thoughtbot/guides — pull request #240 by pbrisbin (2014-11-04 15:03:58+00:00)
Title: Allow using `echo` in simple cases

If (and only if) not passing options, including escapes, or including
variables (which may contain escapes), `echo` will work consistently across
systems.

http://unix.stackexchange.com/questions/65803/why-is-printf-better-than-echo