Install PHPCS and use the Drupal Coding Standard from the coder module.

drupal_phpcs_install.sh

; cd into the directory you store code resources.

cd ~

; Clone PHP_CodeSniffer directly from the github repo.
; You could also install via pear.

git clone [email protected]:squizlabs/PHP_CodeSniffer.git

; Clone the coder branch you want.
; Currently 7.x-2.x has the latest for D7

git clone --branch 7.x-2.x http://git.drupal.org/project/coder.git

; Add the Drupal coding standard to PHPCS.
; Symlink to the Drupal coding standard in the coder module from within
; the PHPCS standards directory.

cd ~/PHP_CodeSniffer/CodeSniffer/Standards/
ln -s ~/coder/coder_sniffer/Drupal/ Drupal

; Get the full path to the phpcs script inorder to configure NetBeans.
cd ~/PHP_CodeSniffer/scripts/

echo $PWD