this is a messy way to find a git file from the depths of git! change the grep to be some way to identify your file

gistfile1.txt

git prune -n > tmp12312661.txt
sed -i 's/ blob//g' tmp12312661.txt
while read line
do
  git cat-file -p $line | grep "require('simplesmtp')"
  if [ "$?" == "0" ]; then echo $line; fi
done < tmp12312661.txt
rm tmp12312661.txt