good reads of php, useful tips and self notes
- php class visibility
- function arguments
- constant versus variable
- import in php
- sprintf
- constant vs. definition
use constant inside a class when the constant is script dependent; otherwise, consider definition.
- arrays in php
- argc, argv, getopt
- how to terminate php script
- var_dump
- use variable inside string
- run multi-line hive query in php
- string format
- array_split
For command scripts, use set-up to import new options and avoid use `$this->` when having only a few functions. In addition, should avoid use print_r and use sprintf along with string format.