Windows Server 2012 and 2012 R2 using IIS 8)

Use the following command to determine which application pool maps to your w3wp.exe worker instance. This is particularly handy with SharePoint as it has 3 w3wp.exe processes running at any one time by default.
cd %windir%\system32\inetsrv
appcmd list wp
This will give you an output similar to the following:

C:\Windows\System32\inetsrv>appcmd list wp
WP "21192"  (applicationPool:SharePoint - 80)
WP "12256" (applicationPool:SecurityTokenServiceApplicationPool)
WP "19972" (applicationPool:5f2e9be121504641ae144bcae3b8cf6e)
DDK