Example for searching Citrix Receiver install GUIDs and outputting to a text file.
del guids.txt
:: If txt file exists. We want a fresh one to hold the guids.
FOR /F “skip=2 tokens=2,*” %%A IN (‘reg.exe query “HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\Citrix\PluginPackages\XenAppSuite” /s /v “ProductCode”‘) DO echo %%B>>guids.txt