How to use wildcard in Windows command-line?

Question

I some animations, they are like this:

/OP/
/OP/OP1/
/OP/OP1/OP1.rmvb
/OP/OP2/
/OP/OP2/OP2.rmvb
/OP/OP3/
/OP/OP3/OP3.rmvb /OP/OP4/
/OP/OP4/OP4.rmvb
...and more

I want to make it like

/OP/
/OP/OP1.rmvb
/OP/OP2.rmvb
/OP/OP3.rmvb
/OP/OP4.rmvb

I tried

move \OP\*\*.rmvb \OP

It gave me error says

The file name, directory name, or volume label syntax is incorrect.

I also tried

dir \OP\*

This shows all the folders

But if I try

dir \OP**

It gave me the same error.

Could anyone please help me?? Thank you very much

Answer 1

Is that a programming question? Requiring to do this on the command line?
Otherwise, I would just do a Windows Search *.rmvb, and drag'n'drop the result to the folder of your choice...