Batch reloading

The command interpreter reloads the content of a batch after each execution of a line or a bracketed group.

If you start the following batch and change echo A to echo B in the batch shortly after starting it, the output will be B.

@echo off
ping -n 6 127.0.0.1 >nul & REM wait
echo A

What is on a single line does matter; changing echo A in the following batch after running it has no impact:

@echo off
ping -n 6 127.0.0.1 >nul & echo A

Nor have after-start changes have any impact on commands bracketed with ( and ). Thus, changing echo A after starting the following batch has no impact:

@echo off
for /L %%i in (1,1,10) do (
  ping -n 2 127.0.0.1 >nul & REM wait
  echo A
)

Same happens for any other enclosing, including:

@echo off
(
ping -n 6 127.0.0.1 >nul & REM wait
echo A
)