I do most of my work in vim running in a tmux session over ssh. This workflow has been working great for me so far and will probably be the object of a future post.

One thing that gave me a lot of trouble though is how to handle copy/paste across these remote tmux sessions.

A clipboard issue

Let me explain the problem. Let’s say I have to do some work on a remote machine, I connect to it with ssh, attach or start a new tmux session and start vim to begin editing some code or some configuration file.

Now, what if I have some code or a piece of configuration I need to copy from my local browser for example to this remote vim, behind tmux and ssh? How would I do that?

Primary selection

The most straightforward solution would be to reach out for the mouse, select the text to be copied in the browser, return to vim, switch in INSERT mode and paste the text with the middle button.

This solution is using the primary selection clipboard.

Clipboard selection

But I don’t like the mouse, can we do it with the keyboard only ?

Most terminal emulators support paste command with CTRL-SHIFT-V (I personally use alacritty). OK fine that works. Let’s copy the text from the browser using CTRL-C and switch back to vim, go into INSERT mode and paste with CTRL-SHIFT-V.

This would also work from a local vim to a remote one. Copy some text into the + register and paste it with CTRL-SHIFT-V.

This solution uses the clipboard selection.

Copy in remote, paste elsewhere

Now, let’s say I am working in vim in a remote machine, I want to copy some text from my current vim session to a vim running on another machine. Since I am already in vim and probably doing some heavy copy/paste with vim registers already, I really don’t want to grab the mouse for this. It would be really too awkward.

Let’s paste the text in the + register, will I been able to use it from the local OS?

No, that + register is bound to the system on which vim currently runs which is in this case the remote machine.

Enter OSC 52

This is the problem solved by the plugin vim-oscyank. This plugin uses a special OSC sequence that allows to copy some text to the system clipboard from pretty much anywhere as long as it runs into a terminal emulator! The only requirement is that the terminal emulator used must support this sequence. Check out the list of terminal emulators implementing this feature on github.

That means that when you copy some text from vim using this plugin, that text ends up in the clipboard selection of the local OS no matter what. And then you can paste it into any terminal with CTRL-SHIFT-V or for a local vim, using the + register as you would do with a local copy command.

Keyboard only workflow, at last!

Configuration

Among the different configuration options described on the project page, the one I like the most is:

autocmd TextYankPost * if v:event.operator is 'y' && v:event.regname is '+' | OSCYankReg + | endif

With this autocmd in .vimrc, copying some text into the + register make the plugin copy the content to the local OS clipboard using the OSC 52 sequence.

Summary

As a summary, the table below shows the different ways to copy/paste texts between remote and distant machines. On the last line, what the plugin vim-oscyank makes possible.

This plugin makes it possible to copy/paste seamlessly between vim instance across different hosts with the keyboard only. That’s awesome! If you know better way to do it please let me know.