Hello all, I'd tried to use example from Marc Greis' Tutorial to learn creating output files for xgraph. This is the example : (http://www-mash.cs.berkeley.edu/ns/tutorial/examples/example4.tcl) But, after I run this script, xgraph doesn't show up, and there is xgraph.core file at current directory. Please give me some information about this problem. Thanks. Regards, Faisal Adnan