如何在Windows命令行（cmd.exe）中使用“for loop”从A到Z驱动有效的驱动器号？
列出驱动器根文件夹中的所有文件的示例应该类似于（概念）：
for %f in (A..Z) do dir %f:\
或近似现有功能：
for /L in (A, Z, 1) do echo %f:\
关闭，但更像是这样。
for %%p in (A B C D E F G H I J K L M N O P Q R S T U V W X Y Z) do if not exist %%p:\nul set FREEDRIVELETTER=%%p
编辑：这是一种powershell方式，不确定是否偏离主题满足您的需求
循环大写字母
65..90 | foreach {[char]$_;Write-Host "Do Something"}
或小写字母
97..122 | foreach {[char]$_;Write-Host "Do Something"}
也许这可以从批处理文件中运行。
@ECHO OFF
start /b /wait powershell.exe "97..122 | foreach {$a=[char]$_ ;dir $a:\}"
PAUSE
我发现的最好方法是使用WMI
wmic卷得到“标题”
只提供有效的驱动器号...仍在寻找一种方法，无需外部工具/库/模块（如WMI）
要在没有明确说明它们的情况下遍历所有驱动器号，您可以使用forfiles（我相信，这是通过Vista的所有Windows版本提供）以及它扩展十六进制的能力。代码0xHH，与exit一起设置exit code和hidden variable =ExitCode将退出代码转换为十六进制值，如下例代码：
@echo off
for /L %%C in (0x41,1,0x5A) do (
cmd /C exit %%C
for /F %%D in ('
forfiles /P "%~dp0." /M "%~nx0" /C "cmd /C echo 0x%%=ExitCode:~-2%%"
') do echo %%D:\
)
虽然这很慢，因为有几个cmd instances打开和关闭。
要遍历所有可用的驱动器，包括网络驱动器以及由subst建立的驱动器，您可以使用以下代码，基于wmic：
for /F "skip=1" %%C in ('wmic LogicalDisk get DeviceID') do for /F %%D in ("%%C") do echo %%D\
要遍历所有本地驱动器，您可以再次使用以下代码，基于wmic：
for /F "skip=1" %%C in ('wmic Volume where "DriveLetter is not Null" get DriveLetter') do for /F %%D in ("%%C") do echo %%D\
要遍历所有本地驱动器，但基于mountvol，您可以使用以下代码：
for /F %%C in ('mountvol ^| find ":\"') do echo %%C
最后，为了完整起见，循环遍历subst建立的所有驱动器，请使用以下代码：
for /F "delims=\" %%C in ('subst') do echo %%C\
要添加到aschipfl的答案，下面是如何以编程方式生成一个字符串变量，其中包含所有用于迭代的字母，（包括上部和下部），尽管它有点笨重：
@ECHO OFF
setlocal enabledelayedexpansion
FOR /F "tokens=1,2" %%a IN ('ECHO 65 90 ^& ECHO 97 122') DO (
FOR /L %%i IN (%%a,1,%%b) DO (cmd /c exit %%i & set alpha=!alpha! !=exitcodeAscii!))
echo %alpha%
pause
我正在努力与findstr一起使用，但它也适用于此。如果您只想生成上部或下部字母，我会将该练习留给读者。以这种方式生成字符串后，您可以在aschipfl的答案中使用该变量：
for %%p in (%alpha%) do if not exist %%p:\nul set FREEDRIVELETTER=%%p
在这里，您可以使用for循环遍历所有驱动器。
@echo off
setlocal enableDelayedExpansion
cls
REM getting the output from fsutil fsinfo drives and putting it in the ogdrives variable
FOR /F "tokens=* USEBACKQ" %%F IN (`fsutil fsinfo drives`) DO (
SET ogdrives=%%F
)
REM making the drives variable the same as the ogdrives variable so it can be manipulated
set drives=!ogdrives!
REM formating the out so that it looks like 1+1+1+... for every drive that is connected
set drives=!drives:Drives^: =!
set drives=!drives:^:\=1!
set drives=!drives: =+!
REM still formating to find out how many drives there are, this bit gets rid of any letters there are
set charms=0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ
for /L %%N in (10 1 62) do (
for /F %%C in ("!charms:~%%N,1!") do (
set drives=!drives:%%C=!
)
)
REM last for finding out the number, this removes the last characters since it is a leading + that shouldnt be there
set drives=!drives:~0,-1!
REM num is now the variable that contains the number of drives connected
set /a num=!drives!
REM reseting the drives variable to the original output so it can be manipulated again
set drives=!ogdrives!
REM this time it is being formated to list the drives as a solid string of drive letters like ABCD
set drives=!drives:Drives^: =!
set drives=!drives:^:\=!
set drives=!drives: =!
REM this is to iterate through that string of drive letters to seperate it into multiple single letter variables that are correlated to a number so they can be used later
:loop
REM the iter variable holds how many times this has looped so that when it hits the final drive it can exit
set /a iter=!iter!+1
REM the pos variable is the position in the string of drive letters that needs to be taken out for this iteration
set /a pos=!iter!-1
REM this sets the driveX variable where X is the drives correlated number to the letter of that drive from the long string of drive letters by using the pos variable
set drive!iter!=!drives:~%pos%,1!
REM this is checking to see if all drives have been assigned a number and if it has it will exit the loop
if !iter!==!num! goto oloop
goto loop
:oloop
REM drives are stored in variables %driveX% where X represents the drive number
REM the number of drives are stored in the %num% variable
REM below is an example for iterating through drives
REM this is an example of how to use the information gathered to iterate through the drives
REM we are using a for loop from 1 to the number of drives connected
for /L %%n in (1 1 !num!) do (
REM for every drive that is connected this will be ran
REM %%n contains a number which will increase since its a for loop
REM the drive driveX variable can then be used since drive1=A and drive2=B etc
echo drive %%n is !drive%%n!
REM you can see how i have embedded a variable inside a variable to create an array of sorts.
)
pause
exit
REM the actual variable names are drive1 drive2 drive3 but so that we can iterate through them we can just use a for loop and put the number in the variable
REM one way you can use this is with the where command since it will only search one drive at a time
REM you can do this like this
for /L %%n in (1 1 !num!) do (
where /R !drive%%n!:\ *.txt
)
REM this will return a list of all txt files in the entire system since it searches all drives.