RTFM is an initialism for the expression "read the fucking manual" or, in the context of the Unix computer operating system, "read the fucking man page". The RTFM comment is usually expressed when the speaker is irritated by another person's question or lack of knowledge. It refers to either that person's inability to read a technical manual, or to their perceived laziness in not doing so first, before asking the question.
Contents
In expurgated texts, substitutions such as "read the frickin' manual", "read the flaming manual", "read the fine manual", "read the friendly manual", or similar variants are used. Initialisms similar to RTFM include "STFW" ("search the fucking web"), "GIYF" ("Google is your friend") and "LMGTFY" ("let me Google that for you"). These indicate that the questioner could have easily found the answer to their question on the World Wide Web.
Many alternative expansions for "RTFM" exist, as do many similarly-themed alternative initialisms.
Possible origins
The initialism appeared in print in 1979 on the table of contents page of the LINPACK User's Guide in the form "R.T.F.M." -- Anonymous, suggesting that it was already well established. Cleve Moler has since revealed that a visit to Argonne National Laboratory by Tektronix software manager Ned Thanhouser (grandson of Edwin Thanhouser) during the development of MATLAB led to the anonymous quote.
John Bear's 1983 book Computer Wimp! 166 Things I Wish I Had Known Before I Bought My First Computer! discusses the author hearing employees of a computer store mention RYFM ("read your fucking manual").