tests: Solaris cmp complains about empty files, even with -s When you compare an empty file, such as /dev/null, with a non-empty file, Solaris cmp complains on stderr with "cmp: EOF on /dev/null", even if the -s argument is present. GNU cmp makes the complaint, but silences it with -s. We can change the pdiff utility to simply redirect stderr to /dev/null so that we don't have to worry about this difference in the test files.