How-To get root directory of given path in bash?

Question

My script:

    #!/usr/bin/env bash
    PATH=/home/user/example/foo/bar
    mkdir -p /tmp/backup$PATH

And now I want to get first folder of

Answer 1

Pure bash:

DIR="/home/user/example/foo/bar"
[[ "$DIR" =~ ^[/][^/]+ ]] && printf "$BASH_REMATCH"

Easy to tweak the regex.