Setting and using variable within same command line in Windows cmd.exe

Note that cmd /C "set "EDITOR=vim" && echo %EDITOR%" would not work.
Nor would cmd /C "setlocal ENABLEDELAYEDEXPANSION && set "EDITOR=vim" && echo !EDITOR!"

You would need:

• the /V option, to enable delayed environment variable expansion using ! as delimiter.
• no space between a command and the && (or add quotes)

That is:

C:\> cmd /V /C "set EDITOR=vim&& echo '!EDITOR!'"
'vim'
# or
C:\> cmd /V /C "set "EDITOR=vim" && echo '!EDITOR!'"
'vim'

As noted below by maoizm, it is cmd /V /C, not cmd /C /V (which would not work)

I can't think of any practical reason you'd ever actually want this within the context of a single command

Typically, you need this when you have to replace a value used multiple times in a long command line.
For instance, to deploy a file to Nexus (in multiple lines for readability):

cmd /v /c "set g=com.agroup&& set a=anArtifact&& set v=1.1.0&& \
           mvn deploy:deploy-file -Dfile=C:\path\!a!-!v!.jar \
           -Dpackaging=jar -DgroupId=!g! -DartifactId=!a! -Dversion=!v! \
           -DrepositoryId=nexus 
           -Durl=http://myserver/nexus/content/repositories/my-repo/"

Instead of having to replace group, artifact (used 2 times) and version in a long and complex command line, you can edit them at the beginning of said command. It is clearer/easier to manipulate and change the parameter values.

You can do it in windows like this no need for installing anything.

cmd /C "set EDITOR=vim && set"

You'll see a list of variables and you'll see EDITOR=vim, now run "set" again and it won't be listed.

You can do multiple &&'s to add additional commands:

cmd /C "set EDITOR=vim && do this && do that && otherstuff"

EDIT: /C exits the new cmd right away after running, if you produce output with the new one it will still be visible in the parent window.

You can opt to use /K in which case the new cmd window stays open at the end of the run.

you can use ported util env from package CoreUtils in GnuWin32 http://gnuwin32.sourceforge.net/

1. Setup it
2. Check what directory with env.exe exists in %PATH% variable
3. Use same way like linux version env EDITOR=vim command

Vonc's answer will work for commands that reference the variable as expanded (that is !FOO! instead of %FOO%)

However, It won't work if your command references a regular variable.

For example consider:

some-bat.bat (or any other executable/batch process)

echo %FOO%

And the main process:

set FOO=foo
cmd /V /C "set FOO=bar && some-bat.bat"

Returns foo instead of bar (a second execution would work though)

But still, you could concatenate a new cmd process to force the refresh of the variable.

Like this:

set "FOO=BAR" && cmd /c "echo %FOO%"

Or in case the main command already had to use a new cmd:

cmd /c "set FOO=BAR && cmd /c ^"echo %FOO%^""

I have knocked up a batch file env.cmd which works more or less like the Linux env command:-

echo off
setlocal
for %%f in (%*) do (
  echo %%f|find "=" >nul:
  if errorlevel 1 goto DoCmd
  set %%f
  shift
)
:DoCmd
%1 %2 %3 %4 %5 %6 %7 %8 %9
endlocal

The only difference is that, because of the way cmd parses, the environment assignments need to be quoted, so your command would be:

env "EDITOR=vim" command [up to 8 parameters]

The batch file could be elaborated to remove the 8-parameter restriction by building up the command string within the for loop (delayed expansion will be needed).