Unlambda
Unlambda is a minimalistic esoteric programming language that is known for its simplicity and lack of traditional programming constructs. It is primarily used for educational purposes and to explore the principles of functional programming.
Hello, world code example:
`r```````````````.G.o.o.d.b.y.e.,. .W.o.r.l.d.!i
Popularity: Less than 1% of developers are using or have used this language.*
*According to StackOverflow's 2023 survey.