bash array的寫法範例

http://go-linux.blogspot.tw/2007/03/basharray.html

http://www.cyberciti.biz/faq/finding-bash-shell-array-length-elements/

http://www.thegeekstuff.com/2010/06/bash-array-tutorial/

http://stackoverflow.com/questions/688849/associative-arrays-in-shell-scripts