diff-dirs

$ mkdir dir1 dir2
$ echo abc > dir1/file
$ echo abc > dir2/file
$ echo def >> dir2/file
$ diff dir1 dir2
diff dir1/file dir2/file
1a2
> def
$ mkdir dir1/sub dir2/sub
$ echo abc > dir1/sub/file
$ echo def >> dir2/sub/file
$ echo abc >> dir2/subfile
$ diff dir1 dir2
diff dir1/file dir2/file
1a2
> def
Common subdirectories: dir1/sub and dir2/sub
Only in dir2: subfile
$ diff -r dir1 dir2
diff -r dir1/file dir2/file
1a2
> def
diff -r dir1/sub/file dir2/sub/file
1c1
< abc
---
> def
Only in dir2: subfile
$