Fix typo and imporve echo command in guide/pastebin

[Indosaram]

1. Fix a typo.
2. A string in echo command does not need to be wrapped by double-quotes.

[Indosaram]

Issue #2236

[SergioBenitez]

That's true! But echo "hello world" will do something different than echo "hello. world". I'd rather use the quotes as a result. Thank you!