Interestingly, the ksh docco say that 'Conditional Expressions' applies to [[ only :-) and then say the -a is obsolete.
test expression
later says
the -a and -o binary oper-
ators can be used, but they are fraught with pitfalls due
to
grammatical ambiguities and therefore deprecated in favor of
in-
voking separate test commands
Ok let's forget about this...
