git "ping": check if remote repository exists

I think the git ls-remote command is pretty much made for that purpose.

If you use --exit-code argument you can skip sending output to null. It will return something only in case of error.

Also, you can use -h argument to show only heads references.

git ls-remote --exit-code -h "$REPO_URL"

You can narrow output by using something like git ls-remote "$REPO_URL" HEAD