diff --git a/utils/csv_dequote.pl b/utils/csv_dequote.pl
index f04a055fec..35cc7c7270 100755
--- a/utils/csv_dequote.pl
+++ b/utils/csv_dequote.pl
@@ -46,8 +46,8 @@
 
 my $csv = Text::CSV->new();
 
-open (CSVin, "<", $infile) or die "$infile: $!";
-open (CSVout, ">", $outfile) or die "$outfile: $!";
+open (my $CSVin, "<", $infile) or die "$infile: $!";
+open (my $CSVout, ">", $outfile) or die "$outfile: $!";
 
 
 while (<CSVin>) {