Search a keyword in pdf files in a directory

To search for a particular keyword in all pdf files under a directory :
ls *.pdf | xargs -I{} pdftotext {} - | grep -i "keyword"
You can see corresponding lines, but if you want to see file names instead of content, use following statement :
for f in $(find . -name '*.pdf'); do  pdftotext -q $f - | grep -i -q "keyword" && echo $f; done