Small enchantments

Disclaimer: Haven't used the file, thought these could help  you / others.

I looked in the file as my friend needed help using it. I Though I could add few enchantments while on it.

* I ddn't see any reason to require bash so I changed to sh.
* Commented the api key line, so environment variable can be used..
* Added check to see if parameter was given and that the given argument is file (i.e. not a directory)