[Lua][Error]

I'm making a movie theater and was wanting a program to turn on the house lights before/after the movie.

this is the code i am trying to use.

redstone.setOutput(front, true)

[error] Bad argument : String expected: Got nil.
[question] What am i doing wrong?

You need to put front in quotes.

In Lua, strings are surrounded by quotes "string", apostrophes 'string', or doublebrackets [[string]].
Variable names are never escaped, even if they contain strings.