在Cygwin环境下使用NS2遇‘invalid command name "new"’错误的解决求助

Hey there, let's tackle this NS2 issue you're facing in Cygwin! That "invalid command name 'new'" error happens because you're trying to use NS2-specific TCL commands in a plain tclsh session—plain TCL doesn't know about the new command that NS2 adds. Let's fix this with these steps:

1. Understand the Root Cause #

The new command is an extension provided by NS2's TCL libraries. When you run plain tclsh, those libraries aren't loaded, so TCL has no idea what new means. Your guess about the #! path isn't the main issue here, but we'll cover that too.

2. Use the NS2 Interactive Shell Instead of Plain TCLSH #

Instead of typing tclsh to start a session, run the ns command directly in your Cygwin terminal. This launches the NS2-enhanced TCL shell, which already loads all the necessary libraries. Once you're in the ns prompt, type:

set ns [new Simulator]

This should work without errors now.

3. Verify NS2 Installation & Environment Variables #

If running ns doesn't work, double-check your NS2 setup:

• Run which ns in Cygwin. If it returns a path (like /home/your-username/ns-allinone-2.35/ns-2.35/ns), NS2 is installed correctly. If not, you'll need to reinstall NS2 properly for Cygwin.
• Check your environment variables with these commands:

  echo $LD_LIBRARY_PATH
  echo $TCL_LIBRARY
  

  These should include paths to your NS2 installation's lib folder and the TCL library folder that came with NS2 (e.g., /home/your-username/ns-allinone-2.35/tcl8.5.10/library). If they don't, add them to your ~/.bashrc file:

  export LD_LIBRARY_PATH=/home/your-username/ns-allinone-2.35/ns-2.35/lib:$LD_LIBRARY_PATH
  export TCL_LIBRARY=/home/your-username/ns-allinone-2.35/tcl8.5.10/library
  

  Replace the paths with your actual NS2 installation directories, then run source ~/.bashrc to apply the changes.

4. Fix the Shebang Line for TCL Scripts #

If you're writing NS2 scripts (instead of using the interactive shell), the shebang line at the top should point to your system's actual tclsh path. To find it, run:

which tclsh

This will return something like /usr/bin/tclsh. So your script's first line should be:

#!/usr/bin/tclsh

Then save your script (e.g., simulation.tcl) and run it with ns simulation.tcl—this ensures NS2's libraries are loaded when the script runs.

内容的提问来源于stack exchange，提问作者Swamy