copy all files in folder, into a folder within that same path

Question

In Linux shell, How can I copy all files from /folder into /folder/sub?

the normal way of copying recursively isn't working (which makes sense) because i'm copying a folder into itself...

Answer 1

cp -a !(sub) sub

You can exclude the sub directory.

From the comments on that similar question:

If this doesn't work, you might need to enable:

shopt -s extglob