批量编程中%~2和%2的区别?

问题描述 投票:1回答:3

我正在学习批处理编程,我不能从字面上区分%~2和%2.也请举个例子。

batch-file
3个回答
3
投票

%2 替换第二个参数。%~2 替换第二个参数,但去掉所有引号。

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,输入 help for 来查找扩展变量时的选项(即使不在 for 命令)。)

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.

1
投票

%2是传递给批处理文件的第二个参数。

myfile.bat firstArg secondArg

因为参数通常是文件路径,所以有一些额外的语法来提取路径的一部分。

%~2 删除第二个参数上的任何""。

%~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

可能的重复。%~d0在Windows批处理文件中是什么意思?


1
投票

嗯,很简单。%2 是传递给你的bat文件的第二个参数。添加 ~ 将从您的变量中删除引号。

考虑下面这个简短的bat文件(test.bat)。

@ECHO OFF
ECHO %2
ECHO %~2

如果你在调用bat文件时使用 test.bat p1 p2 它将输出。

p2

p2

现在试试 test.bat p1 "p2"这次的输出将是:

"p2"

p2

因此,如果你没有任何引号,输出将是相同的,如果你有一些 %2 将保留他们和 %~2 会将其删除。

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