@echo off & setlocal EnableDelayedExpansion 
:: 計算字符串的長度 
:: 
:: 
:began 
set mystr= 
set /p mystr=輸入要計算長度的字符串(直接回車退出): 
if not defined mystr goto :eof 
for /l %%i in (0,1,1000) do if "!mystr:~%%i,1!"=="" set strlen=%%i && goto :_endfor 
:_endfor 
::echo 字符串: "%mystr%" 
echo 長 度: %strlen% 
set strlen= 
goto began

該方案的缺陷是：當(dāng)字符串長度超過1000的時候，將不能探測到；不過變量能接收的長度好象還不能超過1000

另外一種方案：

復(fù)制代碼代碼如下:

@echo off 
:: Based on willsort's codes code by JM 2006-10-9 CMD@XP 
:: 出處：http://www.cn-dos.net/forum/viewthread.php?tid=19819 
set mystr= 
set /p mystr=輸入要計算長度的字符串(直接回車退出): 
if not defined mystr goto :eof 
set count=0 
setlocal enabledelayedexpansion 
:intercept 
set /a count+=1 
for /f %%i in ("%count%") do if not "!mystr:~%%i,1!"=="" goto intercept 
echo 長 度: %count% 
pause 
goto :eof 

@echo off 
:: 
:: 
:began 
set /p mystr=輸入要計算長度的字符串: 
echo %mystr:~0,1% | findstr /i "q" 1>nul 2>nul && exit rem 輸入q退出 

call :bflen "%mystr%" rem 這兩句調(diào)用bflen，返回長度到變量ret中。 
echo 字符串: "%mystr%" 
echo 長 度: %ret% 

goto began 

:bflen rem 真麻煩，初始化要單獨拿出來。 
set num= 
set str= 
set ret= 
set str=%1 
:len rem 計算字符串長度 
set str=%str:~0,-1% 
set /a num = %num% + 1 
if defined str goto len 
set /a ret = %num% - 2 
set num= 
goto :eof 