DOS Copy Command

[marain]

Wanted to copy, changing extension, on all .js files in a folder.
copy *.js *.js1 does not work. (It's been a while.) Any old timers here (or youngsters too) with the answer?

Note: rename does not seem to work either:
rename *.js *.js1

[keyboard]

Hey marain!
rename *.js *.js1 is working as intended for me (on Windows 10).
What operating system are you using? Are you in the right directory?
Any other debugging info you can provide?