What is "shakes hands"

Usage examples of "shakes hands".

He shakes hands with one of the boys and points at me, and a couple of minutes later I am making tea while an eighteen-year-old who wants me to call him Monkey rolls a cigarette at my kitchen table.

Duke Courtney is the man in any group who shakes hands most vigorously and happily.

He kisses her dutifully, shakes hands with me, and then disappears to make us breakfast.