Diff

Everything * .

Local (working directory vs. last commit):

git diff HEAD

Between 2 commits/branches/tags:

git diff <commit1|branch1|tag1|HEAD~1> <commit2|branch2|tag2|HEAD>

File

Local (working directory vs. last commit):

git diff HEAD -- hello.txt

Between 2 commits/branches/tags:

git diff <commit1|branch1|tag1|HEAD~1> <commit2|branch2|tag2|HEAD> -- hello.txt

Options

staged changes: --cached `git diff --cached

file names: --name-only git diff --name-only HEAD

add/rm lines: --stat git diff --stat HEAD

word-level: --word-diff git diff --word-diff HEAD

Advanced

git diff <commit_id>..<commit_id> # changes between two commits

git diff <commit_id>...<commit_id> # changes from the common ancestor to the second commit

Who edit what file/line

git blame