bash - send email with attachment or empty body with mutt

The mutt is not just an email client, it is also very useful in bash script. mutt's CLI (command line interface) parameter can be called and execute without starting the email client interactively, ideal to run it within bash script to send email. mutt is also able to control from config file, ~/.muttrc, with a rich feature set waiting to harness. Below is one of the possible way to send email with attachment, one or multiple, in a bash script :