This whole "convict" act was another phoney thing about him. He never did any real time and just spent single nights in jail because he acted like an idiot when he was drunk and high
Sorry to slay one of your musical heros, but he was a joke
This is from Wikipedia:
"Although Cash carefully cultivated a romantic outlaw image, he never served a prison sentence. Despite landing in jail seven times for misdemeanors, each stay lasted only a single night. His most infamous run-in with the law occurred while on tour in 1965, when he was arrested by a narcotics squad in El Paso, Texas. The officers suspected that he was smuggling heroin from Mexico, but it was prescription narcotics and amphetamines that the singer had hidden inside his guitar case. Because they were prescription drugs rather than illegal narcotics, he received a suspended sentence."
Well, the inmates who went to the Cash concert were...