I don’t know Mac, but as a Linux user I would tell you to do this:
open the command prompt
type in the command prompt:
find / -name bash
It will look for bash file in your entire disk. If it where found the complete path will be printed.
Then you update your script to use the path returned by find command.
For instance, let me say that bash was found out in /usr/bin. So, find command will print
This would be the path you would use instead of /bin/bash.
If find command didn’t return anything it means you don’t have bash installed.