Mr MacNamnee's life was in danger after the attack
A man who carried out armed attacks on a shopkeeper and a taxi driver has been jailed for 11 years and three months.
Robert Williamson has been assessed as being of very high risk of reoffending and has shown no remorse for his actions
The High Court in Glasgow heard that Williamson, 23, has been diagnosed with post traumatic stress disorder because of childhood abuse.
Williamson stabbed a shopkeeper and a taxi driver in Glasgow last year.
Jailing Williamson judge Lord Brailsford said: "You show no empathy for your victims and the risk assessment shows you are at a very high risk of reoffending and causing harm to the public.
"Matters like this cannot be tolerated by the courts. I do accept that you were the victim of an unfortunate childhood and I'm prepared to accept that your lack of empathy is a direct result of the abuse you suffered as a child.
"All I can hope is that while you are in prison you will get the counselling you require."
Williamson stabbed shopkeeper Mohammed Khan in the back and grabbed two packets of cigarettes from a shop in Glasgow on 14 January last year.
Six months later he stabbed taxi Bernard MacNamee on the head and body because he did not have £2.30 to pay the fare.
Paul Kearney, prosecuting, said that Mr MacNamnee's life was in danger because of the closeness of the wounds to major organs.
Williamson also returned to shop and attacked Mr Khan for a second time with a baton before fleeing with £200 and a some cigarettes.
In court Williamson admitted assaulting Mr Khan and robbing him of a quantity of cigarettes.
He also admitted slashing taxi driver Mr MacNamee.
Williamson also pleaded guilty to, while acting with others, assaulting Mr Khan by hitting him over the head with a baton.
Solicitor advocate Liam O'Donnell said that his client had had a difficult childhood and he needed help to address his problems.