::code by lxmxn @ cn-dos.net .
::目的：幫助新手們更好的理解變量字符截取功能.
::Date 2006-12-16 .
::說明：有的變量截取之后值為空，這是正常的.
::
@echo off&setlocal EnableDelayedexpansion
::設置變量var的值：
set var=0123456789ABCDEF
call :begin
for /l %%a in (1,3,15) do (
for /l %%b in (1,4,15) do (
call :printf %%a %%b
)
)
call :begin
for /l %%a in (1,4,15) do (
for /l %%b in (-1,-3,-15) do (
call :printf %%a %%b
)
)
call :begin
for /l %%a in (-2,-3,-15) do (
for /l %%b in (1,4,15) do (
call :printf %%a %%b
)
)
call :begin
for /l %%a in (-1,-4,-15) do (
for /l %%b in (-2,-3,-15) do (
call :printf %%a %%b
)
)
pause
endlocal&cls&echo.
echo 演示結束了，任意鍵退出……
pause>nul
goto :eof

::輸出結果：
:printf
echo %%var:~%1,%2%% 截取之后的字符為: !var:~%1,%2!
goto :eof

::清理屏幕：
:begin
echo/&pause&cls&echo.
echo 變量var的值為: %var%
echo.
goto :eof