Changing a batch file when its running

Question

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

Answer 1

Short answer: yes, batch files can modify themselves whilst running. As others have already confirmed.

Years and years ago, back before Windows 3, the place I worked had an inhouse menu system in MS-DOS. The way it ran things was quite elegant: it actually ran from a batch file that the main program (written in C) modified in order to run scripts. This trick meant that the menu program itself was not taking up memory space whilst selections were running. And this included things like the LAN Mail program and the 3270 terminal program.

But running from a self-modifying batch file meant its scripts could also do things like load TSR programs and in fact could do pretty much anything you could put in a batch file. Which made it very powerful. Only the GOTO command didn't work, until the author eventually figured out how to make the batch file restart itself for each command.