To view the PHP version:
php -v

To view the installed php modules:
php -m

To enter an interactive shell:
php -a

To view phpinfo() information:
php -i

To locate the system's php.ini files:
php -i | grep "php.ini"

To start a local webserver for the cwd on port 3000 (requires php >= 5.4):
php -S localhost:3000