cb

Yet another tool to wrap reads from, and writes to the OS clipboard -- it works from within SSH sessions too!

Backgroud

My life as a developer is a mess: at work I have a laptop with Windows 7 and Cygwin installed; I also have a Vagrant box, running Ubuntu, that I use to do the most of my development work. At home I have a Macbook Air, with Mac OS Sierra.

You can easily imagine how quickly I got tired of having to remember which of the various pbaste, getclip et al. command I should have run depending on which terminal window I had opened.

Wouldn't it be nice if I could read from the OS clipboard, or write to it, using a single command line tool? And wouldn't it awesome if the same tool worked on various operating systems? (at least the ones I use on a daily basis)

enters cb..

Installation

Clone the repo, and run make install:

mkdir -p ~/opt/
cd ~/opt
git clone https://github.com/iamFIREcracker/cb.git
cd cb
PREFIX=~/local/bin make install

Usage

Writing to the OS clipboard is as simple as piping to cb whatever it is that you want to save to the clipboard:

> fortune | cb

Reading from the OS clipboard it's even easier:

> cb
A little suffering is good for the soul.
                -- Kirk, "The Corbomite Maneuver", stardate 1514.0

Advanced usage: remote sessions

Most of the development activities I do at work, I do from a Vagrant box; finding proper Vim and Tmux configurations that play nice with the OS clipboard (especially with remote sessions in the mix) has always been painful, so painful that I decided to ship cb with some painkillers for that.

> cb --listen

This will start a daemon, listening on port 5556 (it's the default, but you can change it by overriding the CB_REMOTE_PORT env variable) for commands to read from or write to the OS clipboard. You might wonder: what's so good about it? Well, you can run it on your host machine (ie. the one with a OS clipboard), change the ssh commands you use to log into your remote dev boxes to do some port forwarding magic:

> ssh -R 5556:localhost:5556 devbox ...

And that's it, running cb from the remote host (well, you will have to get cb installed there too..) will get you the content of the host machine OS clipboard

> cb
A little suffering is good for the soul.
                -- Kirk, "The Corbomite Maneuver", stardate 1514.0

Using ~/.ssh/config for per-host clipboard forwarding

Instead of manually specifying port forwarding every time, you can configure it in your ~/.ssh/config file. cb supports initialization via the LC_CB_REMOTE_PORT environment variable, which SSH typically transfers to the remote host (most SSH daemons are configured to accept LC_* variables by default; if yours doesn't, check the AcceptEnv setting in /etc/ssh/sshd_config).

Here's an example ~/.ssh/config entry:

Host devbox
    HostName devbox.example.com
    RemoteForward 5567 localhost:5556
    SetEnv LC_CB_REMOTE_PORT=5567

With this configuration:

• The local machine runs cb --listen on port 5556
• SSH forwards the remote's port 5557 to the local port 5556
• The remote cb uses port 5557 (via LC_CB_REMOTE_PORT)
• Running cb on the remote automatically connects to the right port

OSC52 support (no daemon required)

If your terminal supports OSC52 escape sequences, you can copy to the clipboard without running a daemon or setting up port forwarding. Just set the CB_OSC52 or LC_CB_OSC52 environment variable:

Host devbox
    HostName devbox.example.com
    SetEnv LC_CB_OSC52=1

Then on the remote:

> echo "hello" | cb   # Copies to your local clipboard via OSC52

This works by sending an escape sequence directly to your terminal, which then updates the clipboard. It works through tmux as well (using DCS passthrough).

Tmux 3.3+: You must enable passthrough in your ~/.tmux.conf:

set -g allow-passthrough on

Note: OSC52 only supports copy operations. Paste still requires the daemon approach or a local clipboard tool.

Terminal compatibility: OSC52 is supported by iTerm2, kitty, alacritty, foot, WezTerm, Windows Terminal, xterm (with allowWindowOps), and others. Some terminals disable it by default -- check your terminal's documentation.

Tmux integration

Add the following to your .tmux.conf:

bind -T copy-mode-vi y      send -X copy-pipe-and-cancel "myreattach-to-user-namespace cb"
bind y run "tmux save-buffer - | myreattach-to-user-namespace cb"

myreattach-to-user-namespace is another wrapper I created to try and make sense of all the different OSes I am dealing with, every day.

Vim integration

Adding the following to your .vimrc will probably do it:

function! g:FuckingCopyTheTextPlease()
    let view = winsaveview()
    let old_z = @z
    normal! gv"zy
    call system('cb', @z)
    let @z = old_z
    call winrestview(view)
endfunction

function! g:FuckingCopyAllTheTextPlease()
    let view = winsaveview()
    let old_z = @z
    normal! ggVG"zy
    call system('cb', @z)
    let @z = old_z
    call winrestview(view)
endfunction

vnoremap <leader>y :<c-u>call g:FuckingCopyTheTextPlease()<cr>
nnoremap <leader>y VV:<c-u>call g:FuckingCopyTheTextPlease()<cr>
nnoremap <leader>Y :<c-u>call g:FuckingCopyAllTheTextPlease()<cr>

nnoremap <leader>p :set paste<CR>:read !cb<CR>:set nopaste<CR><leader>V=
nnoremap <leader>P O<esc>:set paste<CR>:read !cb<CR>:set nopaste<CR>kdd

Borrowed from Steve Losh's awesome vimrc -- thanks for all that!

Host beast.tailscale.internal
    HostName 192.168.1.2
    # HostName 10.202.191.107
    User matteolandi
    IdentityFile ~/.ssh/id_beast
    RemoteForward 6556 localhost:5556
    RemoteForward 6557 localhost:5557
    RemoteForward 6558 localhost:5558
    SendEnv -LANG -LC_ALL
    # Here we abuse the fact that LC_* envs are sent by default
    SetEnv LC_CB_REMOTE_PORT=6556 LC_BR_REMOTE_PORT=6557 LC_MG_REMOTE_PORT=6558