I am looking for a PDF viewer with some “ruler” functionality to help in reading long paragraphs line by line. I found something similar here but it’s Windows only.
Also, I don’t need it to draw lines as shown, just to help reading line by line. Can someone please suggest something?
Thanks in advance 
I doubt if there is pdf reader with this functionality. You can use KRuler or any other alternative 
This works great, thanks!