停批文件只处理最后一个文件？ [英] Stop batch file only processing last file?

问题描述

我重命名* .txt文件并删除第一个X字符以下简单的批处理文件

I have the following simple batch file for renaming *.txt files and removing the first x characters

@Echo Off

for %%i in ("*.txt") do (
  set fname=%%i
  echo %fname%
  copy %fname% %fname:~9%
)

然而，这只是处理的最后一个文件？如果我在那里有4个文件，最后一个文件被复制4倍呢？

However, it only processes the last file? If I have 4 files in there, the last file gets copied 4 times as well?

我需要做什么呢？

推荐答案

的问题是，％变种％是由变量的值替换当回路第一次被解析，并在执行过程中不改变。

The problem is that %var% is replaced by the variable's value when the loop is first parsed, and doesn't change during execution.

下面是一个示范，应允许您解决您的code：

Here's a demonstration which should allow you to fix your code:

@ECHO off&setlocal&CLS
ECHO Demonstrating the use of %%var%% IN a block
ECHO.
SET var=Original value
ECHO Before the block, %%var%%=%var%
FOR %%i IN (1 2 3) DO (
  SET var=New value %%i
  ECHO loop %%i : %%var%%=%var%
  )
ECHO After the block, %%var%%=%var%
ECHO.
ECHO BECAUSE the block is first PARSED, then executed.
ECHO in the parsing process, %%var%% is replaced by its
ECHO value as it stood when the block was parsed - BEFORE execution
ECHO.
ECHO now try using a SETLOCAL ENABLEDELAYEDEXPANSION command first:
ECHO.
SETLOCAL ENABLEDELAYEDEXPANSION
SET var=Original value
ECHO Before the block, %%var%%=%var% and ^^!var^^!=!var!
FOR %%i IN (1 2 3) DO (
  SET var=New value %%i
  ECHO loop %%i : %%var%%=%var% BUT ^^!var^^!=!var!
  )
ECHO After the block, %%var%%=%var% and ^^!var^^!=!var!
ECHO.

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编

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addendum

呵呵，这么多的插入记号！大字不识一个兔子的天堂。

Oh, so many carets! An illiterate rabbit's paradise.

脱字符（ ^ ）越狱字的特殊含义，如下 - 除了％这是由另一逃脱％
所以 - 在该行

The caret character (^) "escapes" the special meaning of the character which follows - except for % which is escaped by another % So - in the line

ECHO Before the block, %%var%%=%var%

什么是呼应的是块之前，接单％，文字 VAR ，另一个单％， = 和 var值

What is echoed is "Before the block, " then a single % , the text var, another single %, = and the value of var

在 SETLOCAL ENABLEDELAYEDEXPANSION 字符！成为一个特殊字符。所以

After SETLOCAL ENABLEDELAYEDEXPANSION the character ! becomes a special character. so

ECHO Before the block, %%var%%=%var% and ^^!var^^!=!var!

或

ECHO loop %%i : %%var%%=%var% BUT ^^!var^^!=!var!

追加一个！，字符串 VAR ，另一个单！和 = 和 VAR的运行时间值，因为在分析时，在 ^^ 是 ^ 将所得的 ^！然后$间更换p $在执行时PTED为文字！。在！无功！仍然在分析时完好无损，但由在执行时 VAR 的值替换。

appends a single !, the string var, another single ! and = and the run-time value of var because at PARSE time, the ^^ is replaced by ^ and the resultant ^! is then interpreted at EXECUTION time as a literal !. The !var! remains intact at PARSE time, but is replaced by the value of var at execution time.

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