Windows oneliner在环境变量中设置命令输出

Question

As stated here Is it possible to set an environment variable to the output of a command in cmd.exe I always used that

mycommand.exe>%TEMP%\out.txt
set /P FOO=<%TEMP%\out.txt

But that's ugly because it creates a file.

The for method is better but complicated

I wanted something simple a la unix, like:

mycommand.exe|set /P FOO=

No error, but FOO is not set after I run that.

Why is this not working?

Answer 1

Best way I can think of doing this would be to create your own little batch file that silently uses the FOR construct. For instance, you could create a batch named BatchSet.bat, stored somewhere on your path. The batch would contain the following code:

@Echo off
for /f "delims=" %%i in ('%2') do set %1=%%i
Set %1

If you run this with the following command:

BatchSet MyVar whoami

You'll get something like:

MyVar=servername\John

Obviously, the command you run should limit its output to a single line to be stored properly in the environment variable. For instance, if you run it like this:

BatchSet MyVar Vol

Then you'll only get the first line of the Vol command's output

MyVar= Volume on drive C is labeled MyDisk

But all in all, it's a fairly elegant way of doing what you were looking for.

Note that the last line in the batch is simply there to provide visual output. It can be removed altogether.