为什么延迟扩展失败时，在管道内的代码块？

Question

为什么延迟扩展失败时，在管道内的代码块？

下面是一个简单的批处理文件，它演示了如果延迟扩展是在被管道传输的块内，那么延迟扩展是如何失败的。(失败在脚本的末尾)有人能解释为什么会这样吗？

我有一个工作，但它需要创建一个临时文件。我最初是在工作时遇到这个问题的。在Windows批处理文件中查找文件并按大小排序

@echo off
setlocal enableDelayedExpansion

set test1=x
set test2=y
set test3=z

echo(

echo NORMAL EXPANSION TEST
echo Unsorted works
(
  echo %test3%
  echo %test1%
  echo %test2%
)
echo(
echo Sorted works
(
  echo %test3%
  echo %test1%
  echo %test2%
) | sort

echo(
echo ---------
echo(

echo DELAYED EXPANSION TEST
echo Unsorted works
(
  echo !test3!
  echo !test1!
  echo !test2!
)
echo(
echo Sorted fails
(
  echo !test3!
  echo !test1!
  echo !test2!
) | sort
echo(
echo Sort workaround
(
  echo !test3!
  echo !test1!
  echo !test2!
)>temp.txt
sort temp.txt
del temp.txt

以下是结果

NORMAL EXPANSION TEST
Unsorted works
z
x
y

Sorted works
x
y
z

---------

DELAYED EXPANSION TEST
Unsorted works
z
x
y

Sorted fails
!test1!
!test2!
!test3!

Sort workaround
x
y
z

Answer 1

正如Aacini所显示的，似乎许多事情都是在管道中失败的。echo&nbsp;hello&nbsp;|&nbsp;set&nbsp;/p&nbsp;var= echo&nbsp;here&nbsp;|&nbsp;call&nbsp;:function但在现实中，理解管道的工作原理只是一个问题。管道的每一端都在自己的刻板时间线程中启动自己的cmd.exe。这就是为什么如此多的东西似乎被打破的原因。但是有了这些知识，你就可以避免这种情况，创造新的效果。echo&nbsp;one&nbsp;|&nbsp;(&nbsp;set&nbsp;/p&nbsp;varX=&nbsp;&&nbsp;set&nbsp;varX&nbsp;) set&nbsp;var1=var2 set&nbsp;var2=content&nbsp;of&nbsp;two echo&nbsp;one&nbsp;|&nbsp;(&nbsp;echo&nbsp;%%%var1%%%&nbsp;) echo&nbsp;three&nbsp;|&nbsp;echo&nbsp;MYCMDLINE&nbsp;%%cmdcmdline%% echo&nbsp;four&nbsp;&nbsp;|&nbsp;(cmd&nbsp;/v:on&nbsp;/c&nbsp;&nbsp;echo&nbsp;4:&nbsp;!var2!)编辑：深度分析如Dbenham所示，管道的两侧对于膨胀阶段都是等效的。主要规则似乎是：正常的批处理解析器阶段已经完成。.。百分比膨胀.。特殊字符相位/块开始检测.。延迟扩展(但只在启用延迟扩展且不是命令块的情况下)启动cmd.exeC:\Windows\system32\cmd.exe &nbsp;/S /D /c"<BATCH COMMAND>"这些扩展遵循cmd行解析器的规则，而不是批处理行解析器的规则。.。百分比膨胀.。延迟扩展(但前提是启用延迟扩展)这个<BATCH COMMAND>如果它在圆括号块内，将被修改。( echo&nbsp;one&nbsp;%%cmdcmdline%% echo&nbsp;two )&nbsp;|&nbsp;more被称为C:\Windows\system32\cmd.exe &nbsp;/S /D /c" ( echo one %cmdcmdline% & echo two )"，所有新行都更改为&接线员。为什么延迟的扩张阶段会受到括号的影响？我想，它不能在批处理解析器阶段展开，因为块可以由许多命令组成，延迟扩展在执行一行时生效。( set&nbsp;var=one echo&nbsp;!var! set&nbsp;var=two )&nbsp;|&nbsp;more显然!var!不能在批处理上下文中计算，因为这些行仅在cmd行上下文中执行。但是为什么在这种情况下可以在批处理上下文中评估它呢？echo&nbsp;!var!&nbsp;|&nbsp;more在我看来，这是一种“错误”或不和谐的行为，但这不是第一次编辑：添加LF技巧正如dbenham所显示的，cmd行为似乎存在一些限制，即将所有行提要更改为&.( &nbsp;&nbsp;echo&nbsp;7:&nbsp;part1 &nbsp;&nbsp;rem&nbsp;This&nbsp;kills&nbsp;the&nbsp;entire&nbsp;block&nbsp;because&nbsp;the&nbsp;closing&nbsp;)&nbsp;is&nbsp;remarked! &nbsp;&nbsp;echo&nbsp;part2 )&nbsp;|&nbsp;more这导致C:\Windows\system32\cmd.exe &nbsp;/S /D /c" ( echo 7: part1 & rem This ...& echo part2 ) "这个rem会注意到整条线尾，所以连最后的括号也没有了。但是，您可以通过嵌入您自己的行提要来解决这个问题！set&nbsp;LF=^ REM&nbsp;The&nbsp;two&nbsp;empty&nbsp;lines&nbsp;above&nbsp;are&nbsp;required ( &nbsp;&nbsp;echo&nbsp;8:&nbsp;part1 &nbsp;&nbsp;rem&nbsp;This&nbsp;works&nbsp;as&nbsp;it&nbsp;splits&nbsp;the&nbsp;commands&nbsp;%%LF%%&nbsp;echo&nbsp;part2&nbsp;&nbsp; )&nbsp;|&nbsp;more这导致C:\Windows\system32\cmd.exe &nbsp;/S /D /c" ( echo 8: part1 %cmdcmdline% & rem This works as it splits the commands %LF% echo part2 &nbsp;)"当解析器在解析括号时展开%lf%时，生成的代码如下所示(&nbsp;echo&nbsp;8:&nbsp;part1&nbsp;&&nbsp;rem&nbsp;This&nbsp;works&nbsp;as&nbsp;it&nbsp;splits&nbsp;the&nbsp;commands&nbsp; &nbsp;&nbsp;echo&nbsp;part2&nbsp;&nbsp;)这，这个%LF%行为总是在括号内工作，在批处理文件中也是如此。但不是在“正常”线上，有一个<linefeed>将停止对这一行的解析。编辑：异步不是全部事实我说过这两个线程都是异步的，通常是这样的。但实际上，当右线程没有使用管道数据时，左线程可以锁定自己。“管道”缓冲区中似乎有1000个字符的限制，然后线程被阻塞，直到数据被消耗为止。@echo&nbsp;off ( &nbsp;&nbsp;&nbsp;&nbsp;( &nbsp;&nbsp;&nbsp;&nbsp;for&nbsp;/L&nbsp;%%a&nbsp;in&nbsp;(&nbsp;1,1,60&nbsp;)&nbsp;DO&nbsp;( &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;A&nbsp;long&nbsp;text&nbsp;can&nbsp;lock&nbsp;this&nbsp;thread &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;Thread1&nbsp;#####&nbsp;%%a&nbsp;>&nbsp;con &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;) &nbsp;&nbsp;&nbsp;&nbsp;) &nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;Thread1&nbsp;#####&nbsp;end&nbsp;>&nbsp;con )&nbsp;|&nbsp;( &nbsp;&nbsp;&nbsp;&nbsp;for&nbsp;/L&nbsp;%%n&nbsp;in&nbsp;(&nbsp;1,1,6)&nbsp;DO&nbsp;@( &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;ping&nbsp;-n&nbsp;2&nbsp;localhost&nbsp;>&nbsp;nul &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;echo&nbsp;Thread2&nbsp;.....&nbsp;%%n &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;set&nbsp;/p&nbsp;x= &nbsp;&nbsp;&nbsp;&nbsp;) )

Answer 2

我不确定我是应该编辑我的问题，还是把它作为答案发布。我已经模糊地知道，管道在自己的cmd.exe“会话”中同时执行左侧和右侧。但是Aacini和Jeb的回答迫使我认真思考和调查管道的情况。(感谢Jeb演示了当管道进入SET/P时发生了什么！)我开发了这个调查脚本-它帮助解释了很多，但也演示了一些奇怪和意外的行为。我将发布脚本，然后是输出。最后，我将提供一些分析。@echo&nbsp;off cls setlocal&nbsp;disableDelayedExpansion set&nbsp;var1=value1 set&nbsp;"var2=" setlocal&nbsp;enableDelayedExpansion echo&nbsp;on @echo&nbsp;NO&nbsp;PIPE&nbsp;-&nbsp;delayed&nbsp;expansion&nbsp;is&nbsp;ON echo&nbsp;1:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2! (echo&nbsp;2:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2!) @echo( @echo&nbsp;PIPE&nbsp;LEFT&nbsp;SIDE&nbsp;-&nbsp;Delayed&nbsp;expansion&nbsp;is&nbsp;ON echo&nbsp;1L:&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;!var2!&nbsp;|&nbsp;more (echo&nbsp;2L:&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;!var2!)&nbsp;|&nbsp;more (setlocal&nbsp;enableDelayedExpansion&nbsp;&&nbsp;echo&nbsp;3L:&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;!var2!)&nbsp;|&nbsp;more (cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;4L:&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;!var2!)&nbsp;|&nbsp;more cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;5L:&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;!var2!&nbsp;|&nbsp;more @endlocal @echo( @echo&nbsp;Delayed&nbsp;expansion&nbsp;is&nbsp;now&nbsp;OFF (cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;6L:&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;!var2!)&nbsp;|&nbsp;more cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;7L:&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;!var2!&nbsp;|&nbsp;more @setlocal&nbsp;enableDelayedExpansion @echo( @echo&nbsp;PIPE&nbsp;RIGHT&nbsp;SIDE&nbsp;-&nbsp;delayed&nbsp;expansion&nbsp;is&nbsp;ON echo&nbsp;junk&nbsp;|&nbsp;echo&nbsp;1R:&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;!var2! echo&nbsp;junk&nbsp;|&nbsp;(echo&nbsp;2R:&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;!var2!) echo&nbsp;junk&nbsp;|&nbsp;(setlocal&nbsp;enableDelayedExpansion&nbsp;&&nbsp;echo&nbsp;3R:&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;!var2!) echo&nbsp;junk&nbsp;|&nbsp;(cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;4R:&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;!var2!) echo&nbsp;junk&nbsp;|&nbsp;cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;5R:&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;!var2! @endlocal @echo( @echo&nbsp;Delayed&nbsp;expansion&nbsp;is&nbsp;now&nbsp;OFF echo&nbsp;junk&nbsp;|&nbsp;(cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;6R:&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;!var2!) echo&nbsp;junk&nbsp;|&nbsp;cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;7R:&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;!var2!这是输出NO&nbsp;PIPE&nbsp;-&nbsp;delayed&nbsp;expansion&nbsp;is&nbsp;ON C:\test>echo&nbsp;1:&nbsp;value1,&nbsp;,&nbsp;!var1!,&nbsp;!var2! 1:&nbsp;value1,&nbsp;,&nbsp;value1, C:\test>(echo&nbsp;2:&nbsp;value1,&nbsp;,&nbsp;!var1!,&nbsp;!var2!&nbsp;) 2:&nbsp;value1,&nbsp;,&nbsp;value1, PIPE&nbsp;LEFT&nbsp;SIDE&nbsp;-&nbsp;Delayed&nbsp;expansion&nbsp;is&nbsp;ON C:\test>echo&nbsp;1L:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2!&nbsp;&nbsp;&nbsp;|&nbsp;more 1L:&nbsp;value1,&nbsp;%var2%,&nbsp;value1, C:\test>(echo&nbsp;2L:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2!&nbsp;)&nbsp;&nbsp;|&nbsp;more 2L:&nbsp;value1,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2! C:\test>(setlocal&nbsp;enableDelayedExpansion&nbsp;&nbsp;&nbsp;&&nbsp;echo&nbsp;3L:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2!&nbsp;)&nbsp;&nbsp;|&nbsp;more 3L:&nbsp;value1,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2! C:\test>(cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;4L:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2!&nbsp;)&nbsp;&nbsp;|&nbsp;more 4L:&nbsp;value1,&nbsp;%var2%,&nbsp;value1,&nbsp;!var2! C:\test>cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;5L:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2!&nbsp;&nbsp;&nbsp;|&nbsp;more 5L:&nbsp;value1,&nbsp;%var2%,&nbsp;value1, Delayed&nbsp;expansion&nbsp;is&nbsp;now&nbsp;OFF C:\test>(cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;6L:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2!&nbsp;)&nbsp;&nbsp;|&nbsp;more 6L:&nbsp;value1,&nbsp;%var2%,&nbsp;value1,&nbsp;!var2! C:\test>cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;7L:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2!&nbsp;&nbsp;&nbsp;|&nbsp;more 7L:&nbsp;value1,&nbsp;%var2%,&nbsp;value1,&nbsp;!var2! PIPE&nbsp;RIGHT&nbsp;SIDE&nbsp;-&nbsp;delayed&nbsp;expansion&nbsp;is&nbsp;ON C:\test>echo&nbsp;junk&nbsp;&nbsp;&nbsp;|&nbsp;echo&nbsp;1R:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2! 1R:&nbsp;value1,&nbsp;%var2%,&nbsp;value1, C:\test>echo&nbsp;junk&nbsp;&nbsp;&nbsp;|&nbsp;(echo&nbsp;2R:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2!&nbsp;) 2R:&nbsp;value1,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2! C:\test>echo&nbsp;junk&nbsp;&nbsp;&nbsp;|&nbsp;(setlocal&nbsp;enableDelayedExpansion&nbsp;&nbsp;&nbsp;&&nbsp;echo&nbsp;3R:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2!&nbsp;) 3R:&nbsp;value1,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2! C:\test>echo&nbsp;junk&nbsp;&nbsp;&nbsp;|&nbsp;(cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;4R:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2!&nbsp;) 4R:&nbsp;value1,&nbsp;%var2%,&nbsp;value1,&nbsp;!var2! C:\test>echo&nbsp;junk&nbsp;&nbsp;&nbsp;|&nbsp;cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;5R:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2! 5R:&nbsp;value1,&nbsp;%var2%,&nbsp;value1, Delayed&nbsp;expansion&nbsp;is&nbsp;now&nbsp;OFF C:\test>echo&nbsp;junk&nbsp;&nbsp;&nbsp;|&nbsp;(cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;6R:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2!&nbsp;) 6R:&nbsp;value1,&nbsp;%var2%,&nbsp;value1,&nbsp;!var2! C:\test>echo&nbsp;junk&nbsp;&nbsp;&nbsp;|&nbsp;cmd&nbsp;/v:on&nbsp;/c&nbsp;echo&nbsp;7R:&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var2! 7R:&nbsp;value1,&nbsp;%var2%,&nbsp;value1,&nbsp;!var2!我测试了管道的左侧和右侧，以证明处理是对称的。测试1和2表明，在正常批处理情况下，括号对延迟扩展没有任何影响。测试1L，1R：延迟扩张如预期一样有效。Var2是未定义的，所以%var2%和！var2！输出显示这些命令是在命令行上下文中执行的，而不是在批处理上下文中执行的。换句话说，使用命令行解析规则代替批处理解析。(见Windows命令解释器(cmd.exe)如何解析脚本？)&nbsp;编辑-！VAR 2！在父批处理上下文中展开。测试2L，2R：括号禁用延迟扩展！我心里很奇怪也很意外。编辑-Jeb认为这是一个MS错误或设计缺陷。我同意，不一致的行为似乎没有任何合理的理由测试3L，3R：&nbsp;setlocal EnableDelayedExpansion不起作用。但这是预期的，因为我们处于命令行上下文中。setlocal只在批处理上下文中工作。测试4L，4R：延迟扩展最初启用，但括号禁用它。CMD /V:ON重新启用延迟扩展，一切都按预期进行。我们仍然有命令行上下文，输出和预期的一样。测试5L，5R：几乎与4L一样，除了延迟扩展之外，在以下情况下已启用了4R：CMD /V:on被处决了。%var2%提供预期的命令行上下文输出。但是！变了！输出为空白，这在批处理上下文中是预期的。这是另一个非常奇怪和意外的行为。编辑-实际上这是有意义的，现在我知道了！变种2！在父批处理上下文中展开。测试6L，6R，7L，7R：这些类似于测试4L/R，5L/R，除了现在延迟扩展开始禁用。这一次，所有4种场景都给出了预期的！var2！批处理上下文输出。如果有人能为2L，2R和5L，5R的结果提供一个合乎逻辑的解释，那么我将选择它作为我最初问题的答案。否则，我可能会接受这个帖子作为答案(实际上更多的是观察发生了什么，而不是回答)。刺死它了！增编：作为对Jeb的评论的回应，这里有更多的证据表明，在命令行上下文中，而不是在批处理上下文中，命令在批处理中执行。这个批处理脚本：@echo&nbsp;on call&nbsp;echo&nbsp;batch&nbsp;context&nbsp;%%%% call&nbsp;echo&nbsp;cmd&nbsp;line&nbsp;context&nbsp;%%%%&nbsp;|&nbsp;more给出这个输出：C:\test>call&nbsp;echo&nbsp;batch&nbsp;context&nbsp;%% batch&nbsp;context&nbsp;% C:\test>call&nbsp;echo&nbsp;cmd&nbsp;line&nbsp;context&nbsp;%%&nbsp;&nbsp;&nbsp;|&nbsp;more cmd&nbsp;line&nbsp;context&nbsp;%%最后增编我增加了一些额外的测试和结果，以证明到目前为止的所有发现。我还演示了可变膨胀发生在管道处理之前。最后，我展示了管道处理的一些有趣的副作用，当多行块被折叠成一行时。@echo&nbsp;off cls setlocal&nbsp;disableDelayedExpansion set&nbsp;var1=value1 set&nbsp;"var2=" setlocal&nbsp;enableDelayedExpansion echo&nbsp;on @echo( @echo&nbsp;Delayed&nbsp;expansion&nbsp;is&nbsp;ON echo&nbsp;1:&nbsp;%%,&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;^^^!var1^^^!,&nbsp;!var2!,&nbsp;^^^!var2^^^!,&nbsp;%%cmdcmdline%%&nbsp;|&nbsp;more (echo&nbsp;2:&nbsp;%%,&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;^^^!var1^^^!&nbsp;!var2!,&nbsp;%%cmdcmdline%%)&nbsp;|&nbsp;more for&nbsp;%%a&nbsp;in&nbsp;(Z)&nbsp;do&nbsp;(echo&nbsp;3:&nbsp;%%a&nbsp;%%,&nbsp;%%var1%%,&nbsp;%%var2%%,&nbsp;!var1!,&nbsp;^^^!var1^^^!&nbsp;!var2!,&nbsp;%%cmdcmdline%%)&nbsp;|&nbsp;more ( &nbsp;&nbsp;echo&nbsp;4:&nbsp;part1 &nbsp;&nbsp;set&nbsp;"var2=var2Value &nbsp;&nbsp;set&nbsp;var2 &nbsp;&nbsp;echo&nbsp;" &nbsp;&nbsp;set&nbsp;var2 ) ( &nbsp;&nbsp;echo&nbsp;5:&nbsp;part1 &nbsp;&nbsp;set&nbsp;"var2=var2Value &nbsp;&nbsp;set&nbsp;var2 &nbsp;&nbsp;echo&nbsp;" &nbsp;&nbsp;set&nbsp;var2 &nbsp;&nbsp;echo&nbsp;---&nbsp;begin&nbsp;cmdcmdline&nbsp;--- &nbsp;&nbsp;echo&nbsp;%%cmdcmdline%% &nbsp;&nbsp;echo&nbsp;---&nbsp;end&nbsp;cmdcmdline&nbsp;--- )&nbsp;|&nbsp;more ( &nbsp;&nbsp;echo&nbsp;6:&nbsp;part1 &nbsp;&nbsp;rem&nbsp;Only&nbsp;this&nbsp;line&nbsp;remarked &nbsp;&nbsp;echo&nbsp;part2 ) ( &nbsp;&nbsp;echo&nbsp;7:&nbsp;part1 &nbsp;&nbsp;rem&nbsp;This&nbsp;kills&nbsp;the&nbsp;entire&nbsp;block&nbsp;because&nbsp;the&nbsp;closing&nbsp;)&nbsp;is&nbsp;remarked! &nbsp;&nbsp;echo&nbsp;part2 )&nbsp;|&nbsp;more这是输出Delayed&nbsp;expansion&nbsp;is&nbsp;ON C:\test>echo&nbsp;1:&nbsp;%,&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;^!var1^!,&nbsp;!var2!,&nbsp;^!var2^!,&nbsp;%cmdcmdline%&nbsp;&nbsp;&nbsp;|&nbsp;more 1:&nbsp;%,&nbsp;value1,&nbsp;%var2%,&nbsp;value1,&nbsp;!var1!,&nbsp;,&nbsp;!var2!,&nbsp;C:\Windows\system32\cmd.exe&nbsp;&nbsp;/S&nbsp;/D&nbsp;/c"&nbsp;echo&nbsp;1:&nbsp;%,&nbsp;%var1%,&nbsp;%var2%,&nbsp;value1,&nbsp;!var1!,&nbsp;,&nbsp;!var2!,&nbsp;%cmdcmdline%&nbsp;" C:\test>(echo&nbsp;2:&nbsp;%,&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;^!var1^!&nbsp;!var2!,&nbsp;%cmdcmdline%&nbsp;)&nbsp;&nbsp;|&nbsp;more 2:&nbsp;%,&nbsp;value1,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var1!&nbsp;!var2!,&nbsp;C:\Windows\system32\cmd.exe&nbsp;&nbsp;/S&nbsp;/D&nbsp;/c"&nbsp;(&nbsp;echo&nbsp;2:&nbsp;%,&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;^!var1^!&nbsp;!var2!,&nbsp;%cmdcmdline%&nbsp;)" C:\test>for&nbsp;%a&nbsp;in&nbsp;(Z)&nbsp;do&nbsp;(echo&nbsp;3:&nbsp;%a&nbsp;%,&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;^!var1^!&nbsp;!var2!,&nbsp;%cmdcmdline%&nbsp;)&nbsp;&nbsp;|&nbsp;more C:\test>(echo&nbsp;3:&nbsp;Z&nbsp;%,&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;^!var1^!&nbsp;!var2!,&nbsp;%cmdcmdline%&nbsp;)&nbsp;&nbsp;|&nbsp;more 3:&nbsp;Z&nbsp;%,&nbsp;value1,&nbsp;%var2%,&nbsp;!var1!,&nbsp;!var1!&nbsp;!var2!,&nbsp;C:\Windows\system32\cmd.exe&nbsp;&nbsp;/S&nbsp;/D&nbsp;/c"&nbsp;(&nbsp;echo&nbsp;3:&nbsp;Z&nbsp;%,&nbsp;%var1%,&nbsp;%var2%,&nbsp;!var1!,&nbsp;^!var1^!&nbsp;!var2!,&nbsp;%cmdcmdline%&nbsp;)" C:\test>( echo&nbsp;4:&nbsp;part1 &nbsp;set&nbsp;"var2=var2Value &nbsp;set&nbsp;var2 &nbsp;echo&nbsp;" &nbsp;set&nbsp;var2 ) 4:&nbsp;part1 var2=var2Value " var2=var2Value C:\test>( echo&nbsp;5:&nbsp;part1 &nbsp;set&nbsp;"var2=var2Value &nbsp;set&nbsp;var2 &nbsp;echo&nbsp;" &nbsp;set&nbsp;var2 &nbsp;echo&nbsp;---&nbsp;begin&nbsp;cmdcmdline&nbsp;--- &nbsp;echo&nbsp;%cmdcmdline% &nbsp;echo&nbsp;---&nbsp;end&nbsp;cmdcmdline&nbsp;--- )&nbsp;&nbsp;|&nbsp;more 5:&nbsp;part1 var2=var2Value&nbsp;&&nbsp;set&nbsp;var2&nbsp;&&nbsp;echo ---&nbsp;begin&nbsp;cmdcmdline&nbsp;--- C:\Windows\system32\cmd.exe&nbsp;&nbsp;/S&nbsp;/D&nbsp;/c"&nbsp;(&nbsp;echo&nbsp;5:&nbsp;part1&nbsp;&&nbsp;set&nbsp;"var2=var2Value var2=var2Value&nbsp;&&nbsp;set&nbsp;var2&nbsp;&&nbsp;echo "&nbsp;&&nbsp;set&nbsp;var2&nbsp;&&nbsp;echo&nbsp;---&nbsp;begin&nbsp;cmdcmdline&nbsp;---&nbsp;&&nbsp;echo&nbsp;%cmdcmdline%&nbsp;&&nbsp;echo&nbsp;---&nbsp;end&nbsp;cmdcmdline&nbsp;---&nbsp;)" ---&nbsp;end&nbsp;cmdcmdline&nbsp;--- C:\test>( echo&nbsp;6:&nbsp;part1 &nbsp;rem&nbsp;Only&nbsp;this&nbsp;line&nbsp;remarked &nbsp;echo&nbsp;part2 ) 6:&nbsp;part1 part2 C:\test>(echo&nbsp;%cmdcmdline%&nbsp;&nbsp;&nbsp;&&nbsp;( echo&nbsp;7:&nbsp;part1 &nbsp;rem&nbsp;This&nbsp;kills&nbsp;the&nbsp;entire&nbsp;block&nbsp;because&nbsp;the&nbsp;closing&nbsp;)&nbsp;is&nbsp;remarked! &nbsp;echo&nbsp;part2 )&nbsp;)&nbsp;&nbsp;|&nbsp;more测试1：2：总结所有的行为，%cmdcmdline%技巧确实有助于演示正在发生的事情。测试3：演示变量展开仍然适用于管道块。测试4：/5：和6：/7：显示管道与多行块的工作方式的有趣的副作用。小心！我必须相信，在复杂的管道场景中找出转义序列将是一场噩梦。