/ha-pə-lē/
adv. Of software, used to emphasize that a program is unaware of some important fact about its environment, either because it has been fooled into believing a lie, or because it doesn't care. The sense of 'happy' here is not that of elation, but rather that of blissful ignorance.
"The program continues to run, happily unaware that its output is going to /dev/null."