The Origin of Foo and Bar

Foo & bar are terms found in programming used for generic placed holder references.

It originates from the military slang FUBAR (fucked up beyond all recognition/any repair/all reason) and dates from World War II.

The Oxford English Dictionary lists Yank, the US Army Weekly magazine (1944, 7 Jan. p. 8) as its earliest citation: "The FUBAR squadron. FUBAR? It means 'Fouled Up Beyond All Recognition'.