1 + hg init

     2 Is there an error message when trying to diff non-existing files?

     3 + hg diff not found

     4 not: No such file or directory

     5 found: No such file or directory

     6 Is there an error message when trying to add non-existing files?

     7 + hg add not found

     8 not: No such file or directory

     9 found: No such file or directory