Junjue Wang

(王俊珏)

9127 Gates Hillman Center, 4902 Forbes Ave
15213
Pittsburgh
USA

junjuew.github.io

junjuew dot cs dot cmu dot edu
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Mouse-free Copy + Paste on Linux (Ubuntu)

Recently, a friend who is new to Ubuntu, asks me “Why cannot I copy from terminal to GUI application in Linux”? A quick google search finds many similar questions on StackOverflow UbuntuForum. However, none of the solutions given is satisfying. Therefore, I’d like to share my solution in this post.

Intuitively, copy/paste function should consist of simple functionalities of selecting a text region, copying the region, and pasting the region. It should work among any applications a user is using, no matter if the application has a GUI, e.g. a browser, a text terminal, or an editor running in terminal mode.

Sadly, this is not the case on linux. The fundamental reason is that GUI applications are treated differently from non GUI-based applications. Linux GUI applications use X11 library. These applications act as X11 clients connecting to a window display environment (X11 server). The copy/paste behaviors are supported by X11 among GUI applications. Nonetheless, for applications that do not use X11, e.g. emacs -nw (terminal mode), it is not able to use the copy/paste function supported by X11.

If you use Emacs’s built-in M-w to copy your selection, following table demonstrates in which combination the following “paste” would succeed.

Copy To Emacs Emacs -nw (Terminal Mode** Browser
Emacs Y    
Emacs -nw N Y  
Browser Y N Y

So how do we fix this? What is a general solution to copy/paste between GUI applications and terminals?

The solution is Make sure we are only copying among GUI applications.. What?? You might think this is silly and not a solution at all. But hear me out. Unless you are dealing with a console or in a command line tty, you are probably running inside a desktop environment. The terminal application in Ubuntu defaults to gnome-terminal, which is a GUI application. In it, mouse can be used to select the region, Ctrl+Shift+c and Ctrl+Shift+v can be used to copy and paste to/from gnome-terminal.

However, this solution involves using the mouse. And reaching out to a mouse is much slower than using the keyboard. To set a mark without mouse in a terminal, Tmux is here to help. Tmux is a terminal multiplexing tool most famous for its capability to survive abrupt ssh connection drops. It has a rich set of features in managing terminals. To our concern, it has a copy mode, in which one can use to select text inside a terminal with keyboard. Together with tmux-yank plugin, it is able to use X11 clipboard to copy/paste to/from other X11 applications. See my ansible role here and tmux configuration file to customize tmux and install tmux-yank to enable mouse-free copy/paste between terminal and X11 apps. With the customization, to do copy/paste, use: * Enter copy mode: Ctrl-b Enter * Set Mark: v * Copy: y * Exit copy mode: Escape * Paste: Ctrl-b ]