Dubliner Stephen Stokes appeared before Letterkenny Circuit Court in Co Donegal after pleading guilty to robbing Kernan's Spar at Lower Main Street in Letterkenny on the evening of July 8th, 2019.
Stokes' girlfriend stood watch outside as he burst into the shop around 10.30pm and told shop assistant Mark Hegarty to fill the bag.
He brandished a kitchen knife at Mr Hegarty while a customer also stood terrified in the shop.
Stokes, aged 28, threw the shop assistant a shopping bag and shouted "Give me the money and don't f*** about. I know where you live."
He continued to shout and ordered the employee to put some cigarettes in the bag also.
Stokes then pointed the knife at both the assistant and the customer and told them not to call the Gardai for half an hour.
Gardai launched an investigation into the raid and recognised Stokes who was not wearing a mask from CCTV.
The following day he was arrested in a nearby hostel and was very abusive to Gardai, the court was told.
Some of the cigarettes were recovered but none of the cash was ever found.
Barrister for Stokes, Mr Sean McGee, said he had suffered from various addictions growing up in the north Dublin suburb of Finglas.
He did not have an idyllic upbringing but his parents, who were both in court, continued to support him and he considers them role models, Mr McGee added.
The court heard that while in prison Stokes has now started to study psychology and is trying to turn his life around.
Stokes, who pleaded guilty to a single count of robbery, took to the witness box and said he wanted to apologise for what he had done.
"I want to apologise from the bottom of my heart, I was in a bad place at the time. I even dream about it some nights.
"I want to apologise to the Gardai for my aggression and what I did. I will try to make up for it every day of my life," he said.
Judge John Aylmer said he needed time to consider sentencing and put the case back to next Wednesday.