# To view the php version:
php -v

# To view the installed php modules:
php -m

# To view phpinfo() information:
php -i

# To lint a php file:
php -l file.php

# To lint all php files within the cwd:
find . -name "*.php" -print0 | xargs -0 -n1 -P8 php -l

# To enter an interactive shell:
php -a

# 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