opendir is not open, you cannot write to dirhandle 
my $newname = "reference_".$filename ;
if(not rename $filename, $newname ){
   warn "Error renaming $filename to $newname : $!";
}

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In reply to Re: How to prefix a string to all the files in a directories as well subdirectories by Anonymous Monk
in thread How to prefix a string to all the files in a directories as well subdirectories by perladdict

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