How Do I Use evince To Remove The Password?
Open a pdf file using evince itself, enter:evince input.pdfEnter your password. Once opened click on File > Print > Select "Print to file" > Select "PDF" as output format and click on Print.
Writing a shell script left as an exercise to the readers.
REFERENCES
http://www.cyberciti.biz/faq/removing-password-from-pdf-on-linux/