"Foo", "BAR", "foobar"

Many RFC documents or code examples contain "foo", "bar", and "foobar". Today, I searched the internet for the source and meaning of these words, I understand something.

 

 

Http://zh.wikipedia.org/zh/Foobar

 

Terminology in documents related to computer programming and computer technologyFoobarIt is a common anonymous alias and is often used as a "pseudo variable.

 

Technically, "foobar" is likely to be spread from the 1960 s to the early 1970 s through the digido system manual. Another argument is that "foobar" may come from the foo signal () reversed in electronics (); this is because if a digital signal is low-level valid (that is, negative pressure or zero voltage represents "1"), there is usually a horizontal line above the signal mark, the English horizontal line is bar ". In the new hacker dictionary, "foo" may appear earlier than "FUBAR.^[1]

 

Http://www.catb.org/jargon/html/F/foobar.html

 

Foobar: N.

[Very common] Another widely usedMetasyntactic variable; SeeFooFor etymology. Probably originally propagated through decsystem manuals by Digital Equipment Corporation (Dec) In 1960 s and early 1970 s; confirmed sightings there go back to 1972. Hackers doNotGenerally use this to meanFubarIn either the slang or jargon sense. See alsoFred foobar. In rfc1639, "foobar" was made an abbreviation for "FTP operation over big address records", but this was an obviousBackronym. It has been plausibly suggested that "foobar" spread among early computer engineers partly because of FUBAR and partly because "Foo Bar" parses in electronics techspeak as an inverted Foo signal; if a digital signal is active low (so a negative or zero-voltage condition represents a "1") then a horizontal bar is commonly placed over the signal label.