RTFM (read the *blank* manual)
Again, likely invented in the '80s on Usenet, where scolding people
who ask inane questions is commonplace. Also, thick manuals were once
included with software back in those days and reading them was even
considered a good idea. The very first post I could find on Usenet
that includes RTFM was in 1983 and refers to the term having been used
by "VMS people." VMS is an old server operating system.
https://www.computerworld.com/article/2534004/opinion--fwiw----the-origins-of--net-shorthand.html?page=2
--- SoupGate-Win32 v1.05
* Origin: fsxNet Usenet Gateway (21:1/5)