Git: Check programmatically if anything is staged

Question

For a Git script I'm writing, I'd like to have a programmatic way to check whether there is anything at all staged. i.e. I want a positive result if anything at all is staged, and negative if nothing is staged.

Bonus points: A way to programmatically check whether there is anything new in the working tree that can be staged.

Answer 1

You're looking for:

git diff --cached --quiet

(or replace --quiet with --exit-code if you still want output)

Answer 2

The short format output of the git status (also explained in helppage git status --help) command gives an output that can be used in a programmatic way. From the git status --help helppage (somewhere at the bottom of the page in the "OUTPUT"-section, for my git version 2.8.1.windows.1):

In the short-format, the status of each path is shown as
XY PATH1 -> PATH2
where PATH1 is the path in the HEAD, and the " -> PATH2" part is shown only when PATH1 corresponds to a different path in the index/worktree (i.e. the file is renamed). The XY is a two-letter status code.

According to the same helppage:

For paths with merge conflicts, X and Y show the modification states of each side of the merge. For paths that do not have merge conflicts, X shows the status of the index, and Y shows the status of the work tree. For untracked paths, XY are ??. Other status codes can be interpreted as follows:
' ' = unmodified
M = modified
A = added
D = deleted
R = renamed
C = copied
U = updated but unmerged
Ignored files are not listed, unless --ignored option is in effect, in which case XY are !!.

All this info about the values XY can take can also be found here. The short format is obtained by using git status -s. So

git status -s | grep "^[MADRCU]"

Should give you all entries that have been staged so far. You could add the -c flag to the grep to count the lines instead of printing them.

Bonus: anything new in the working tree that hasn't been staged yet (still untracked) should be found with:

git status -s | grep "^??"

Hope this helps.

Good luck!