Beloved singer-songwriter John Prine would have turned 80 this fall, and his family and the nonprofit set up in his name have announced a tribute concert to take place on October 8 at the Chicago Theatre. Titled Souvenirs: 80 Years of John Prine, the gig will feature a litany of special guests including Alynda Segarra of Hurray for the Riff Raff, Amos Lee, Andrew Sa, Briscoe, Jon Langford, Josh Ritter, Joy Oladokun, Kathleen Edwards, Margo Price, Noeline Hofmann, Ratboys, Shemekia Copeland, Stev