entrypoint.bash is non-compliant with Shell Style Guide

I was reviewing https://github.com/google/osv.dev/pull/1017 which has a straight copy of `entrypoint.bash` from this repo, and it's not particularly compliant (or internally consistent) with https://google.github.io/styleguide/shellguide.html (see some of my comments on that PR).

You might like to do something about that.

Locate the repository's entrypoint.bash and compare it with the linked Shell Style Guide and the referenced pull request 1017 comments. Done means the script is internally consistent and conforms to the relevant style guidance, with any behavior preserved.

Written by the indexing model from the issue text.