ref: f88a55e79b5bf656e7f9578d1318a955b9a4963a 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