lucaswerkmiester wanted the whole hook

pre-commit

#!/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.
#
# To enable this hook, rename this file to "pre-commit".

if git rev-parse --verify HEAD >/dev/null 2>&1
then
        against=HEAD
else
        # Initial commit: diff against an empty tree object
        against=4b825dc642cb6eb9a060e54bf8d69288fbee4904
fi


# If you want to allow non-ascii filenames set this variable to true.
allownonascii=$(git config hooks.allownonascii)

# Cross platform projects tend to avoid non-ascii filenames; prevent
# them from being added to the repository. We exploit the fact that the
# printable range starts at the space character and ends with tilde.
if [ "$allownonascii" != "true" ] &&
        # Note that the use of brackets around a tr range is ok here, (it's
        # even required, for portability to Solaris 10's /usr/bin/tr), since
        # the square bracket bytes happen to fall in the designated range.
        test "$(git diff --cached --name-only --diff-filter=A -z $against |
          LC_ALL=C tr -d '[ -~]\0')"
then
        echo "Error: Attempt to add a non-ascii file name."
        echo
        echo "This can cause problems if you want to work"
        echo "with people on other platforms."
        echo
        echo "To be portable it is advisable to rename the file ..."
        echo
        echo "If you know what you are doing you can disable this"
        echo "check using:"
        echo
        echo "  git config hooks.allownonascii true"
        echo
        exit 1
fi

# If you want to allow filename that differ only by case set this variable to true.
allowcasecollision=$(git config hooks.allowcasecollision)

if [ "$allowcasecollision" != "true" ] &&
        test "$(git diff --cached --name-only | 
          LC_ALL=C tr [A-Z] [a-z] | 
          sort | 
          uniq --repeated )"
then
        echo "Error: Attempt to add a file name which differs only by case from "
        echo "another tracked file"
        echo
        echo "This can cause problems if you want to work"
        echo "with people on other platforms."
        echo
        echo "To be portable it is advisable to rename the file ..."
        echo
        echo "If you know what you are doing you can disable this"
        echo "check using:"
        echo
        echo "  git config hooks.allowcasecollision true"
        echo
        exit 1
fi

exec git diff-index --check --cached $against --