Git pre-commit hook to check against accidental describe.only() in tests

pre-commit

#!/bin/bash

# Check for .only() in this path
FOLDER="./webapp/src/js"

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

diffstr=`git diff --cached $against | grep -rnw $FOLDER -e 'describe.only'`
if [[ -n "$diffstr" ]] ; then
    echo "-------------------------------------------------------------------------------"
    echo "You have left describe.only() in test files! Maybe remove it before pushing these changes up?"
    echo "-------------------------------------------------------------------------------"
    grep -rnw $FOLDER -e 'describe.only'
    echo "-------------------------------------------------------------------------------"
    #exit 1
fi