Git pre-commit hook to prevent pdf and adoc changes in the same commit

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=$(git hash-object -t tree /dev/null)
fi

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

# Redirect output to stderr.
exec 1>&2

# Just check that pdf and adoc changes are kept in different commits.

HAS_PDF=`git diff --cached --name-status | awk -F "." '{print $NF}' | grep pdf | uniq`
HAS_ADOC=`git diff --cached --name-status | awk -F "." '{print $NF}' | grep adoc | uniq`

[ -n "$HAS_PDF" ] && echo "Changes in pdf:" && git diff --cached --name-status | grep "pdf" | while read f; do echo "  $f"; done
[ -n "$HAS_ADOC" ] && echo "Changes in adoc:" && git diff --cached --name-status | grep "adoc" | while read f; do echo "  $f"; done
if [ -n "$HAS_PDF" ] &&  [ -n "$HAS_ADOC" ]; then
    echo "You should not mix adoc and pdf changes in the same commit message. Plese separate them and try again!"
    exit 1
fi