Question: Is it possible to start a session with layout but detached immediately?

[asartalo]

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I have a layout that I would like to have run some servers or persistent tasks in the background but I don't want to attach to to the session immediately but just detached and then at some point later I can attach to it if needed. Kind of like running tmux in detached mode like tmux new -s foo -d.

[thisismygitrepo]

This is a direly missing feature. Please prioritize its implementationas there is no other ways of achieving it.

[bnwa]

Came to Issues looking for exactly this. In my tmux workflow, I have a fish function I call that sets up a session per repo, executing the desired layout for each, all without ever attaching to a session in particular. Rather surprised to find that missing here. I do enjoy the otherwise vast improvement in sanity from tmux however.

[jayeheffernan]

I'd like this too. My use-case is similar to @bnwa 's.

My use-case

With Tmux I use smug to have predefined layouts in YAML config files - one layout per-project. When I boot my computer I have a small init.sh Bash script to start up all my usual projects in separate Tmux sessions:

tmux start-server
smug start logs --detach
smug start proxy --detach
smug start website --detach
smug start default-project --detach

Workaround

For now I have a workaround of scripting my terminal app (wezterm) to process the right key-presses to start and then detach each session in series. My new init.sh:

#! /usr/bin/env bash

function start-session() {
  local session_name="$1"

  # Send Zellij cli to shell
  wezterm cli send-text "zellij --layout $session_name --session $session_name"
  # send Enter key
  wezterm cli send-text --no-paste '^M'
  # Wait a moment so Zellij has time to start
  sleep 2
  # send "detach" keybinding to Zellij
  wezterm cli send-text --no-paste 'Ctrl-t d'
}

function attach-session() {
  local session_name="$1"
  wezterm cli send-text "zellij attach $session_name"
  wezterm cli send-text --no-paste '^M'
}

start-session logs
start-session proxy
start-session website
start-session default-project

attach-session default-project

Then run it with ./init.sh & (note the & to run in background).

NB: the ^M should not be a carat character followed by an M - it's a literal newline character (typed with Ctrl-v Enter in Vim). Similarl story with Ctrl-t d, which is my configured key-binding for detaching from Zellij. I've edited them here to look readable, but the real script uses special characters to work properly.

[isti115]

Since #3257 this behavior (or at least something similar) can be achieved by the following commands:

zellij attach --create-background example-session
ZELLIJ_SESSION_NAME=example-session zellij action new-tab --layout example-layout.kdl

This still leaves an extra empty tab open, which could be closed by something like:

ZELLIJ_SESSION_NAME=example-session zellij action go-to-previous-tab
ZELLIJ_SESSION_NAME=example-session zellij action close-tab

Ideally the first command would also allow you to specify the desired layout. I'll try to take a look into this to see if I can submit a PR to add that functionality.

---

P.S.: Another possible workaround would be temporarily overriding the default layout before launching the background session.

[imsnif]

Ideally the first command would also allow you to specify the desired layout. I'll try to take a look into this to see if I can submit a PR to add that functionality.

I came here to say that you could do zellij attach --create-background my-session-name options --default-layout <layout> but then found that this isn't working. This is a bug - I'll try to add it to the fixes for the next patch version.

[imsnif]

I came here to say that you could do zellij attach --create-background my-session-name options --default-layout <layout> but then found that this isn't working. This is a bug - I'll try to add it to the fixes for the next patch version.

Fixed in https://github.com/zellij-org/zellij/pull/3288 I want to get a few more small fixes in and will then release a patch. Likely a matter of days.