Can I use git diff on untracked files?

Question

Is it possible to ask git diff to include untracked files in its diff output, or is my best bet to use git add on the newly created files and the e

Answer 1

I believe you can diff against files in your index and untracked files by simply supplying the path to both files.

git diff --no-index tracked_file untracked_file

Answer 2

With recent git versions you can git add -N the file (or --intent-to-add), which adds a zero-length blob to the index at that location. The upshot is that your "untracked" file now becomes a modification to add all the content to this zero-length file, and that shows up in the "git diff" output.

git diff

echo "this is a new file" > new.txt
git diff

git add -N new.txt
git diff
diff --git a/new.txt b/new.txt
index e69de29..3b2aed8 100644
--- a/new.txt
+++ b/new.txt
@@ -0,0 +1 @@
+this is a new file

Sadly, as pointed out, you can't git stash while you have an --intent-to-add file pending like this. Although if you need to stash, you just add the new files and then stash them. Or you can use the emulation workaround:

git update-index --add --cacheinfo \
100644 e69de29bb2d1d6434b8b29ae775ad8c2e48c5391 new.txt

(setting up an alias is your friend here).

Answer 3

For my interactive day-to-day gitting (where I diff the working tree against the HEAD all the time, and would like to have untracked files included in the diff), add -N/--intent-to-add is unusable, because it breaks git stash.

So here's my git diff replacement. It's not a particularly clean solution, but since I really only use it interactively, I'm OK with a hack:

d() {
    if test "$#" = 0; then
        (
            git diff --color
            git ls-files --others --exclude-standard |
                while read -r i; do git diff --color -- /dev/null "$i"; done
        ) | `git config --get core.pager`
    else
        git diff "$@"
    fi
}

Typing just d will include untracked files in the diff (which is what I care about in my workflow), and d args... will behave like regular git diff.

Notes:

• We're using the fact here that git diff is really just individual diffs concatenated, so it's not possible to tell the d output from a "real diff" -- except for the fact that all untracked files get sorted last.
• The only problem with this function is that the output is colorized even when redirected; but I can't be bothered to add logic for that.
• I couldn't find any way to get untracked files included by just assembling a slick argument list for git diff. If someone figures out how to do this, or if maybe a feature gets added to git at some point in the future, please leave a note here!

Answer 4

Assuming you do not have local commits,

git diff origin/master

Answer 5

For one file:

git diff --no-index /dev/null new_file

For all new files:

for next in $( git ls-files --others --exclude-standard ) ; do git --no-pager diff --no-index /dev/null $next; done;

As alias:

alias gdnew="for next in \$( git ls-files --others --exclude-standard ) ; do git --no-pager diff --no-index /dev/null \$next; done;"

For all modified and new files combined as one command:

{ git --no-pager diff; gdnew }

Answer 6

Not 100% to the point, but if for some reason you don't want to add your files to the index as suggested by the accepted answer, here is another option:

If the files are untracked, obviously the diff is the whole file, so you can just view them with less:

less $(git ls-files --others --exclude-standard)

Navigate between them with :n and :p for next and previous..

Update from the comments: If you need a patch format you can also combine it with git diff:

git ls-files --others --exclude-standard | xargs -n 1 git --no-pager diff /dev/null | less

You can also redirect the output to a file or use an other diff command in this case.