[run_test.bash: show differences
Helmut Grohne <grohne@cs.uni-bonn.de>**20150113141143
 Ignore-this: 7aa3f4b56af33ce358babf4839b18bba
] hunk ./run_test.bash 17
-    | diff -q "$expected_output_fn" - > /dev/null
+    | diff "$expected_output_fn" -