Many IT professionals know OS X stands for Operating System 10.  But if you know anyone that thinks it is OS “ex,” you can prove to them the correct pronunciation using a simple command built into every Mac.

Just type this into Terminal (it is case-sensitive, as you will see)

say OS X

Your Mac will verbally say “OS Ten.”

if you instead type in:

say OS x

(notice the lowercase “x”)?  Your mac will say “OS ex.”  Thanks Apple programmers for your attention to detail.

Now if only such proof existed for GIFs…