We can query whether the attr has min or max value or not, to use "-hnv" or "-hxv" flag of "addAttr" command. e.x.) addAttr -q -hnv (-hxv) nodeName.attr;
If the attr has min or max value, we can also query the real value to use "-min" or "-max" flag of "addAttr" cmd. e.x.)addAttr -q -min (-max) nodeName.attr;
Ah ha. that does it. thanks. For some reason it hadn't occured to me that addAttr would have a -query. I'd always thought of it solely in creation terms.