diff --git a/iocAdmin/Db/Makefile b/iocAdmin/Db/Makefile
index 4008c63..0b177e2 100644
--- a/iocAdmin/Db/Makefile
+++ b/iocAdmin/Db/Makefile
@@ -48,9 +48,5 @@ $(COMMON_DIR)/iocAdminVxWorks.db: $(COMMON_DIR)/iocAdminScanMon.db $(COMMON_DIR)
 
 $(COMMON_DIR)/siteEnvVars.substitutions: $(EPICS_BASE)/configure/CONFIG_SITE_ENV $(EPICS_BASE)/configure/CONFIG_ENV
 	@echo Expanding siteEnvVars.substitutions from $^....
-	@echo file iocEnvVar.template > $@
-	@echo { >> $@
-	@echo pattern >> $@
-	@echo { ENVNAME, ENVVAR, ENVTYPE } >> $@
-	@sed -n "s/^EPICS_\([A-Z_]*\).*/{\1, EPICS_\1, epics}/p" $^ >> $@
-	@echo } >> $@
+	@$(RM) $@
+	@$(PERL) ../genSiteEnvVars.pl $^ > $@
diff --git a/iocAdmin/Db/genSiteEnvVars.pl b/iocAdmin/Db/genSiteEnvVars.pl
new file mode 100644
index 0000000..2f3406c
--- /dev/null
+++ b/iocAdmin/Db/genSiteEnvVars.pl
@@ -0,0 +1,26 @@
+#!/usr/bin/env perl
+#
+# Usage:  genSiteEnvVars.pl CONFIG_SITE_ENV [ ... ]
+#
+# Reads an EPICS CONFIG_SITE_ENV file and outputs
+# a substitutions file to generate appropriate EPICS
+# records for those variables via iocEnvVar.template
+#
+print <<__END__;
+file "iocEnvVar.template" {
+  pattern { ENVNAME, ENVVAR, ENVTYPE }
+__END__
+
+my @epics_vars;
+while(<>) {
+    $m = s/^EPICS_([A-Z_]*).*\n/${1}/;
+    push(@epics_vars, $_) if $m;
+}
+
+my %varcount;
+my @unique_vars = grep { not $varcount{$_}++ } @epics_vars;
+
+foreach (@unique_vars) {
+    print "{ $_, EPICS_$_, epics }\n"
+}
+print("}\n");