--- a/lib/SI/tools.pm	Fri Jan 22 23:28:45 2010 +0100
+++ b/lib/SI/tools.pm	Mon Feb 01 00:07:30 2010 +0100
@@ -8,7 +8,7 @@
 use Data::Dumper;
 use base "Exporter";
 
-our @EXPORT = qw(&run &verbose &find_by_devid &cat &barf);
+our @EXPORT = qw(&run &verbose &find_by_devid &cat &barf &def);
 
 sub run(@) {
     system(@_);
@@ -16,6 +16,10 @@
       if $?;
 }
 
+sub def($$) {
+    return defined $_[1] ? $_[1] : $_[0];
+}
+
 sub barf(@) { die Dumper @_ }
 
 sub cat($) {