I submitted this question a few days back and got some responses, but I'm still getting what I need. If I have $command below, I need to swap all ${XYZ}'s in the string w/ their corresponding value in $dynamic_vars{xyz}. I broke this up into two steps, because I first need to make all XYZ's lowercase and then secondly swap ${XYZ} for $dynamic_variables{xyz}.
$command = 'Do this ${command} to ${computer}'; $command =~ s[ \$ { ([^}]+) } ] [ $ { \l$1 } ]; $command =~ [same as above][$dynamic_vars{$1}];