@echo off
for /f "tokens=*" %%a in ('type "C:\Scripts\Tasks\System-Tasks\listing.txt"') do ( 
  for %%b in (%%a) do (
    net localgroup Administrators "%%b" /add
    if errorlevel 1 (
      echo Failed to add %%b to Administrators group.
    ) else (
      echo User %%b added to Administrators group successfully.
    )
  )
)