pre-commit.sh

#!/bin/sh
#
# An example hook script to verify what is about to be committed.
# Called by "git commit" with no arguments.  The hook should
# exit with non-zero status after issuing an appropriate message if
# it wants to stop the commit.
#
# Usage:
# Remove the .sh file extension when you put the script in your hooks folder!
#
# Purposes: 
# Add an empty line at the end of the file.
# Remove trailing spaces at the end of a line.
# 
# Source: http://eng.wealthfront.com/2011/03/corrective-action-with-gits-pre-commit.html
# Version: 2011-03-08
# Related: http://stackoverflow.com/questions/13223868/how-to-stage-line-by-line-in-git-gui-although-no-newline-at-end-of-file-warnin


# Files (not deleted) in the index
files=$(git diff-index --name-status --cached HEAD | grep -v ^D | cut -c3-)
if [ "$files" != "" ]
then
  for f in $files
  do

    # Only examine known text files
    if [[ "$f" =~ [.](conf|css|sass|less|html|erb|haml|slim|ejs|jade|js|coffee|json|log|properties|rb|ru|txt|xml|yml|h|m|md)$ ]]
    then
      # Add a linebreak to the file if it doesn't have one
      if [ "$(tail -c1 $f)" != '\n' ]
      then
        echo >> $f
        git add $f
      fi

      # Remove trailing whitespace if it exists
      if grep -q "[[:blank:]]$" $f
      then
        sed -i "" -e $'s/[ \t]*$//g' $f
        git add $f
      fi
    fi
  done
fi