Change from bash to shell

[divyeshio]

Summary of change

• Changed script file to use shell instead of bash
• Updated Dockerfile to not install bash anymore which resulted in decreased image size

Related issue

Closes #972

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[knjk04]

Hi @divyeshio, thanks so much for creating this PR and for putting effort into changing the shell used.

Unfortunately, I will be archiving this project as I no longer have the time to maintain it. I will close this pull request, but thanks again!