diff --git a/t/compress/CompTestUtils.pm b/t/compress/CompTestUtils.pm
index 9e86005..a2dad90 100644
--- a/t/compress/CompTestUtils.pm
+++ b/t/compress/CompTestUtils.pm
@@ -233,7 +233,7 @@ sub hexDump
         }
         print "   " x (16 - @array)
             if @array < 16 ;
-        $data =~ tr/\0-\37\177-\377/./;
+        $data =~ s/[[:^print:]]/./g;
         print "  $data\n";
     }