TCL 2nd class

set ns [new Simulator]
set f [open out.tr w]
set nf [open output.nam w]
$ns namtrace-all $nf
$ns trace-all $f
$ns color 1 Blue
$ns color 2 Red
proc finish { } {
    global ns f
    $ns flush-trace
    close $f
    exec nam output.nam &
    exit 0
    }
set n0 [$ns node]
set n1 [$ns node]
$ns duplex-link $n0 $n1 1mb 10ms DropTail

$ns at 5.0 "finish"
$ns run