批處理編程中％〜2和％2之間的區別？

Question

我正在學習批量編程，我無法區分％〜2和％2。還請提供一個示例。

Answer 1

%2在第二個參數中替代。 %~2替代第二論據與但刪除任何引號：

C:\Temp>type t.cmd 
@echo off 
echo %%2 is: %2 
echo %%~2 is: %~2 

C:\Temp>t.cmd first second third 
%2 is: second 
%~2 is: second 

C:\Temp>t.cmd first "second third" 
%2 is: "second third" 
%~2 is: second third 

在命令提示符下，鍵入help for擴大變量（即使不是其主要工作在for命令）時找到的選項：

In addition, substitution of FOR variable references has been enhanced. 
You can now use the following optional syntax: 

    %~I   - expands %I removing any surrounding quotes (") 
    %~fI  - expands %I to a fully qualified path name 
    %~dI  - expands %I to a drive letter only 
    %~pI  - expands %I to a path only 
    %~nI  - expands %I to a file name only 
    %~xI  - expands %I to a file extension only 
    %~sI  - expanded path contains short names only 
    %~aI  - expands %I to file attributes of file 
    %~tI  - expands %I to date/time of file 
    %~zI  - expands %I to size of file 
    %~$PATH:I - searches the directories listed in the PATH 
        environment variable and expands %I to the 
        fully qualified name of the first one found. 
        If the environment variable name is not 
        defined or the file is not found by the 
        search, then this modifier expands to the 
        empty string 

The modifiers can be combined to get compound results: 

    %~dpI  - expands %I to a drive letter and path only 
    %~nxI  - expands %I to a file name and extension only 
    %~fsI  - expands %I to a full path name with short names only 
    %~dp$PATH:I - searches the directories listed in the PATH 
        environment variable for %I and expands to the 
        drive letter and path of the first one found. 
    %~ftzaI  - expands %I to a DIR like output line 

In the above examples %I and PATH can be replaced by other valid 
values. The %~ syntax is terminated by a valid FOR variable name. 
Picking upper case variable names like %I makes it more readable and 
avoids confusion with the modifiers, which are not case sensitive. 

Answer 2

％2是傳遞給批處理文件的第二個參數。

myfile.bat firstArg secondArg 

因爲參數通常是文件路徑，所以有一些額外的語法來提取部分路徑。

％〜2刪除第二個參數上的任何「」。

%~1   - expands %1 removing any surrounding quotes (") 
%~f1  - expands %1 to a fully qualified path name 
%~d1  - expands %1 to a drive letter only 
%~p1  - expands %1 to a path only 
%~n1  - expands %1 to a file name only 
%~x1  - expands %1 to a file extension only 
%~s1  - expanded path contains short names only 
%~a1  - expands %1 to file attributes 
%~t1  - expands %1 to date/time of file 
%~z1  - expands %1 to size of file 
%~$PATH:1 - searches the directories listed in the PATH 
       environment variable and expands %1 to the fully 
       qualified name of the first one found. If the 
       environment variable name is not defined or the 
       file is not found by the search, then this 
       modifier expands to the empty string  

%~dp1  - expands %1 to a drive letter and path only 
%~nx1  - expands %1 to a file name and extension only 
%~dp$PATH:1 - searches the directories listed in the PATH 
       environment variable for %1 and expands to the 
       drive letter and path of the first one found. 
%~ftza1  - expands %1 to a DIR like output line 

可能重複： What does %~d0 mean in a Windows batch file?

Answer 3

線輪，這是簡單的。 %2是傳遞給您的bat文件的第二個參數。添加~將刪除變量中的引號。

考慮以下簡稱BAT文件（test.bat的）：

@ECHO OFF 
ECHO %2 
ECHO %~2 

德恩你打電話給你的BAT文件與test.bat p1 p2它會輸出：

P2

P2

現在試試test.bat p1 "p2"！這一次輸出將是：

「P2」

P2

所以，如果你沒有任何引號的輸出將是相同的，如果你有一些%2會保持他們和%~2將刪除它們。