Grab some text and "send" it to a GNU Screen / tmux session.

VIM ---(text)---> screen / tmux

Presumably, your screen contains something interesting like, say, a Clojure REPL. But if it can receive typed text, it can receive it from vim-slime.

The reason you're doing this? Because you want the benefits of a REPL and the benefits of using Vim (familiar environment, syntax highlighting, persistence ...).

Read the blog post.

I recommend installing pathogen.vim, and then simply copy and paste:

cd ~/.vim/bundle
git clone git://github.com/jpalardy/vim-slime.git

If you like it the hard way, copy plugin/slime.vim from this repo into ~/.vim/plugin.

By default, GNU Screen is assumed. It is equivalent to:

let g:slime_target = "screen"

If you would rather use tmux, use:

let g:slime_target = "tmux"

By default, the current paragraph will be sent. This is equivalent to typing vip. If you (visually) select text, that will be sent over:

C-c, C-c  --- the same as slime

There will be a few questions, as to where you want to send your text, and the answers will be remembered. If you need to reconfigure:

C-c, v    --- mnemonic: "variables"