How to avoid sudo prompt when configured with --enable-sudo flag

[Bill Tao]

Hi.

I am setting up an experiment as an ns-3 campaign where I am using the real-time mode to provide an emulated transport network for some real software. 

Because of the real time configuration, I want to run the experiment multiple times to improve statistical significance, and to automate this I try to set up a bash script that calls "./ns3 run" multiple times. 

However, at the moment I can't really automate it because each time I execute "./ns3 run", I am prompted with the password by sudo. Also I have to stay in sudo mode because my campaign works with tap bridges too.

So is there a way to work around this?

Thanks.

Regards,

Bill.

[Gabriel Ferreira]

Yes, there is. 

You can define SUDO_PASSWORD with your password (which sounds bad, but is meant for testing). 

Or configure with enable sudo, to enable the sudo bit on the executable and always run it as a superuser, without having to add any password. 

[Bill Tao]

Thank you, Gabriel.

For clarity, I believe this (Approach 2 in the link) is what you mean with defining a SUDO_PASSWORD environment variable?

Also, I believe your 2nd suggestion is how I attempted it, i.e. configure with the --enable-sudo flag, but I am still prompted with the password at the beginning of every run. Am I missing something? I am still calling "./ns3 run ..." as regular user though, i.e. without sudo.

Thanks

Bill

[Tommaso Pecorella]

Hi,

the best option is to add the command to the sudoers, see for example this tutorial:

https://kifarunix.com/run-only-specific-commands-with-sudo-in-linux/

[Bill Tao]

Thank you, Tommaso.