Enduring rocker Willie Nile is the walking example of pure rock 'n' roll. Black clad and cocksure, the man defines cool. But this New York City musician ain't cliché; he's classic. Since the early 1980's, Nile has been churning out greasy denim and leather, three on the tree anthems that resonate all the way back to the cheap seats in stadiums as well as assorted gin joints and dives. Nile is taking a back seat of sorts this time around to pay tribute to his hero, Bob Dylan, on his latest album, "Positively Bob."