What's the best practice to "git clone" into an existing folder?

This can be done by cloning to a new directory, then moving the .git directory into your existing directory.

If your existing directory is named "code".

git clone https://myrepo.com/git.git temp
mv temp/.git code/.git
rm -rf temp

This can also be done without doing a checkout during the clone command; more information can be found here.

Don't clone, fetch instead. In the repo:

git init
git remote add origin $url_of_clone_source
git fetch origin
git checkout -b master --track origin/master # origin/master is clone's default

Then you can reset the tree to get the commit you want:

git reset origin/master # or whatever commit you think is proper...

and you are like you cloned.

The interesting question here (and the one without answer): How to find out which commit your naked tree was based on, hence to which position to reset to.

The following i did, to checkout master branch in an existing directory:

git init
git remote add origin [my-repo]
git fetch
git checkout origin/master -ft