Scott Burton, 28, was heard to remark that he was going "to stab someone" resulting in the police being called.
He pleaded guilty to one offence of possession of a knife at a previous hearing.
Mr Alexander Barnfield, prosecuting, said: "On October 29 police officers were called to an address to reports of a male in possession of a knife who was making various threats that he was going to stab someone and he was going to kill them. He left the address and went to School Court, in Wellington.
"The officers went to that address and knocked on the door. They then saw Burton walking in the street. He was seen holding a knife in his hand.
"An officer felt that he needed to draw his taser. He shouted to him to put down the knife which he did. The 12-inch kitchen knife was thrown to the floor."
Mr Barnfield also said the defendant had previous convictions dating to 2009 including possession of a knife and possession of an offensive weapon in a public place.
In mitigation Miss Debra White told Shrewsbury Crown Court that Burton had mental health illnesses and had issues with his medication levels prior to the coronavirus pandemic. She said he had been in custody since his arrest more than five weeks ago.
Burton, of Hurleybrook Way in Leegomery, was given credit for his guilty plea and for staying out of trouble since 2016. The court also took into account the fact that he did not receive his normal level of mental health support earlier in the year.
Sentencing him Judge Peter Barrie said Burton went out "looking for a confrontation" and had armed himself.
"Things can get out of hand and the potential consequences can be so severe that the court will never accept the argument that you will take a knife just in case of what might happen.
"That is not a defence," the judge said.
At the hearing at Shrewsbury on Tuesday he jailed Burton for 140 days. He must serve half before being released on licence to be followed by a 12-month supervision order. He also ordered the forfeiture and destruction of the knife.