pdfistxt
A useful script if you wish to programatically manipulate PDF content.
The following script uses the pdffonts and pdftotext commands to find out if there is any text content in a PDF. This is used in my audiobook creation pipeline to see if a PDF requires OCR or not. In Ubuntu you will need to install the packages `xpdf` and `xpdf-utils` to get this to work. I'm sure other distros have xpdf packages too >:3