Ever wanted to find out if an Update or Hotfix was installed on a server or workstation? Sure, you can look at the Update History or open the Add/Remove Programs Control Pannel and look at the list of Installed Updates, but you cannot search that list in the UI by using anything but your feable human eyes, and who wants to trust that? Here is a nice command line that’ll give you a really detailed list of what is installed.
wmic qfe list
In addition to what is installed, it also tells you who installed it, when it was installed and the link to the KB Article web page. But it's still just a list, so how does that help? You can redirect the output of that command to a text file and then open it up in Notepad where you can hit Ctrl+F and let the computer find the KB number for you.
wmic qfe list > updatelist.txt && updatelist.txt
By the way, "QFE" means "Quick Fix Engineering". It is another name that Microsoft sometimes uses instead of "patch" or "hotfix", but it hasn’t really caught on yet despite the fact that the term has been around since at least Windows 2000.
Another option is to use the "systeminfo" utility. This command will onlu list the KB numbers but it also lists other information about the system that might be useful. You can redirect the output to a text file and open it up to search for the KB number you are looking for.
systeminfo > sysinfo.txt && sysinfo.txt
Be aware that this list includes only hotfixes that apply to the Operating System and not other products that are installed, including Microsoft services like UAG, TMG, SQL and Exchange. To see those, click on the Start button and type in "View Installed Updates". That will allow you to open the Programs and Freatures control panel.
There is a search box in the upper right corner, but the KB number sometimes is not listed in the name of the update, so you might end up needing to eyeball it anyway.