diff --git a/test/script/regression.py b/test/script/regression.py
index 7b5fe96727..3051e21694 100755
--- a/test/script/regression.py
+++ b/test/script/regression.py
@@ -845,7 +845,7 @@ class TestResultsDiffer(object):
             diff_path = os.path.splitext(os.path.basename(output_file))[0]
             diff_path += "-Diff.txt"
             diff_file = codecs.open(diff_path, "wb", "utf_8")
-            dffcmdlst = ["diff", "--side-by-side", output_file, gold_file]
+            dffcmdlst = ["diff --side-by-side", output_file, gold_file]
             subprocess.call(dffcmdlst, stdout = diff_file)
             Errors.add_errors_out(diff_path)
             return False
diff --git a/test/script/tskdbdiff.py b/test/script/tskdbdiff.py
index a1bcac3187..5f5c7f20f5 100755
--- a/test/script/tskdbdiff.py
+++ b/test/script/tskdbdiff.py
@@ -139,7 +139,7 @@ class TskDbDiff(object):
 
         # If they are different, invoke 'diff'
         diff_file = codecs.open(diff_path, "wb", "utf_8")
-        dffcmdlst = ["diff", "--side-by-side", gold_file, output_file]
+        dffcmdlst = ["diff --side-by-side", gold_file, output_file]
         subprocess.call(dffcmdlst, stdout = diff_file)
         return False