dawei
However if you like you can add a PPA to get those packages anyways:
<span style="font-size:24px;">1.sudo add-apt-repository ppa:ondrej/php</span>
<span style="font-size:24px;">2.sudo apt-get update</span>
<span style="font-size:24px;">3.sudo apt-get install php5.6</span>
