Pre commit hook ; flake8 on all python files only

pre-commit.sh

#!/usr/bin/env bash

FILES=`git diff --cached --name-only | grep .py$`
if [ $FILES ]
then
    flake8 --config=./flake8.conf $FILES
    if [ $? != 0 ]
    then
        user=`whoami`
        echo "-- Hey, $user, correct file formating before committing plz"
        exit 1
    else
        echo "flake8 OK"
    fi
fi