shouldnt

 
if ( join '', sort split(//, $word) eq 
     join '', sort split(//, $to_be_matched ) ) {
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be

if ( join('', sort split(//, $word)) eq join('', sort split(//, $to_be
+_matched)) ) {
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(extra parenthesis added )

After adding the parenthesis , i get "Success" (i.e. "bat" = "tab" based on your example), without them the result is "Failure"