Pdfsandwich is a wrapper that embeds OCR-fonts in scanned PDFs. It uses (currently version 0.1.7) unpaper, which deskews and trims the scanned pages. Unfortunately, unpaper appears to be discontinued, the last update was 2015 . It also occasionally cuts off parts of the text. Luckily, there is an alternative: scantailor.
The shell script in this repo circumvents unpaper, using pdfimages, scantailor and imagemagick to prepare a PDF that is then OCRed by pdfsandwich. It just takes the filename as only argument, like so:
./ocrthispdf testpage.pdf