tmux no server running on /tmp/tmux-*/default - Windows msys2 terminal

Question

I'm new to tmux and have been trying to get a .tmux.conf that suits me and build a script to setup a session. At some point I started getting this error

no server running on /tmp/tmux-1065767/default

This message only appears when there is no active session and I run a command like tmux ls.

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I have tried to follow solutions like this one but I am on a Windows 8 machine and the *nix commands aren't working and I have failed to find equivalents. The relevant section from that link being to get the PID with ps and use kill -SIGUSR1 to start a server running on /tmp/tmux-*/default:

% ps aux | grep -w [t]mux
root     14799  0.2  0.0  36020   488 ?        Ss   May08  51:30 tmux
% kill -USR1 14799
% tmux ls
<list of tmux sessions>

If you know equivalent commands to the above for Windows 8, in a msys2 or Git Bash terminal, I would be very grateful.

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In case my .tmux.conf or setup script are an issue I have included them below.

Config file:

# allow names to stick
set-option -g allow-rename off

# use the lovely fish
set-option -g default-shell /usr/bin/fish
set -g default-command /usr/bin/fish

# modify the status bar
set -g status-bg colour233
set -g status-fg colour40
set-option -g status-position top

# new prefix
unbind C-b
set-option -g prefix C-Space

# don't punish slow release of control when moving windows
bind C-n next-window
bind C-p previous-window

# alt close windows
bind X confirm kill-window

# split panes using v and s
bind v split-window -h
bind s split-window -v
unbind '"'
unbind %

# reload config file
bind r source-file ~/.tmux.conf

# hopefully help tmux believe in colourful vim
set -g default-terminal "xterm-256color"

# switch panes using Alt-arrow without prefix
bind -n M-Left select-pane -L
bind -n M-Right select-pane -R
bind -n M-Up select-pane -U
bind -n M-Down select-pane -D

# clear pane title
bind ] select-pane -T ''

Setup script:

#! /bin/bash
# For setting up BrokenFlows' default tmux work space

# for checking if the session exists
desired="dfws"
existing=`tmux ls | grep -o $desired`

if [ "$existing" == "$desired" ] # don't wind up if it's already there
then
    tmux attach-session -t $desired
else
    # if it wasn't there then setup as below

    tmux new-session -s $desired -d # name "DeFault WorkSpace" and detach
# called from cli but affecting most recent session:
    tmux rename-window "home" 

    # split window 0
    tmux split-window -v -p 38 # set bottom to 38% height
    tmux split-window -h -p 60 # set right to 60% width
    tmux split-window -h -p 51 # set right to 51% width

    # setup commands in window 0
    tmux clock-mode -t 0.1 # time in the bottom left pane
    tmux send-keys -t 0.2 'cpu' Enter # % cpu in bottom middle pane
    tmux send-keys -t 0.3 'mem' Enter # MByte mem in bottom right pane

    # open to-do list in window 1
    tmux new-window -n "vim" 
    tmux send-keys -t "vim" 'vim ~/Desktop/Today.taskpaper' Enter

    # go to home window and pane
    tmux select-window -t 0
    tmux select-pane -t 0

    # name panes in window 0
    sleep 2
    tmux set pane-border-status top
    tmux set pane-border-format "#T"
    tmux select-pane -t 0 -T ""
    tmux select-pane -t 0 -T ''
    tmux select-pane -t 1 -T 'Time'
    tmux select-pane -t 2 -T '% CPU'
    tmux select-pane -t 3 -T 'MByte Memory'

    # attach to session now it is set up
    tmux attach-session -d
fi

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I would like to be able to get back to the default behavior where the "no server running" output is replaced by a proper response to commands such as tmux ls.

I expect this requires equivalent commands to ps and kill -SIGUSR1 [PID] on Windows 8, in a msys2 or Git Bash terminal.

Solution

Sending SIGUSR1 to tmux is only useful if the tmux server is already running but something has deleted its socket from /tmp. Are you sure this is the case?

If there is no tmux server running, you just need to start a new one with "tmux new".

Comments

[BitFlow]

I get the error message when there are no sessions running yet and I try something like tmux ls but previously I would have seen a standard output that there were no sessions.

[Nicholas Marriott]

No you will get this message from "tmux ls" when the tmux server is not running and have done since forever. Are you thinking of "tmux attach"? It will respond "no sessions" if the server is not running (because it tries to start the server in case you create sessions in .tmux.conf).

[BitFlow]

Apologies for conflating the two then. You are correct that I misremembered the output of tmux attach as belonging to tmux ls. Thank you for clearing this up for me.