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為什麼從 SENDTO 呼叫 BAT 時 CMD 子字串不起作用？

tag-icon • tag-icon windows-7 windows command-line batch batch-file
為什麼從 SENDTO 呼叫 BAT 時 CMD 子字串不起作用？

我編寫了一個 BAT 檔案來刪除檔案名稱中的前導“@”。 (請不要問為什麼！...為什麼 Windows，為什麼 CMD...）:)

這是 BAT 檔案：

IF EXIST "%~1" (

    FOR /F %%F IN ("%~1") DO (

        CD /D "%%~dpF"
        IF ERRORLEVEL 1 (
            ECHO.  Failed to CD to folder: %%~dpF
        ) ELSE (
            SETLOCAL ENABLEEXTENSIONS
            SET A=%%~nxF

            IF "%A:~0,1%"=="@" (

                ECHO.   RENAME "%A%" "%A:~1%"
                    RENAME "%A%" "%A:~1%"
                REM   RENAME "%%A%" "%%A:~1%"
            ) ELSE (
                ECHO.   File does not start with @:  %A%
            )
            ENDLOCAL
        )
    )
) ELSE (
    ECHO.    File not found:  %1
)

pause

當我在 DOS 視窗中從命令列運行它時，它似乎可以工作：

18:54:04.97>dir /b *foo*
@foo.txt

18:54:07.97>test@ "%cd%\@foo.txt"

18:54:18.75>IF EXIST "C:\Users\me\lbin\@foo.txt" (FOR /F %F IN ("C:\Users\me\lbin\@foo.txt") DO (
CD /D "%~dpF"
 IF ERRORLEVEL 1 (ECHO.  Failed to CD to folder: %~dpF )  ELSE (
SETLOCAL ENABLEEXTENSIONS
 SET A=%~nxF
 IF "@" == "@" (
ECHO.   RENAME "@foo.txt" "foo.txt"
 RENAME "@foo.txt" "foo.txt"
 REM   RENAME "%Afoo.txt"
)  ELSE (ECHO.   File does not start with @:  @foo.txt )
 ENDLOCAL
)
) )  ELSE (ECHO.    File not found:  "C:\Users\me\lbin\@foo.txt" )

18:54:18.77>(
CD /D "C:\Users\me\lbin\"
 IF ERRORLEVEL 1 (ECHO.  Failed to CD to folder: C:\Users\me\lbin\ )  ELSE (
SETLOCAL ENABLEEXTENSIONS
 SET [email protected]
 IF "@" == "@" (
ECHO.   RENAME "@foo.txt" "foo.txt"
 RENAME "@foo.txt" "foo.txt"
 REM   RENAME "%Afoo.txt"
)  ELSE (ECHO.   File does not start with @:  @foo.txt )
 ENDLOCAL
)
)
   RENAME "@foo.txt" "foo.txt"

18:54:18.80>pause
Press any key to continue . . .
18:54:20.74>

但是當我從 SENDTO 選單中的快捷方式運行 BAT 檔案時，該substring操作無法正確擴展 - 具體來說，「IF」沒有正確擴展 ( IF "%A:~0,1%"=="@" () - 看到了嗎？

C:\Users\me\lbin>IF EXIST "C:\Users\me\lbin\@foo.txt" (FOR /F %F IN ("C:\Users\me\lbin\@foo.txt") D
O (
CD /D "%~dpF"
 IF ERRORLEVEL 1 (ECHO.  Failed to CD to folder: %~dpF )  ELSE (
SETLOCAL ENABLEEXTENSIONS
 SET A=%~nxF
 IF "~0,1" == "@" (
ECHO.   RENAME "" "~1"
 RENAME "" "~1"
 REM   RENAME "%A~1"
)  ELSE (ECHO.   File does not start with @:   )
 ENDLOCAL
)
) )  ELSE (ECHO.    File not found:  C:\Users\me\lbin\@foo.txt )

C:\Users\me\lbin>(
CD /D "C:\Users\me\lbin\"
 IF ERRORLEVEL 1 (ECHO.  Failed to CD to folder: C:\Users\me\lbin\ )  ELSE (
SETLOCAL ENABLEEXTENSIONS
 SET [email protected]
 IF "~0,1" == "@" (
ECHO.   RENAME "" "~1"
 RENAME "" "~1"
 REM   RENAME "%A~1"
)  ELSE (ECHO.   File does not start with @:   )
 ENDLOCAL
)
)
   File does not start with @:

C:\Users\me\lbin>pause
Press any key to continue . . .

有想法嗎？

答案1

延遲擴張將導致變數在執行時而不是在解析時擴展，此選項透過命令開啟SETLOCAL。當延遲擴展生效時，可以使用!variable_name!（除了正常的%variable_name%）來引用變量

因此，分別使用!A!、!A:~0,1!和!A:~1!代替%A%、%A:~0,1%和 ，%A:~1%如下所示：

        SETLOCAL ENABLEEXTENSIONS
        SET A=%%~nxF

        IF "!A:~0,1!"=="@" (

            ECHO.   RENAME "!A!" "!A:~1!"
                    RENAME "!A!" "!A:~1!"
        ) ELSE (
            ECHO.   File does not start with @:  !A!
        )
        ENDLOCAL

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