@pan64: Have you ever looked inside a PDF file? The text that gets displayed is not there in plain ASCII.
@Hoxygen232: You will need to write a short script to do what you want:
Code:
#!/bin/bash
String="$1"
shift
for F in "$@"; do
pdftotext "$F" - | grep -H --label="$F" "$String"
done
Put that in a file named "pdfgrep" in some directory in your $PATH and make it executable. Then you can do:
Code:
find /"$DIRECTORY"/ -name '*.pdf' -exec pdfgrep 'palindrom' {} +