Screwed up my 1TB HD iMac27 - I am running OSX 10.11.5 need to rebuild it in Terminal **

Not sure what I did but I need to regain the space on my 1TB HD. I have made a full back up and need to know the step by step commands in TERMINAL to do this. As you can see I have access to only 120GB. I have attached info/ disc Util info

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Since you have made a full backup, I recommend a full wipe and restore.

120GB plus CoreStorage plus "I had 1TB before" sounds like this is a fusion drive that you have disconnected. 

Reboot the machine in recovery mode (Command-R at power-on) and open Disk Utility. Very easy from there to reformat the internal drives either separately or as a fusion drive again. Then either restore the Time Machine backup or install a new OS and then import your data.

Dealing with core storage volumes in the terminal is very fiddley. Step C depends on the output of step B etc. Quick and easy in Disk Utility.