A list of git commands that I use regularly and which may be useful:

git diff --cached

stage changes

git add -p

Git add in interactive mode (patch per patch)

git submodule update --init [--recursive]

Update and/or install all submodules (recursively)

git push origin :branch-or-tag-name

Delete remote branch or tag

git log origin/master ^master

Show diff beetween remote and local branch

git br --contains commit

Show in which branch is contained a commit (thx MarcW)

git push origin commit:master

Push master to origin remote until a commit

git co my_file.txt --theirs/--ours

In a merge with conflict, checkout local branch (ours) or other branch (theirs) file version