music_session_toggle.sh

#!/usr/bin/env bash
# ------------------------------------------------------------------------------
# Description
# -----------
#
#  Little script to jump between any tmux session and an always running one,
#  received as an argument, ie: if you had a session 'main' and you always kept
#  a named window 'Music', you could easily jump to it by calling this scipt
#  like so:
#       $ music_session_toggle "main:Music"
#  Or even have a tmux binding for it like this one (in your ~/.tmux.conf):
#       $ bind m run 'music_session_toggle main:Music'
#
# ------------------------------------------------------------------------------
# Author
# -------
#
#  * Farfanoide (https://github.com/farfanoide)
#
# ------------------------------------------------------------------------------
set -e

_get_prev_session()   { tmux show-environment -g previous_session | cut -d'=' -f2 ;}

_get_current_session(){ tmux display-message -p '#S' ;}

jump_session=$1; shift

if [ -n "${TMUX}" ]; then
  current_session=$(_get_current_session)

  if [[ ! "${jump_session}" =~ "${current_session}" ]]; then
    tmux set-environment -g previous_session $(_get_current_session)
    tmux switch-client -t $jump_session
  else
    previous_session=$(_get_prev_session)
    tmux set-environment -g -u previous_session
    tmux switch-client -t $previous_session
  fi

else
  tmux has-session -t main 2> /dev/null && tmux attach-session -t main:Music
fi