运行ns2

装好ns2后,修改环境变量,但输入ns后,出现以下错误:
The program 'ns' is currently not installed.  You can install it by typing:
sudo apt-get install host
Make sure you have the 'universe' component enabled
bash: ns: command not found

确信ns2已经正确安装,所以可能是.bashrc的问题,网上搜索后得到以下答案:
Your .bashrc wasn't read. Either log-out/log back in, or, simply do a
"source .bashrc" at your prompt.

输入命令: source .bashrc

问题得到解决,终于看到nam窗口了~~