A shoplifter who pulled a knife on a security officer when he was confronted while leaving the store will serve 90 days in jail.The shoplifter, Joshua D. Dishman, 25, entered guilty pleas before General Sessions Judge Bill Locke last week. He was ordered to serve 90 days of an 11-month, 29-day sentence on the reduced charge of simple assault and was warned to stay away from Walmart. Dishman was given two consecutive 11-29 sentences, meaning he will owe the state two years in jail should he get into any more trouble in the next two years.