sdiff file1 file2 -o file3 and everything seems to be going well.
I could enter l or r to choose left or right side content in to the output file.
But for a particular change, I had to edit ...
On MacOS, the sdiff command is described as able to do line-by-line interactive merging, and lists several merge commands for the latest chunk.
e.g. sdiff -o mergefile fileleft fileright
The single ...