> Eh? test -a isn't POSIX? Is it SuSv3? No, POSIX (IEEE Std 1003.1-2001) == SUSv3. Neither the -a unary operator, the -o unary operator, the -a binary operator, nor the -o binary operator are guaranteed to work with a POSIX-conformant implementation of test, though many will handle 2-4 of these.