What is Foobar (Foo Bar)?

The term foobar or foo and bar separately are often used in sample computer programs to demonstrate to a student how to do something. Although these variables are often used in online and print tutorials they have no actual value. They simply represent generic variables the user might need. For example:

<?php
If ($foo > $bar)
{
echo $foo
}
?>

Although nobody seems to know for sure the history of foo bar, some speculate it is a twist on the military slang "fubar", while others think it came from the foo signal in electronics that would have a bar paced above it if it was inverted. Regardless of it's origin, it has become a staple piece of programming culture.