Gig

To have a job lined up. While this term is commonly used for band related work, a gig formally is the line in an american solder'w uniform that lines everything right down the middle; from their collar, to there shirt buttons and the buckle of pants. (Commonly referred to as the gig line.) So, to have a gig is slang to have something lined up straight. Having something lined up in a slang for having a job lined up and in order. While having music gig is a common use you may also have a gig if you have any short term job lined up.