I want to debug tcl script in ns, I have add a -DHAVE_LIBTCLDBG on DEFINE line in Makefile, and recomplie the ns, When I run "ns -D 1 xxx.tcl " the ns still can't recognize the build-in debug command, such as "s", "n" "b", it try to look for this command in the PATH. Which line else should I change? Thanks in advance . :-) Tian B.