[git] How to Diff between local uncommitted changes and origin

Let's say I cloned a repository and started modifying files. I know that if I have local uncommitted changes, I can do a diff as follows git diff test.txt and it will show me the difference between the current local HEAD and the modified, uncommitted changes in the file. If I commit those changes I can diff it against the original repository by using git diff master origin/master

But is there any way of diff'ing the local changes with the original repository on the server before committing locally? I tried various permutations of git diff --cached master origin/master with no luck.

I know it's not an answer to the exact question asked, but I found this question looking to diff a file in a branch and a local uncommitted file and I figured I would share

Syntax:

git diff <commit-ish>:./ -- <path>

Examples:

git diff origin/master:./ -- README.md
git diff HEAD^:./ -- README.md
git diff stash@{0}:./ -- README.md
git diff 1A2B3C4D:./ -- README.md

(Thanks Eric Boehs for a way to not have to type the filename twice)

To see non-staged (non-added) changes to existing files

git diff

Note that this does not track new files. To see staged, non-commited changes

git diff --cached

If you want to compare files visually you can use:

git difftool

It will start your diff app automatically for each changed file.

PS: If you did not set a diff app, you can do it like in the example below(I use Winmerge):

git config --global merge.tool winmerge
git config --replace --global mergetool.winmerge.cmd "\"C:\Program Files (x86)\WinMerge\WinMergeU.exe\" -e -u -dl \"Base\" -dr \"Mine\" \"$LOCAL\" \"$REMOTE\" \"$MERGED\""
git config --global mergetool.prompt false