Substitute multiple lines using sed
echo -e "1\n2\n3"
substitute lines one and two with the word "hello"
echo -e "1\n2\n3" | sed -e '/1/,/2/c hello'
echo -e "1\n2\n3"
substitute lines one and two with the word "hello"
echo -e "1\n2\n3" | sed -e '/1/,/2/c hello'