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Increased Developer Productivity with Tmux, Part 3: Sessions

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Regards ♨ – Minimul



Understanding Tmux Sessions

In Part 2 I went over my ~/.tmux.conf file. In this installment, I take a peek at another core Tmux element, sessions. Every time Tmux is launched anew it creates a new session. Under the covers, Tmux has a server component that the sessions attach to, a "Mother ship" as it were. It may be confusing at first to learn that Tmux does not launch in stand-alone fashion like say Vim does but the "client-server" design has its advantages. Let's explore Tmux sessions.

  1. To list of all of my current sessions I type tmux list-sessions
  2. It is common for me to have 9 attached sessions as this figure illustrates. I don't like having much more than that as development machine performance can erode.
    Notice these unnamed sessions that only have numbers naming them.
    This section is at the 0:35 mark in the screencast.
  3. If the tmux command with no arguments is executed a new unnamed session will be created.
  4. Just the tmux command alone will create a new session.
    I then detach, <prefix>-d, the session...
    .. and do another tmux list-sessions. See that a new unamed (22) session has been created. Also, notice that its "attached" status is blank since I detached it.
  5. To reattach that session issue a:
  6.   $ tmux attach -t 22
    This section is at the 1:18 mark.
    Minimul says —

    You want to be mindful of how many Tmux sessions you have open as it may lead to a decrease in performance. You're like "no duh" but sometimes because a new session and Tmux itself being command-line centric (not a GUI app like Photoshop) we let it fly under the radar when trying to troubleshoot a poorly functioning development machine. Moreover, if you can't open new windows or panes in a current working session it is likely that you need to kill a session or two.

  7. Next, I delete or "kill" this session.
  8. <prefix> <colon> kill-session is executed to kill a session from within a session.
    After killing the session and relisting, the "22" session is no longer present.
  9. Let's run through making a named session.
  10. The command for a named session is e.g. tmux new -s <session-name>
    On the bash command line I type the session name within the newly created named session to make sure when I reattach this is the proper session.
    After detaching and relisting, I confirm that the "new-sesh" session has been appointed.
    Reattaching with tmux attach -t new-sesh. There is the "my-sesh" from figure 9.
    Named sessions are at the 2:20 mark.
  11. Finally, if you want to kill and restart the Tmux "server" issue a:
  12.   $ tmux kill-server

That concludes installment 3. Sessions

Understanding sessions is fundamental to wielding the Tmux "sword". In this article and screencast, I reiterate exactly how I use sessions, which will cover the basics. There are more advanced topics that I would have you made aware off, primarily multiple users sharing sessions and running a session within a session.

Next in part 4, I ruminate making Tmux starter templates. While you are waiting for the article check out the screencast that is already baked.

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If you like this article and screencast go to the dedicated page for this series at http://minimul.com/teaches/tmux.