know the ins and outs (of something)
know the ins and outs (of something)
To know the particular details and nuances of a situation, task, etc. I'm not surprised he made such a stupid mistake—he doesn’t know the ins and outs of this business. Come to me if you have any questions. I've been here seven years, so I know the ins and outs.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.