References: http://ymattw.github.io/bash-scripting-best-practices/#1 http://mywiki.wooledge.org/BashGuide/Practices http://kvz.io/blog/2013/11/21/bash-best-practices/ https://github.com/progrium/bashstyle https://stackoverflow.com/questions/78497/design-patterns-or-best-practices-for-shell-scripts
