diff --git a/dotdrop/installer.py b/dotdrop/installer.py
index 0b05737..d95d8e2 100644
--- a/dotdrop/installer.py
+++ b/dotdrop/installer.py
@@ -219,7 +219,8 @@ class Installer:
             if ret:
                 if self.debug:
                     self.log.dbg('diffing {} and {}'.format(tmpdst, dst))
-                diff = utils.diff(tmpdst, dst, raw=False, opts=opts)
+                diff = utils.diff(tmpdst, dst, raw=False,
+                                  opts=opts, debug=self.debug)
                 if diff == '':
                     retval = True, ''
                 else:
diff --git a/dotdrop/utils.py b/dotdrop/utils.py
index 0038626..807d8ef 100644
--- a/dotdrop/utils.py
+++ b/dotdrop/utils.py
@@ -29,10 +29,10 @@ def run(cmd, raw=True, debug=False):
     return ''.join(lines)
 
 
-def diff(src, dst, raw=True, opts=''):
+def diff(src, dst, raw=True, opts='', debug=False):
     """call unix diff to compare two files"""
     cmd = 'diff -r {} \"{}\" \"{}\"'.format(opts, src, dst)
-    return run(shlex.split(cmd), raw=raw)
+    return run(shlex.split(cmd), raw=raw, debug=debug)
 
 
 def get_tmpdir():