Git pre-commit hook that detects if the developer forget to remove all the javascript console.log before commit.

gistfile1.sh

#!/bin/sh
# Redirect output to stderr.
exec 1>&2
# enable user input
exec < /dev/tty

consoleregexp='^\+.*console\.log('
# CHECK
if test $(git diff --cached | grep $consoleregexp | wc -l) != 0
then 
  exec git diff --cached | grep -ne $consoleregexp
  read -p "There are some occurrences of console.log at your modification. Are you sure want to continue? (y/n)" yn
  echo $yn | grep ^[Yy]$
  if [ $? -eq 0 ] 
  then
    exit 0; #THE USER WANTS TO CONTINUE
  else
    exit 1; # THE USER DONT WANT TO CONTINUE SO ROLLBACK
  fi
fi

Insert this into your local git repo at .git/hooks/pre-commit and execute the following code, if needed:
chmod +x .git/hooks/pre-commit