root@orangepione:/var/www# apt-get install php5 php-pear php5-mysql
Reading package lists... Done
Building dependency tree
Reading state information... Done
Package php5 is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

Package php5-mysql is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'php5' has no installation candidate
E: Package 'php5-mysql' has no installation candidate

Taky nic..