Docker how to transfer files from pc to docker via -v?

Question

Docker

Hello everyone, there is always some problem with transferring files from PC to Docker via -v

docker run --name mongo -v /internalDB:/data/db -d mongo

That is, I transfer from the main folder to the internal folder -- In the data / db folder, all files from the internal folder, no? If so, why don't they move to the ducker?

Answer 1

-v just mounts the folder (rather than copying the data) from the host to docker. judging by what I see, such a folder exists in the docker, so you can’t mount it,
you can do /internalDB:/data/internalDB and then just copy it to where you need