I can't install command line on Ubuntu 12.04

I'm running Ubuntu 12.04 LTS and trying to install command line. This is what I get :

micah@micah-laptop:~/Documents$ sudo apt-get install nodejs-legacy
[sudo] password for micah:
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package nodejs-legacy

I'm not a serious linux guy, so I don't know what to do next. Explain to me like I'm a 37 year old math professor.

Start with the reported Ubuntu 12.04 apt-get command and the nodejs-legacy package error. Review the project's command-line installation guidance and determine what a supported installation path should be; done means the instructions address this failure and the command-line client can be installed.

Written by the indexing model from the issue text.