script under linux tor monitor a directory and ocr pdf files that are saved in it

hi i need a small script, that will monitor a directory for any new pdf file that will be saved in it. if a new file is saved in it it shoud be send to a tesseract ocr install on the same machine and the processed file should be saved in another directory, the original file should just be renamed and kept in a 3rd directory.
the script should run in the background on a linux installation.