vi/vim is a good tool to edit the files for sys admin and programmer.
I don’t mean to offend the emacs guys. just my opinion. 
if you want to learn and have any questions, just use this link.
so you don’t need to search on the internet.
http://vimdoc.sourceforge.net/
the pdf is good book for the new learner.
http://www.truth.sk/vim/vimbook-OPL.pdf