Set command output to env var in batch script

setvar.cmd

@echo off

:: print help
if "%~1" == "--help" (
  type %~dp0setvar.txt

) else (

  :: assign output of command to env var
  for /f "delims=" %%i in ('%~2') do set %~1=%%i

  if "%~3" == "--echo" (
    :: split env var `key=value` and echo value
    for /f "delims== tokens=2" %%g in ('set %~1') do echo %%g
  )
)

setvar.txt

setvar v0.1.0

Unfortunately, `cmd` doesn't have an easy-to-use,
built-in way of assigning the output of a command
to an environment variable.

`setvar` fixes that:

  Usage:
  
    $ setvar <var_name> <command> [--echo]

  Examples:

    $ setvar me whoami
    $ echo %me%
    c-3po\mark

    $ setvar me whoami --echo
    c-3po\mark