Police have released an e-fit of an attacker who punched a man to the jaw and attacked him with a knife.
The victim, 27, was walking along the old canal path behind Albion Street, Swindon, on 30 June when he was approached and assaulted.
When he tried to defend himself, the attacker pulled out a knife and lunged at him.
The victim shielded himself with his work bag, which was slashed several times.
A police spokesman said the victim's shirt was also cut in the unprovoked attack, but he did not suffer any serious injury.
The offender is described as white, 6ft tall, skinny and with short, light brown hair.
He was wearing dark blue jeans and a light blue hoody with a black circle on the front with three letters.
Anyone who recognises him is asked to contact police.