Use {} to delimit the variable name
$_ =~ s/<CT>/<section id=\"ch${acno}fm\" label=\"\" xreflabel=\"\" rol
+e=\"fm\">/g;
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
Lingua non convalesco, consenesco et abolesco. -- Rule 1 has a caveat! -- Who broke the cabal?
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.