为什么在管道块命令中进行“IF"比较时会出现错误消息? [英] Why does the error message appear when `IF` comparison is in the piped block command?

问题描述

我简化了代码.以下三个是工作.

I simplified the code. The following three are work.

for /L %a in (1,1,9) do @(if %a NEQ 0 (echo %a))

&

for /L %a in (1,1,9) do @(if not %a == 0 (echo %a))

&

(for /L %a in (1,1,9) do @(if not %a == 0 (echo %a)))|sort /R

但是下一个没用，

(for /L %a in (1,1,9) do @(if %a NEQ 0 (echo %a)))|sort /R

管道块命令中NEQ的问题是什么?

What's the problem of NEQ in the piped block command?

更简单，

这有效，(if 3 == 3 echo yes)|sort

这不起作用，(if 3 NEQ 2 echo yes)|sort

我的部分代码.

@echo off
setlocal enabledelayedexpansion
set Unx_path=.....inUnxUtils
(
for /F %%a in ('^""%Unx_path%pclip.exe"^|"%Unx_path%sed.exe" -r "s/^^$/none/"^|"%Unx_path%sed.exe" -rf "script_file"^"') do @(
  if not "%%a" == "none" (
    "%Unx_path%grep.exe" -iEe "%%a" "file4search"|"%Unx_path%sed.exe" -r "s/^^[^,]+$/,&/";"s/^^([^.]+)[.][^.]+$/1/"|"%Unx_path%gawk.exe" "BEGIN{FS=",";ORS=" "}{print $2}"|"%Unx_path%sed.exe" "s/%%a//I g";"s/.*/%%a &|/";"s/ -/ /g";"s/ |/
/g";"s/ /	/g";"s/~/	/g"
  ) else (
    echo none
  )
)
)|"%Unx_path%gclip.exe"
exit /b

推荐答案

试试这个:

set "myline=if 3 NEQ 2 echo yes"

( %myLin^e%)|sort

或来自批处理文件(双重扩展与批处理文件和控制台的工作方式不同):

or from batch file (double expansion works differently from batch file and the console):

set "myline=if 3 NEQ 2 echo yes"

( %%myLine%%)|sort

jeb 这里和这里.尽管您在管道之前遇到了问题，但它是相同的错误，因为 cmd 在管道的每一侧创建了两个线程.

The "mystery" was solved by jeb here and here . Though you are facing the issue before the pipe it is the same bug because the cmd creates two threads on each side of the pipe.

for 循环的工作原理如下:

Here's how the for loop can be made to work:

set "line=if %a NEQ 0"
(for /L %a in (1,1,9) do @( %lin^e% echo %a))|sort /R

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