-s
--suppress-common-lines
Do not print common lines.
-w columns
--width=columns
Use an output width of columns. Note that for historical reasons, this option is -W in diff, -w in sdiff.
$ cat a.txt 1 2 3 4 5 $ cat b.txt 1 2 3a 4 5 $
$ sdiff -s -w 200 a.txt b.txt 3 | 3a $
$ sdiff -w 200 a.txt b.txt 1 1 2 2 3 | 3a 4 4 5 5