diff --git a/xxdi.pl b/xxdi.pl
index acc974c..4db88a6 100755
--- a/xxdi.pl
+++ b/xxdi.pl
@@ -26,8 +26,7 @@
 # to '_', or, if this is stdin, just use "stdin" as the name.
 if (@ARGV) {
 	$var_name = $ARGV[0];
-	$var_name =~ s/\//_/g;
-	$var_name =~ s/\./_/g;
+	$var_name =~ s/[\.\/\$]/_/g;
 } else {
 	$var_name = "stdin";
 }