How to change multiple file extensions in a folder at once using command prompt

In the below example this would rename all the files in the current directory that end with .bmp to .jpg files.

ren *.bmp* *.jpg*

(ren space *.bmp* space *.jpg*)

Example: you have some "bmp" files in a folder called "test" in "D" drive, then you want to change extension of those "bmp" files to "jpg" then open command prompt then type D:\test>ren *.bmp* *.jpg*

*** No need any additional software to change all files extensions in a folder ***