I am running a long running batch file. I now realize that I have to add some more commands at the end of the batch file (no changes to exisiting content, just some extra co
The command interpreter remembers the line position byte offset it's at in the batch file. You will be fine as long as you modify the batch file after the current executing line position byte offset at the end of the most recently parsed line of code.
If you modify it before then it will start doing strange things (repeating commands etc..).