or download this
if ( ! -f $BASEDIR/nbssoammsg/tdt/src/tdt9999.cxx ) {
system ( qq(cd $BASEDIR/nbssoammsg/tdt/src));
...
print "Skipping tdtgen file generation -- if you want to force a r
+egen\n";
print "of tdt files, delete $BASEDIR/nbssoammsg/tdt/src/tdt9999.cx
+x\n";
}