What should I wear to this concert?

I am going to a concert/festival for a bunch of bands [nevershoutnever, a rocket to the moon, stereo skyline,etc.] at a small venue. I have no clue what to wear, and I don't want to be the one that is dressed wrong. What do people wear to a concert like this? I have a nevershoutnever shirt but I am not sure if it is the best idea to wear it...help please :]