I created 2 folders: foo and bar.
Both has in it a same.txt which is the same and a diff1.txt which differs.
Both has a buz folder (to test recursivity) and the bars have a same.txt and a diff2.txt.

-> foo/bar
	-> same.txt
	-> diff1.txt
	-> bar
		-> same.txt
		-> diff2.txt

I executed `git diff foo bar` and `git diff --no-index foo bar`. 2 questions I look for ansers now:

- There is zero difference from the outputs. So what's --no-index is?
- They both found the diff for buz/diff2 so is --recursive the default behavior?
Next, I executed `git diff help` and I'm immediately thrown a warning in my face: "warning: Not a git repository. Use --no-index to compare two paths outside a working tree". This makes me conclude that whatever I do --no-index will be needed.
Next I started to investigate your `git diff --recursive --brief from{Build,Google}` suggestion and now I'm realizing it isn't supposed to be "git diff" as neither --recursive nor --brief is a git diff option ("error: unknown option `recursive'")
In fact google doesn't have results for "diff --recursive --brief" so I'm not quite sure wher you got that from?


C:\Users\user\Desktop\delme2>git diff foo bar
diff --git a/foo/buz/diff2.txt b/bar/buz/diff2.txt
index 534e3eb..74454b9 100644
--- a/foo/buz/diff2.txt
+++ b/bar/buz/diff2.txt
@@ -1 +1 @@
-xyz1
\ No newline at end of file
+xyz2
\ No newline at end of file
diff --git a/foo/diff1.txt b/bar/diff1.txt
index da24a33..796740f 100644
--- a/foo/diff1.txt
+++ b/bar/diff1.txt
@@ -1 +1 @@
-abc1
\ No newline at end of file
+abc2
\ No newline at end of file

C:\Users\user\Desktop\delme2>git diff --no-index foo bar
diff --git a/foo/buz/diff2.txt b/bar/buz/diff2.txt
index 534e3eb..74454b9 100644
--- a/foo/buz/diff2.txt
+++ b/bar/buz/diff2.txt
@@ -1 +1 @@
-xyz1
\ No newline at end of file
+xyz2
\ No newline at end of file
diff --git a/foo/diff1.txt b/bar/diff1.txt
index da24a33..796740f 100644
--- a/foo/diff1.txt
+++ b/bar/diff1.txt
@@ -1 +1 @@
-abc1
\ No newline at end of file
+abc2
\ No newline at end of file