ref: 40177b86bf5108016fc3a275096e44dc4ada5e9c dir: /sys/src/cmd/diff/test/merge-t5.expected/
1 a b c 2 3 <<<<<<<<<< merge-t5.l 4 x 6 7 ========== original 4 5 6 7 ========== merge-t5.r w x y z >>>>>>>>>> 8 9 10