I'm trying to integrate ipython and vim through a single tmux session using the popular vim plugin "vim-slime." The problem is that while I can get it to work fine provided that vim is opened in a separate tmux window (or using gvim), if I try to send lines of code to a different pane in the same window, at best I wind up sending it to the vim session I'm currently using.

Really what I want in my setup is vim on the right-hand side of the screen, ipython on the upper-left, and a regular command-line on the bottom left. I don't really want to be opening and managing multiple sessions and windows.

Is there a simple way to do this that I just don't know about because of my relative inexperience?

3 Answers 3


Okay, so I was having exactly the same problem, which is what brought me to this question. I have a split session, vim code on the left and a scheme prompt on the right.

My problem was, I thought the session name was the socket name, but they are two different things. I had named the session '0', for the 0-th window, but in fact, the SOCKET is named 'default' despite the session name I specified.

To get a list of the tmux sockets run: lsof -U | grep "^tmux"
I found that from this answer:

The above was helpful to see the actual names of the sockets.

That is what you put in the first prompt. I was putting '0', which was the name of my session, but it was not working. 'default' is what is needed there despite the fact I had named the session.

Then, at the second prompt, I entered (index-0 window, index-1 pane): :0.1

Voila! Finally! It was working. Brilliant, now side-by-side editing!

  • 1
    This solved it!
    – Ram
    Apr 4, 2016 at 16:49

You need to change the target pane with <c-c>v or :SlimeConfig. The default is :, which is "current window, current pane." See :help slime-tmux.

Instead, navigate to the Tmux pane you want to send the text to (the one with iPython running), and from the shell run echo $TMUX_PANE or tmux run "echo #{pane_id}" to find the correct pane ID.

  • Does not work for me. <C-c>v just brings up VISUAL mode. Plus I believe the $TMUX_PANE is not the information sought. Pressing <C-b>x (command to kill a pane) brings up a confirmation request that includes the n° of the pane. This number differs from $TMUX_PANE and appears to be the correct information to answer the OP's requirement
    – Titou
    May 9, 2017 at 11:07
  1. Launch tmux.
  2. Ctrl-b % to split vertically.
  3. Ctrl-b [left arrow] to move to left hand pane
  4. Ctrl-b " to split left hand pane horizontally. You'll now have 3 command lines.
  5. Ctrl-b [up arrow] to move to upper left hand pane, followed by ipython.
  6. Ctrl-b [right arrow] to move to right hand pane.
  7. Launch vim on your Python code.
  8. Send a line using Ctrl-C Ctrl-C, accept socket name as default, and enter :0.0 to select the IPython pane.

default and 0:0 are the socket name and pane id respectively.

  • 1
    This does not address the issue described in my OP.
    – Ram
    Sep 14, 2015 at 15:29
  • @Ram Yes it did : following the steps that Simon gave, I obtain exactly the configuration the OP asked for.
    – Titou
    May 9, 2017 at 11:01

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