“ECHO此时出人意料”在FOR / IF声明中

Question

下面是一段代码，它正在抛出一个＆＃34;此时ECHO意外发生了＃34;错误：

SET SN_List_Filename=SN_LIST_%DATE:/=%.txt
SET SN_List_Filename_Temp=%SN_List_Filename%.temp

ECHO Date: %DATE:~0,2%-%DATE:~3,2%-%DATE:~-4% > %SN_List_Filename_Temp%
ECHO SN List: >> %SN_List_Filename_Temp%
ECHO. >> %SN_List_Filename_Temp%

IF NOT EXIST %SN_List_Filename% (
    ECHO. > %SN_List_Filename%
) ELSE (

    SET SN_List=%serial%
    SET index=0
    SET snCount=1

    FOR /f "tokens=* skip=5" %%a IN (%SN_List_Filename%) DO (

        SET SN_List=!SN_List!;%%a   
        FOR /F "tokens=* delims=;" %%b IN ("%SN_List%") DO (
            IF %%a==%%b (
                ECHO %%b>> %SN_List_Filename_Temp%
            )
        )
    )
)

如果＆＃34; %% a == %% b＆＃34;则会引发错误。比较满意。

* N.B。设置enabledelayedexpansion并将ECHO设置为off。