linux mint wifi connection trough terminal

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http://www.linuxquestions.org – hey,, I have dell inspiron n series core i3 processor wit 3 gb ram . Now i m using linux mint 13 but i cant able to install anyting trough terminal. i m using internet trough firefox .wifi is running good. how to do that trough terminal. like i tried trouo install youtube downloder and uses command ,, sudo apt-get -o Acquire::http::proxy172.00.00.00:port //accesing wifi and sudo apt-get install youtube-dl //installing youtube its giving failed to install wifi is working fine . i m using it through browser . please help (HowTos)