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* by default, warning messages go to stderr * if -A or -a is used, send warning messages to stdout instead. The behaviour in 1.50 meant that somevar=`sysctl -n machdep.booted_kernel 2>/dev/null` could end up with $somevar="machdep.booted_kernel: the value is not available" rather than the more useful $somevar="". (This way, "sysctl -A | grep ..." is still useful.)