unix - How can I diff two files with full context?

Question

I have two files with slight differences. A normal diff will show me the differences between the files. With -c or -u I can add an amount of context to each hunk. What options can I pass to diff to see every unchanged line alongside the changes, and get the diff as a single, large hunk?

Answer 1

You can also override the diff formatting behavior to get your desired behavior without using side-by-side mode:

diff --new-line-format='+%L' --old-line-format='-%L' --unchanged-line-format=' %L' file1 file2

This command will show you the full file as context and be closest in format to diff -u file1 file2