diff-so-fancy strives to make your diffs human readable instead of machine readable

Changing the second line to: foo.txt text !diff would restore the default unset-ness for diff, while: foo.txt text diff will force diff to be set (both will presumably result in a diff, since Git has presumably not previously been detecting foo.txt as binary).

Normally, git diff looks for non-printable characters in the files and if it looks like the file is likely to be a binary file, it refuses to show the difference. The rationale for that is binary file diffs are not likely to be human readable and will probably mess up your terminal if displayed. However, you can instruct git diff to always treat files as text using the --text option. You can specify this for one diff command: git diff --text HEAD HEAD^ file.txt You can make Git always use this option by setting up a .gitattributes file that contains: file.txt diff

git diff --relative will print paths from the dir you are in.