ns正确安装后，运行simple.tcl是可能出现
nam: Can't finda usable tk.tcl in the following directories:
/home/byf/ns-allinone-2.35/tcl8.5.10/library/tk8.5/home/byf/ns-allinone-2.35/tcl8.5.10/tk8.5 ./lib/tk8.5/home/byf/ns-allinone-2.35/lib/tk8.5 ./library
……
This probablymeans that tk wasn't installed properly
可以尝试将nam的路径加到环境变量中
