IInstalling NS2 on Ubuntu 12.04

Step-1: Open the terminal and install the following packages.

sudo apt-get install gcc g++ python             
sudo apt-get install gcc g++ python python-dev
sudo apt-get install mercurial
sudo apt-get install bzr
sudo apt-get install gdb valgrind
sudo apt-get install gsl-bin libgsl0-dev libgsl0ldbl
sudo apt-get install flex bison libfl-dev
sudo apt-get install g++-3.4 gcc-3.4
sudo apt-get install tcpdump
sudo apt-get install sqlite sqlite3 libsqlite3-dev
sudo apt-get install libxml2 libxml2-dev
sudo apt-get install libgtk2.0-0 libgtk2.0-dev
sudo apt-get install vtun lxc
sudo apt-get install uncrustify
sudo apt-get install doxygen graphviz imagemagick 
sudo apt-get install texlive texlive-extra-utils texlive-latex-extra
sudo apt-get install python-sphinx dia
sudo apt-get install python-pygraphviz python-kiwi python-pygoocanvas libgoocanvas-dev
sudo apt-get install libboost-signals-dev libboost-filesystem-dev
sudo apt-get install openmpi*

Step-2: Download the all-in-one tar.gz file from http://www.isi.edu/nsnam/ns/

Step-3: untar it using "tar zxvf ns-allinone-xxx.tar.gz"
Once all files are extracted enter into the directory through the terminal and run "./install". Once installed the terminal will look something like this and will ask you to add some directoties to your PATH environment.

 Step-4: PATH is an enviroment variable. Basically, it tells your machine were to search for programs.
Open a new terminal and edit the following file from your home directory using:
"gedit ~/.profile"
find the following line: PATH="$HOME/bin:$PATH"
and add a colon and paste the given directory.... something like this - PATH="$HOME/bin:$PATH://home/kartheek/Desktop/Cop/ns-allinone-2.35/bin".

Step-5:  Add two more environment variables as shown in the terminal for LD_LIBRARY and TCL_LIBRARY as follows:

export LD_LIBRARY_PATH="/home/kartheek/Desktop/Cop/ns-allinone-2.35/otcl-1.14:/home/kartheek/Desktop/Cop/ns-allinone-2.35/lib"
 
export TCL_LIBRARY_PATH="/home/kartheek/Desktop/Cop/ns-allinone-2.35/tcl8.5.10/library"

Step-6: Now NS2 has been installed and configured.... to validate it do the following:
cd ns-2.35; ./validate (may take a really long time!!!)

One last step....to start using the network simulator install the following:
sudo apt-get install ns2 nam xgraph