Como Grep doi do arquivo rtf

v2
cat Bibliography.rtf | sed 's/doi.org\//\n/g' | grep "^[0-9]" | sed -r "s/.{2}$//" > new.txt

v1
cat Bib.rtf | sed -e 's/doi:/\'$'\n/g' | grep "^[0-9]" | sed -r "s/.{3}$//" > new.txt
				^ add new lines			^begin with numbers	 ^remove last 3 characters 		

bib.rtf file was created using zotero 6.
select all > right click > create Bibgraphy > export rft
Hutch Polecat