A thug burst into a vulnerable Corby man's home and hit him with a glass after a struggle.
Connor Gillespie, 29, left his victim bleeding after attacking him before fleeing from the scene on August 1 last year.
He was jailed at Northampton Crown Court on Monday after admitting assault occasioning actual bodily harm - but is likely to be released soon because of time spent on remand.
The court heard the thug, who has 40 offences on his record including assault and battery, burst into the victim's Montrose Street home which was also home to someone known to Gillespie.
After seeing the victim Gillespie shouted: "You got any money?"
A struggle followed and the victim tried to strike Gillespie, only for Gillespie to use a glass as a weapon and hit him on the head.
It left the victim, described in court as "vulnerable", bleeding and with a "banging headache".
Prosecuting, Luc Chignell said: "Thankfully, there do not appear to be any further injuries."
Gillespie, of Dovedale Road, ran away but was later arrested and found with an injury to his own eye.
After giving no comment in interview he later admitted assault.
A further charge of robbery, which Gillespie had denied, was ordered to lie on file.
Mitigating, Liam Muir said Gillespie was attacked first but admitted it wasn't necessary for him to use a glass.
He said: "He wants to deal with his life and he wants to move forward in a progressive fashion."
Her Honour Judge Rebecca Crane sentenced Gillespie to six months in prison, with half in custody and the remainder on licence.
Given the time he has spent on remand at HMP Peterborough, he will likely be released soon.