For the latest information about the ns Network Simulator, go to the ns manual ay http://www.isi.edu/nsnam/ns/ or http://www.isi.edu/nsnam/ns/ns-documentation.html .
For examples, go to the downloaded ns package folder at ns-2/tcl/ex. In addition, other tutorials include the Marc Greis’s tutorial and the tutorial by Jae Chung - Mark Claypool.
Ns simulator is based on two languages: C++ as the back-end and the oTcl (object-oriented version of tool command language, tcl) as the front-end. NS is a discrete event simulator, where the advance of time depends on the timing of events, which are maintained by a scheduler.
Some Esssential Commands List:
ns – command to verify the installation of tcl shell script and ns network simulator
ns-version – command to return the ns version
ns-random – command to return a random number, uniformly distributed between [0-(231-1)].
ns-random var – var is used to set the seed to random number generator.