[文本处理] [讨论]对批处理中set /p命令结合管道或重定向赋值时的几点猜测

@echo off
set var1=
set var2=
rem 第一个set /p尝试从子进程的输入流里面读取1203个字符，取第一个\n之前的字符串赋值给var1
rem 但是总共传进来的字符串太少了，所以没有什么可以留给第二个set /p了（并非子进程过早关闭神马的）
findstr "123" %0 | cmd /v /c "set /p var1=&set var1&set /p var2=&set var2"
rem 123456
pause
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@echo off
set var3=
set var4=
rem 只有当传递给子进程的字符串足够第一个set /p吃饱的时候，第二个set /p才有机会取到值
findstr "abc" %0 | cmd /v /c "set /p var3=&set var3&set /p var4=&set var4"
rem abcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghijabcdefghij
pause
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@echo off
set var5=
set var6=
findstr "xyz" %0 >a.txt
rem 使用重定向的时候，文本内容是传递给整个语句块的
rem 那个for+set /p合并文件的例子也许更加容易理解http://bbs.bathome.net/thread-13327-1-1.html
rem 重定向不是传递给for命令本身，而是传递给整个for语句块
rem 有Shell基础的朋友可以体会一下这个帖子http://bbs.chinaunix.net/thread-3606286-1-1.html
(set /p var5=&set var5&set /p var6=&set var6)<a.txt
rem uvwxyz
pause
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