Does colonoscopy examine the entire colon? i saw something that said it only does large part..?

The "large" intestine is the colon, which is what a colonoscopy evaluates. It does not enter/evaluate the small intestine which is not part of the colon.

Colonoscopy is intended to examine the whole colon, sometimes remains a partial examination due to anatomical variation, obstruction or strictures for example, the gastroenterologist performing procedure will explain following procedure if exam incomplete.

Colonoscopy is designed to examine the whole colon/large intestine. Sigmoidoscopy examines on the terminal one third or so of the colon.