Pull someone into line

I just emailed someone and finished off by saying that I've got lots of work to do, so I'd better pull myself into line and get on with it. (which obviously I haven't just yet).

Does anyone know where and when the term 'pull someone into line' came about? Could it have a military basis?

It's often 'keep in line'. I imagine that it comes from the discipline required in drill practice where troops must be aware of rank and file.