Commands like rm -rf dist make some people uncomfortable because if the were executed from another directory (instead of the directory containing the script) they might remove the wrong dist directory. To get around this people have been inferring the directory containing the script in many different ways, most of them completely wrongly. It turns out that the only safe way to get a safe script root directory is using the POSIX dirname combined with realpath.
dir="$(dirname "$(realpath "$0")")"
Don’t forget to quote everything since this is POSIX shell compatible.