If you would like to use the terminal for hacking, you should be able to do so by downloading various applications and then running them via the command line.
For instance to perform a port scanning to a computer, you should first make sure that you have a port scanning software installed. One good piece of software to perform port scans, is Nmap. To install nmap, type
sudo apt-get install nmap on the terminal prompt.
After you have downloaded and installed it, to perform a basic port scan type in the terminal prompt
nmap -sS 127.0.0.1. This should perform a SYN Stealth Scan on your computer.
Similarly with other software.
NOTE 1: While it is possible to manually download and use the pieces of software required to complete your task, doing so can be tedious. I suggest downloading and using Backtrack Linux, and Ubuntu based and modified distribution, suited for penetration testing and hacking. By suited, I mean that a clean install of that distribution includes a great load of tools that are ready to be used for hacking purposes.
NOTE 2: While I assume that by hacking you either imply that you want to learn, or perform a penetration test, you have to know that an attempt to hack a computer system that neither belongs to you, nor you are authorised to do so, is illegal, and can lead to great trouble, including, but not limited to going to Jail, and being sued for damages *I, personally, do not endorse or promote illegal activites.*
NOTE 3: *If you are looking for a testbed to test your knowledge, and/or learn more about hacking, consider using a virtual lab.* A virtual lab comprises of several virtual machines running concurrently on the same machine, or the same network, configured for a special purposed. Software to create a virtual lab includes the open source and free VirtualBox and the more advanced one (but still open source) QEMU. By setting a virtual lab, you ensure that all machines belong to you (so you are free to do whatever you like to them), and you are also minimizing possible damage to both your physical computer and others.