A San Francisco taxi driver was knocked out with a metal sign during a spat with a customer over cab fare Friday morning, police said.

Police took a 46-year-old man into custody following the hack attack at Turk and Larkin streets around 3 a.m.

After arguing over the fare outside the cab, a brawl broke out. The customer got a hold of a metal sign on the street and struck the cabbie in the head with it, knocking him unconscious, cops said.

The cabbie was transported to San Francisco General Hospital, police said.

Further information was not immediately available.

maldax@sfexaminer.com

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