If you use screen, you can copy from there just like in emacs:
Assume screen prefix key is C-p: (default is C-a)
C-p [ ==> SPC ==> C-f or/and C-n ==> >
Now you have a copy of the text in a file named ~/.screen_exchange
to set it, write in your .screenrc:
,----
| bufferfile $HOME/.screen_exchange
`----
Note: i think the default if you set nothing is /tmp/.screen_exchange
but i am not sure.
Now if you define a little function with a global-key like:
,----
| (defun tv-yank-from-screen ()
| (interactive)
| (insert-file-contents "~/.screen_exchange"))
|
| (global-set-key (kbd "C-c Y") 'tv-yank-from-screen)
`----
you can now yank what you want from your terminal :)