Git pre-commit hook to add a new line at the end of a file and remove trailing whitespaces

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 [[ "$f" =~ [.](conf|css|erb|html|js|json|log|properties|rb|ru|txt|xml|yml|h|m)$ ]]
    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

I came across strange issue on Ubuntu cause it still complained Syntax error: "(" unexpected (expecting "then") whereas the syntax seems to be just fine.

For those who are not familiar with (yet), Ubuntu has dash as default shell and dash does not support regexp comparison so either change /bin/sh to /bin/bash or change condition into if echo "$f" | egrep -q "[.](conf|css|erb|html|js|json|log|properties|rb|ru|txt|xml|yml|h|m)$".

0/10 can't use on windows

I want to add stuff in the beginning of the file, lets say in each file I want to add, 'Hello this was added at - time'

@jugaldb I am not maintaining the code snippet. I recommend you do some research, create a first script and ask specific questions on Stackoverflow to solve your problem.