i followed below steps in windows local system first installed xammp

1. cd C:\xampp\php
2. pear install PHP_CodeSniffer pear install --alldeps PHP_CodeSniffer

(if there is any issue run cmd as Administrator)

phpcs -i

3. then to follow Magento coding install magento-ecg/coding-standard throw composer

4. after install it will be in \C:\xampp\htdocs\magento217\vendor\magento-ecg\

5. now run (C:\xampp\php>) phpcs --config-set installed_paths \C:\xampp\htdocs\magento217\vendor\magento-ecg\coding-standard

now it will have all plugins need for M2

phpcs -i

The installed coding standards are PSR1, PSR2, PEAR, MySource, PHPCS, Zend, Squiz, Ecg and EcgM2

i followed below steps in windows local system first installed xammp

1. cd C:\xampp\php
2. pear install PHP_CodeSniffer pear install --alldeps PHP_CodeSniffer

(if there is any issue run cmd as Administrator)

phpcs -i

3. then to follow Magento coding install magento-ecg/coding-standard from composer

4. after install it will be in C:\xampp\htdocs\magento217\vendor\magento-ecg\

5. now run (C:\xampp\php>)

   phpcs --config-set installed_paths C:\xampp\htdocs\magento217\vendor\magento-ecg\coding-standard

now it will have all plugins need for M2

phpcs -i

The installed coding standards are PSR1, PSR2, PEAR, MySource, PHPCS, Zend, Squiz, Ecg and EcgM2

To test Module run below code

C:\xampp\php>phpcs C:\xampp\htdocs\magento217\app\code\NAMESPACE\MODULE_NAME