diff --git a/App/tools/expandDBD.pl b/App/tools/expandDBD.pl
index 08f6961..d95df85 100755
--- a/App/tools/expandDBD.pl
+++ b/App/tools/expandDBD.pl
@@ -10,23 +10,24 @@ use File::Spec::Functions qw/catfile/;
 my $epicsversion = 3.14;
 my $quiet = 0;
 my @searchpath = ();
-my @filesDone = ();
+my %filesDone = ();
 my @filesInput = ();
 
 while (@ARGV) {
     my $arg = shift @ARGV;
-    if ($arg =~ /^-(\d*(\.\d*)?)$/) { $epicsversion = $1; }
+    if ($arg =~ /^-\d/) { $epicsversion = substr($arg, 1); }
     elsif ($arg eq "-q") { $quiet = 1; }
     elsif ($arg =~ /^-I$/) { push @searchpath, shift @ARGV; }
     elsif ($arg =~ /^-I(.*)$/) { push @searchpath, $1; }
     else { push @filesInput, $arg; }
 }
+
 ##
 ## Search given dbd file from @searchpath list.
 ## If it is not found, return the file name as it is.
 ## 
 sub finddbd {
-    my $name = $_[0];
+    my $name = shift;
 
     foreach my $dir (@searchpath) {
         my $fullname = catfile($dir, $name);
@@ -43,50 +44,62 @@ sub finddbd {
 ## File after "include" directive is read in too.
 ## 
 sub scanfile {
-    my $fname = $_[0];
-    my $name = basename($fname);
+    my $name = shift; # dbd file to read
+    my $includer = shift; # dbd file and lineno where this dbd file is included.
+    my $lineno = shift;   # they are undef for files from command line.
 
-    if (grep $name eq $_, @filesDone) {
+    my $base = basename($name);
+
+    if (exists($filesDone{$base})) {
         if (!$quiet) {
-            say STDERR "Info: skipping duplicate file \"$name\" from command line";
-        }
-        return;
-    }
-
-    if ($name ne "dbCommon.dbd") {
-        push @filesDone, $name;
-    }
-
-    if (!(open FILE, "<", finddbd($name))) {
-        say STDERR "Error openning file \"$name\" for reading: $!";
-        return;
-    }
-
-    foreach my $line (<FILE>) {
-        if ($line =~ /^[ \t]*(#|%|$)/) {
-            # skip
-        }
-        elsif ($line =~ /include[ \t]+"?([^"]*)"?/) {
-            scanfile($1);
-        }
-        elsif ($line =~ /(registrar|variable|function)[ \t]*\([ \t]*"?([a-zA-Z0-9_]+)"?[ \t]*\)/) {
-            if ($epicsversion > 3.13) {
-                say "$1($2)";
+            if ($includer) {
+                say STDERR "Info: skipping duplicate file $name included from $includer line $lineno";
+            }
+            else {
+                say STDERR "Info: skipping duplicate file $name from command line";
             }
         }
-        elsif ($line =~ /variable[ \t]*\([ \t]*"?([a-zA-Z0-9_]+)"?[ \t]*,[ \t]*"?([a-zA-Z0-9_]+)"?[ \t]*\)/) {
-            if ($epicsversion > 3.13) {
-                say "variable($1,$2)"
-            }
+        return 1;
+    }
+
+    if ($base ne "dbCommon.dbd") {
+        $filesDone{$base} = 1;
+    }
+
+    my $fh;
+    if (!(open $fh, "<", finddbd($name))) {
+        if ($includer) {
+            say STDERR "ERROR: file $name not found in path \"@searchpath\" called from $includer line $lineno";
         }
         else {
-            print $line;
+            say STDERR "ERROR: file $name not found in path \"@searchpath\"";
+        }
+        return 0;
+    }
+
+    foreach (my $n=1;<$fh>;$n++) {
+        chomp;
+
+        if (/^[ \t]*(#|%|$)/) {
+            # skip
+        }
+        elsif (/include[ \t]+"?([^"]*)"?/) {
+            return 0 unless scanfile($1, $name, $n);
+        }
+        elsif (/(registrar|variable|function)[ \t]*\([ \t]*"?([a-zA-Z0-9_]+)"?[ \t]*\)/) {
+            say "$1($2)" if $epicsversion gt 3.13;
+        }
+        elsif (/variable[ \t]*\([ \t]*"?([a-zA-Z0-9_]+)"?[ \t]*,[ \t]*"?([a-zA-Z0-9_]+)"?[ \t]*\)/) {
+            say "variable($1,$2)" if $epicsversion gt 3.13;
+        }
+        else {
+            say;
         }
     }
 
-    close FILE;
+    return 1;
 }
 
-foreach my $fname (@filesInput) {
-    scanfile $fname;
+foreach my $name (@filesInput) {
+    exit 1 unless scanfile($name);
 }