To get the equivalent of kill line command in emacs for copying purposes, I use the following code snippet.
Just copy paste it in your .emacs file.

(defun copy-line (arg)    
"Copy lines (as many as prefix argument) in the kill ring"    
(interactive "p")    
(kill-ring-save (line-beginning-position)    
(line-beginning-position (+ 1 arg)))    
(message "%d line%s copied" arg (if (= 1 arg) "" "s")))    
(global-set-key "\\M-k" 'copy-line)    

If \C is your control key then \M is your alt key.
So generally by default your kill line can be done by \C-k
Now you can also copy a line by doing: \M-k I don’t remember where I got this bit of code from, I lost those tabs when Firefox crashed.

So I thought I’d just add it in here for later reference.
Hope it helps