The key combination Ctrl + left or right arrow key can be used to go a word left or right in many programs such as GNU Emacs or the bash. In the default configuration of the OS X terminal, this is not the case. That’s because Terminal.app sends the wrong key codes for bash’s default configuration. So you just need to got to the preferences (cmd+,) and set the key codes for Ctrl+left and right to 33b and 33f respectively:
