For my networking course, we are assigned some labs that require using a Wireshark, a free packet sniffer. These labs have forced me to start learning some basic commands in Terminal. I am currently running Mac OS X 10.11.
To get one's IP address, assuming en1 to be what you want:
ipconfig getifaddr en1
To find your DNS address:
To flush the DNS cache:
sudo killall -HUP mDNSResponder
For my internship, I have been learning Python, particularly v2.7.11, with Learning Python the Hard Way, various online resources, and a couple of books. Usually I do my work in my office on a Windows machine, on which I typically use Spyder and Windows PowerShell—how had nobody ever heard of it?—for Python.
At home, in the past, I have used the text editor BBEdit to write the Python code and IDLE. Now I am trying to copy what I do in the office, which led me to discovering that Mac OS X' Terminal does not have tab-autocompletion enabled by default. A travesty!
Thankfully, MacDaddy.com has very helpful page that explains how to add tab-autocompletion functionality and make Terminal far more useful.