如何“FOR”在cmd批处理文件中工作？ [英] How does "FOR" work in cmd batch file?

问题描述

我已经编程了几十种语言20年，但我永远不能理解为什么FOR工作在windows cmd shell批处理文件，无论我多么努力。我阅读

I've been programming in dozens of languages for 20 years but I could never understand how "FOR" work in windows cmd shell batch file, no matter how hard I tried. I read

http：// www .amazon.com / Windows-Administration-Command-Line-Vista / dp / 0470046163 / ref = sr_1_1？ie = UTF8& s = books& qid = 1241362727& sr = 8-1

http://www.ss64.com/nt/for .html

和其他几个在互联网上的文章，但仍然混淆，不能完成任何事情。

and several other articles on the internet but still confuse and cannot accomplish anything.

对于一个更具体的问题，我如何遍历每个路径在％PATH％变量？
我尝试过

For a little more specific question, how can I iterate through each path in %PATH% variable ? I've tried with

rem showpathenv.bat
for /f "delims=;" %%g in ("%PATH%") do echo %%g

第一个路径，不是所有的。为什么？我做错了什么？

That'd show only the first path, not all of them. Why ? What I do wrong ?

推荐答案

没有答案真的有效。我设法自己找到解决方案。
这有点麻烦，但它解决了我的问题：

None of the answers actually work. I've managed to find the solution myself. This is a bit hackish, but it solve the problem for me:

echo off
setlocal enableextensions
setlocal enabledelayedexpansion
set MAX_TRIES=100
set P=%PATH%
for /L %%a in (1, 1, %MAX_TRIES%) do (
  for /F "delims=;" %%g in ("!P!") do (
    echo %%g
    set P=!P:%%g;=!
    if "!P!" == "%%g" goto :eof
  )
)

$ b b

哦！我讨厌批量文件编程!!

Oh ! I hate batch file programming !!

更新

Mark的解决方案更简单，它不会与包含空格的路径一起工作。这是Mark的解决方案的一个小修改版本

Mark's solution is simpler but it won't work with path containing whitespace. This is a little-modified version of Mark's solution

echo off
setlocal enabledelayedexpansion
set NonBlankPath=%PATH: =#%
set TabbedPath=%NonBlankPath:;= %
for %%g in (%TabbedPath%) do (
  set GG=%%g
  echo !GG:#= !
)

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