I needed to quickly gather the version of Microsoft Office in a mixed version environment.  Simple enough, let's grab the version of Word:

reg query "HKEY_CLASSES_ROOT\Word.Application\CurVer"

The response output:

HKEY_CLASSES_ROOT\Word.Application\CurVer
    (Default)    REG_SZ    Word.Application.15

Word 15 = Office 2013

Not that you couldn't have a mixed application environment but odds are good that the whole suite is Office 2013.

Great, but what can I do with this information if it just outputs to a command prompt?  I can redirect it to a file server share, perhaps?  But if I'm doing this for multiple workstations, I need to make the file name unique but identifiable:

reg query "HKEY_CLASSES_ROOT\Word.Application\CurVer" > \\SERVERNAME\SHARENAME\%computername%.txt

The filename will name reflect the computer name.

You could toss this into a login script and get your collection of uniquely labelled files but you wouldn't want to open each file.  You can gather each group of computers by version with the following:

findstr .14 *.txt
findstr .15 *.txt

.14 for Office 2010 and .15 for Office 2013 -- adjust accordingly.

You could even redirect that output to a file by adding:

> office2010.txt
> office2013.txt

... to the end of the findstr command.