+++ b/file.txt
@@ -1 +1,2 @@
hello world!
- +hello world, again
++hello world, again
$ git update-index file.txt
$ git diff
------------------------------------------------
+++ b/file.txt
@@ -1 +1,2 @@
hello world!
- +hello world, again
++hello world, again
------------------------------------------------
So "git diff" is comparing against something other than the head.
At this point you should know everything necessary to read the man
pages for any of the git commands; one good place to start would be
-with the commands mentioned in link:everday.html[Everyday git]. You
+with the commands mentioned in link:everyday.html[Everyday git]. You
should be able to find any unknown jargon in the
link:glossary.html[Glosssay].