味味A

當然不是的 因為 > 被用來當作寫檔的功能，正確的指令 倒是不知道

如: DIR/W >C:\AA.LOG

依參考下面文章 來源:http://www.computerhope.com/if.htm

The below example would work if you want it all on one line:

IF EXIST filename. (del filename.) ELSE echo filename. missing

If Command Extensions are enabled IF changes as follows:

IF [/I] string1 compare-op string2 command
IF CMDEXTVERSION number command
IF DEFINED variable command

where compare-op may be one of:

EQU - equal
NEQ - not equal
LSS - less than
LEQ - less than or equal
GTR - greater than
GEQ - greater than or equal

例1:ERRORLEVEL NUMBER比較

IF %ERRORLEVEL% LEQ 1 goto okay

例2:數字比較

@For /f "tokens=1-3 delims=/ " %%a in ('date /t') do (set sysdate=%%a-%%b-%%c) 

if %sysdate% LSS 2008-10-06 goto exit

例3:字串比較
       注意!! 寫慣java delphi等程式的人，習慣把字串前後包雙引號
                  但測試後發現，要就兩邊都要包雙引號，一邊有包一邊
                  沒包，或是變數值由其他功能得出，是會讓你產生bug
                  的….要小心.
                  如下例，set str1=ABC，ABC沒包雙引號，但if那行
                  EUQ ABC若改寫成
                  EQU "ABC"，還是run出結果會是Both is different..。

@echo off

set str1=ABC

IF %str1% EQU ABC (

  echo Both is same..

) else (

  echo Both is different..

)