export your papers to rtf file or get doi list : 

cat Bib2.rtf | sed -e 's/doi:/\'$'\n/g' | grep "^[0-9]" | sed -r "s/.{3}$//" > tmp.txt && cat tmp.txt | awk '{print "https://sci-hub.se/" $0 }' > tmp2.txt && sed G tmp2.txt > new_hub.line.txt