OTCL for Ns2 Lecture 1

Create two nodes 
program:
     open any text editor and write below program 

set ns [new simulator]  #create a simulator obj [ see tcl first lect]
set nf [open out.name w ]  #open file out.nam assign nf to it . if file is not present it will create it.
$ns nametrace-all $nf #write all simulation data to this file.
           
proc  finish {} {
global ns nf
$ns flush-trace
close $nf
exec nam out.nam & 
exit 0
}
set n0 [ $ns new node]
set n1 [ $ns new node]
$ns duplex-link $n0 $n1 1Mb 10ms DropTail  #transfer rate 1Mb and delay 10ms
$ns at 5.0 "finish"
$ns run 

Now open terminal and go to place where u have saved the file and  write ns example.tcl 
out put: