批处理文件中SET命令的动态子字符串

Question

我想要一个用于测试SET命令子字符串的批处理文件，如%var:~5,3%

见下文:

@echo off
Setlocal EnableDelayedExpansion
set var=abcdefghijklmnopqrstuvwxyz
echo.
echo String: abcdefghijklmnopqrstuvwxyz
echo.
echo Samples of Substrings:
echo ~5,3   : %var:~5,3%
echo.~5 : %var:~5%
echo.~0,-2  : %var:~0,-2%
echo.
echo.Test more: (Type 000 for Exit command prompt)
:Loop
Set /P "SubStr=~"
echo.!var:~%SubStr%!
echo.
If %SubStr%==000 Exit
GoTo:Loop

输入用户的输出:~5

fghijklmnopqrstuvwxyz

和输入用户的输出:~5,2

var:~5,2

解是什么?

非常感谢。

Answer 1

:Loop
Set /P "SubStr=~"
If "%SubStr%"=="000" Exit
echo(!var:~%SubStr%!
echo(
GoTo Loop