Vim unnamed register + or *

The following will work only if vim --version indicates that you have +xterm_clipboard feature. If not, you will have to install extra packages or recompile vim with that feature added.

There are actually two options for this:

"+y

copies to the "usual" clipboard buffer (so you can paste using Ctrl+V, right click and select "Paste" etc), while

"*y

copies to the X11 selection - you can paste from this buffer using middle click.

Note that "* and "+ work both ways. So if you have selected some text in another application, you can paste it into vim using "*p and if you have copied some text (using, say, Ctrl-C) then you can paste it into vim using "+p.

Vim uses the system cut-and-paste mechanism to copy text between instances. When you run vim in a terminal, it doesn't have direct access to any cut-and-paste mechanism. If vim is running in xterm or some other terminal that provides access to X selections and clipboard contents, vim can use that; however your vim binary is compiled without support for that feature.

If both vim instances are running on the same machine, you can use a temporary file to communicate:

:w ~/vim.tmp
:r ~/vim.tmp

If both vim instances are connected to the same X display (in that the DISPLAY environment variable points to the same X display, the vim programs themselves don't need to have any kind of X support), you can use the X selections via an external program such as xsel or xclip. You can omit the p or -selection primary or choose a different selection (-s/secondary or -b/clipboard). Use :w ! (note the space) to copy:

:w !xsel -ip
:w !xclip -i -selection primary

and :r! to paste:

:r !xsel -op
:r !xclip -o -selection primary