Thought I’d mention pdftxt. It translates pdf files to text using libmupdf. Haven’t found anything more lightweight to do the same job. Would be curious if others have. There are some other interesting framebuffer and command line programs at the same site too.
pdftotext is the standard tool to convert PDFs to text. Not sure how lightweight it is but it’s provided by Poppler, together with other amazing utilities such as pdfunite.
I’ve tried pdftotext and a few others. So far, my favorite is the pdftxt program I’ve mentioned.