此答案将在 3 和 5 之间添加 4 .

This answer will add a 4 between a 3 and a 5.

@echo off
setlocal enabledelayedexpansion
ren in.txt in.tmp
set p=
for /f %%a in (in.tmp) do (
  if "%%a"=="5" if "!p!"=="3" Echo 4 >> in.txt
  Echo %%a >>in.txt
  set p=%%a
)
del in.tmp