stmux

#!/bin/sh

# tmux shared session wrapper script, by Lucas Ritzdorf (v3.1)
# Manages socket stuff, to make session sharing easier

# To allow session sharing based on a group other than users' primary group,
# ensure that users' shell sessions "export STMUX_GROUP=whatever". Their
# sessions will then be joinable by anyone else in that group.

# Configuration variables
# You can change these!
stmux_dir=/tmp/tmux-shared

# Check arguments
username=$(whoami)
if [ -z "$1" ] ; then
    socket=$username
else
    socket=$1
fi
session=$socket
if [ -n "$2" ] ; then
    echo "Extra arguments detected; ignoring..."
fi

# Create a shared folder for tmux sessions, if it doesn't exist already
if ! [ -d $stmux_dir ] ; then
    mkdir $stmux_dir
    chown "${STMUX_GROUP:-}" $stmux_dir
    chmod g+ws $stmux_dir
fi

# Start tmux using a shared socket
if [ -S $stmux_dir/$socket ] ; then
    # The socket already exists...
    if tmux -S $stmux_dir/$socket has-session -t $session ; then
        # ...and has the desired session...
        if [ $session = $username ] ; then
            # ...and is our session; connect to it
            echo "Existing session found, connecting directly..."
            tmux -S $stmux_dir/$socket attach -t $session
        else
            # ...and is not already our session; link to the existing session with a new one
            echo "Creating new session to track existing target session..."
            tmux -S $stmux_dir/$socket new-session -d -t $session -s $username \; set-option -q -t $username destroy-unattached
        fi
    else
        # ...but does not contain the target session; create it
        echo "Creating new session in existing socket..."
        tmux -S $stmux_dir/$socket new-session -s $session
    fi
else
    # The socket does not yet exist; create it and start a session
    echo "Creating socket..."
    tmux -S $stmux_dir/$socket new-session -s $session
fi

# After tmux exits, check if socket is still in use...
if [ -e $stmux_dir/$socket ] && ! tmux -S $tmux_dir/$socket ls &> /dev/null ; then
    # ...and if not, delete it
    rm $stmux_dir/$socket &> /dev/null
fi