Louis Davidson has a quick tip on using :EXIT in SQLCMD mode:
The first use I will cover will help you stopping from running an entire file’s worth of SQL statements without meaning to. I use this mostly when doing demo code, but it certainly finds its way into some of my other code as well. The hotkeys in SSMS for hiding the results (Ctrl-R), and executing a query (Ctrl-E) are next to each other. In a demo, where you are showing code, statement by statement, accidentally executing the entire file of queries can cause you to spend unwanted time recovering with many eyes staring back at you. This is only slightly better than accidentally running code in your office system, and losing your job.
Read on for more.