Python 3.x installed, but python UNIX commands starts Python 2.x

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http://stackoverflow.com – I downloaded python 3.3.0 which is latest version and i finished installing now I want to run it in my centOS linux but when i type it in console "python" , python 2.7.0 which is bundled with os installation runs. how can i change it to run 3? I vaguely feel that i have to change the code about path in bin folder or something (HowTos)