Magento coding standards

You can also try ECG Magento Code Sniffer Coding Standard

Magento best practices are quite good described by Josh Pratt here. He suggests to adopt and follow the Zend Code Style Standards and I can only join him.

The maximal line length is not a strict requirement. However from readability point of view too long lines are not encouraged.

Here are latest Magento marketplace coding standard for Magento1 and Magento2

MEQP2 For Magento2

MEQP1 For Magento1

https://github.com/magento/marketplace-eqp