If you are a developer, you will re-use code provided by others. Usually /lib, /lib64, /usr/local/lib, and other directories stores various shared libraries. You can write your own program using these shared libraries. As a sys admin you need to manage and install these shared libraries. Use the following commands for shared libraries management, security, and debugging problems.
There is a program called trickle. It is a portable lightweight userspace bandwidth shaper. It can run in collaborative mode (together with trickled) or in stand alone mode.