How do you set environment variables for a single command on Windows?

Question

Is there a way to set environment variables for a single command on Windows like ENVVAR=abc command on Unix?

Variables set by set command on Windows seem to remain for the following commands, but this is not what I want.

Not a duplicate - that other one is specific to CMD, this does not exclude powershell — Gert van den Berg, Apr 20 '21 at 10:01

DavidPostill · Accepted Answer · 2023-04-04T18:53:59.390

52

From the current cmd shell:

You have to clear the variable yourself.

set "ENVVAR=abc" && dir & set ENVVAR=

From a batch file:

You can use setlocal and endlocal.

@echo off
setlocal 
  set "ENVVAR=abc" && dir
endlocal

Use a child cmd shell:

You can use cmd /c to create a child shell.

The variable is set in the child shell and doesn't affect the parent shell (as pointed out in a comment by jpmc26).

cmd /C "set ENVVAR=abc && dir"

An A-Z Index of the Windows CMD command line - An excellent reference for all things Windows cmd line related.
cmd - Start a new CMD shell and (optionally) run a command/executable program.
endlocal - End localisation of environment changes in a batch file. Pass variables from one batch file to another.
redirection - Redirection operators.
set - Display, set, or remove CMD environment variables. Changes made with SET will remain only for the duration of the current CMD session.
setlocal - Set options to control the visibility of environment variables in a batch file.

edited Apr 04 '23 at 18:53

answered Mar 06 '16 at 17:44

DavidPostill

1

Another option is to launch a separate cmd process and set them there. E.g., cmd /C "set ENVVAR=abc && dir". Since it won't affect the parent process, it will be effectively "cleared" on exit. – jpmc26 Mar 06 '16 at 19:48
@jpmc26 Good one. Thanks. Added to answer. – DavidPostill Mar 06 '16 at 20:26
That first method won't clear the variable if the command fails. – nobody Mar 06 '16 at 22:36
@AndrewMedico Thanks. Good point. Answer fixed. – DavidPostill Mar 06 '16 at 22:53
2

Beware: This does not set ENVVAR to the string abc but to abc! The extra space can simply be fixed by leaving it out before the &&. You might want to edit your answer, maybe even explicitly pointing out this issue because it might be surprising for unix affine people. It's extra hard to debug because output of set without any parameters when copied from a cmd.exe window does not include such trailing spaces! – purefanatic Apr 04 '23 at 16:55

1 Answers1