Various ways to check your working tree
$ git diff (1)
$ git diff --cached (2)
$ git diff HEAD (3)
1. Changes in the working tree not yet staged for the next
commit.
2. Changes between the index and your last commit; what you
would be committing if you run git commit without -a option.
3. Changes in the working tree since your last commit; what
you would be committing if you run git commit -a
Comparing with arbitrary commits
$ git diff test (1)
$ git diff HEAD -- ./test (2)
$ git diff HEAD^ HEAD (3)
1. Instead of using the tip of the current branch, compare
with the tip of "test" branch.
2. Instead of comparing with the tip of "test" branch,
compare with the tip of the current branch, but limit the
comparison to the file "test".
3. Compare the version before the last commit and the last
commit.
Comparing branches
$ git diff topic master (1)
$ git diff topic..master (2)
$ git diff topic...master (3)
1. Changes between the tips of the topic and the master
branches.
2. Same as above.
3. Changes that occurred on the master branch since when the
topic branch was started off it.
Limiting the diff output
$ git diff --diff-filter=MRC (1)
$ git diff --name-status (2)
$ git diff arch/i386 include/asm-i386 (3)
1. Show only modification, rename, and copy, but not addition
or deletion.
2. Show only names and the nature of change, but not actual
diff output.
3. Limit diff output to named subtrees.
Munging the diff output
$ git diff --find-copies-harder -B -C (1)
$ git diff -R (2)
1. Spend extra cycles to find renames, copies and complete
rewrites (very expensive).
2. Output diff in reverse.
