run macro from command prompt

after some research this is the code that work

# start Excel
$excel = New-Object -comobject Excel.Application

#open file
$FilePath = 'E:z.xlsm'
$workbook = $excel.Workbooks.Open($FilePath)

#make it visible (just to check what is happening)
$excel.Visible = $true

#access the Application object and run a macro
$app = $excel.Application
$app.Run("a")

note : i run this code from Powershell so you have to save it in a '.PS1' file to run it