Tjyylli

What I Want

I'm trying to automate connecting to a remote machine in multiple, seperate ssh terminals and have independent tmux sessions for each remote terminal while sharing the same windows (i.e. can change session settings and active window/pane without affecting other remote terminals while still having access to the same tmux windows).

I want to do this without changing how the tmux executable is initially run and entirely in a per-user way (all changes limited to /home/$USER/).

How I'm Trying To Accomplish It

Ubuntu 16.04
TMUX 2.1 (from package manager)

I'm using MS's port of ssh (OpenSSH) on my local system (Windows 10).

Currently when I open a remote terminal (or a local terminal for that matter) tmux is launched via /etc/profile.d/ and creates an entirely new session. I have a ~/.tmux.conf file with the following line:

#(this is a single line in my .tmux.conf, I've broken it up here for readability)



if-shell 'tmux has-session -t theonering' 

    'new-session -t theonering'           

    'rename-session theonering'

I'm, also setting destroy-unattached on at the session level in that second line, but I left it out for clarity here. It doesn't change the outcome.

What I Expect To Happen

This states, to the best of my understanding (see Documentation below), that "if, from a shell, tmux says it has a session named theonering then create a new (unnamed) session and group it with theonering. if tmux does not have a session named theonering renamed the current session to theonering."

What Actually Happens

Now if I connect remotely, detach from the existing session, then run the above command (prefixed with tmux, obviously)? Works great.

But if I put it in my ~/.tmux.conf? bupkiss. It's the same as if the line wasn't there at all. No error, no message, no deviation from stock behavior.

Documentation

if-shell from the tmux manpage:

if-shell [-bF] [-t target-pane] shell-command command [command]

Execute the first command if shell-command returns success or the second command otherwise. Before being executed, shell-command is expanded using the rules specified in the FORMATS section, including those relevant to target-pane. With -b, shell-command is run in the background.

If -F is given, shell-command is not executed but considered success if neither empty nor zero (after formats are expanded).

How to determine if the session exists:

has-session [-t target-session]

Report an error and exit with 1 if the specified session does not exist. If it does exist, exit with 0.

How to create a new session that groups with the existing session:

new-session [-AdDEP] [-c start-directory] [-F format] [-n window-name] [-s session-name] [-t target-session] [-x width] [-y height] [shell-command]

Create a new session with name session-name.

The new session is attached to the current terminal unless -d is given. window-name and shell-command are the name of and shell command to execute in the initial window. If -d is used, -x and -y specify the size of the initial window (80 by 24 if not given).

If run from a terminal, any termios(3) special characters are saved and used for new windows in the new session.

The -A flag makes new-session behave like attach-session if session-name already exists; in this case, -D behaves like -d to attach-session.

If -t is given, the new session is grouped with target-session. This means they share the same set of windows - all windows from target-session are linked to the new session and any subsequent new windows or windows being closed are applied to both sessions. The current and previous window and any session options remain independent and either session may be killed without affecting the other. Giving -n or shell-command are invalid if -t is used.

The -P option prints information about the new session after it has been created. By default, it uses the format ‘#{session_name}:’ but a different format may be specified with -F.

If -E is used, update-environment option will not be applied. update-environment.

How to rename the current session:

rename-session [-t target-session] new-name

Rename the session to new-name.

And, of course, I'm assuming if-shell treats exit code 0 as "success" and any other exit code as "otherwise".