Thank you Henrik and Martti, "diff -w jack.cpp.default jack.cpp" does the trick, so it was my fault. When using hexdump I noticed that not the complete file were listed by the diff without -w, I was mistaken. Comparison with hexdump shows that the edited file sometimes is different \n vs \r \n: 0000130 I T = 0 ; 0000140 \n c o n s t i n t S T R E 0000150 A M _ O P E N 0000140 = 0 ; \r 0000150 \n c o n s t i n t S T R E A 0000160 M _ O P E N Regards, Ralf