Yes you can supress the screen output, you cand find a well detailed explanation of why they happen in the FAQ's, but suffice it to say for now, that anytime you peform a function you have to catch it with a variable
$rc = USE ...
Both right... and a bit wrong, as you were led astray by the OP.
You are absolutely correct to say that you "suppress" the return values of a function by assigning to a variable.
However USE is a command, not a function and as such it does not return a value (it does set @ERROR). Attempting to assign it to a variable is syntactically incorrect.
If the OP is getting codes on the screen it is from something other than USE.
