Set several values as constants
Rename a function
Label functions separately in use
Define function `prompt_password`
Define function `configure_osx`
Define function `install_homebrew_casks`
Define function `install_homebrew_formulae`
Define function `install_homebrew_if_missing`
Define function `install_homebrew_taps`
Define function `update_homebrew_if_exists`
Collect processes
Clear up function `configure_osx`
Clear up function `prompt_password`
Change expression of messages
Clear up execution processes for my readability
Declare variables in functions as `local`
Unify style of blank lines
Put variables declaration to head of each function or block
Rename variables