Arkku's tmux wrapper script

tmx

#!/bin/sh
# A wrapper for running tmux. Takes on (optional) main session name as
# argument, creates it if it doesn't exist. Then (in either case),
# a new slave session is created and attached to the main session.
# The slave session is configured to be destroyed automatically when
# detached, but the main session stays alive. This arrangement allows
# each slave session to have independent control over active windows/panes.
#
# (Make sure ~/.tmux.conf does not interfere by having something like
#  `new-session` or `attach-session` in it.)
#
# By Kimmo Kulovesi <http://arkku.com/> 2017-02-03.
# Distribute freely, use at your own risk only.

if [ -n "$TMUX" ]; then
    echo 'Error: Already in tmux!' >&2
    exit 1
fi

if [ -z "$1" ]; then
    main_session=0
elif [ "$1" = "ls" ]; then
    exec tmux ls
else
    main_session="$1"
fi

if ! tmux ls 2>/dev/null | grep -q "^$main_session:"; then
    echo "New session: $main_session" >&2
    tmux new-session -d -s "$main_session" || exit 1
fi

if [ -z "$2" ]; then
    slave_session="${main_session}_$$"
else
    slave_session="${main_session}_$2"
    if tmux ls 2>/dev/null | grep -q "^$slave_session:"; then
        slave_session="${slave_session}_$$"
    fi
fi

echo "Attaching to $main_session as $slave_session" >&2
exec tmux   new-session -d -t "$main_session" -s "$slave_session" \; \
            set-option destroy-unattached \; \
            attach-session -t "$slave_session"

There is an updated version at https://github.com/arkku/dotfiles/blob/master/bin/tmx