FInd files in current directory and grep text and html files - but not index.html and report things that contain the word 'elevator' in four or more lines
find . -type f -print0 | egrep -iazZ '(\.txt|\.html?)$' | grep -vazZ 'index.html' | xargs -n 1 -0 grep -c -Hi elevator | egrep -v ':[0123]$'