tmux shell for macOS Terminal application

tmux-shell

#!/bin/bash -l
# tmux shell for macOS Terminal application
#
# Starts tmux taking current directory and open tmux sessions into account
#
# When Terminal starts, it's $PWD always equals $HOME. Except cases when Terminal application was told to open
# some particular directory (`open ~/Code -a Terminal` for instance).
#
# In the first case we want to attach to existing tmux session if one exists. If there is more than one
# session open, the script will ask user which session to attach to.
#
# In the case of opening Terminal with some particular directory, new session is created.
#
# https://gist.github.com/astyagun/2c326e9b12e36f25e7ee01c7ccaa4656

function tmux_sessions_count() {
  tmux list-sessions 2>/dev/null | wc -l | tr -d '[:space:]'
}

function request_session_number_from_user() {
  echo There are several sessions open at the moment:
  tmux list-sessions
  echo n: new-session
  echo 'Please enter the number of session to attach to or "n" for a new session: '
  read -n1 SESSION
}

function get_session_number() {
  request_session_number_from_user
  while [ ! $((tmux list-sessions | cut -d: -f1; echo n) | grep $SESSION) ]; do
    print_error_message
    echo
    request_session_number_from_user
  done
  clear
}

function print_error_message() {
  RED="\e[91m"
  BOLD="\e[1m"
  NORMAL="\e[0m"
  RESET="\e[m"
  printf "\n${RED}${BOLD}Error${NORMAL}${RED}: there's no session with number \"${SESSION}\"!${RESET}"
}

if [ $PWD = $HOME ]; then
  TMUX_SESSIONS_COUNT=`tmux_sessions_count`

  if [ $TMUX_SESSIONS_COUNT -gt 0 ]; then
    get_session_number

    if [ $SESSION = 'n' ]; then
      tmux new-session
    else
      tmux attach-session -t $SESSION
    fi
  else
    tmux new-session
  fi
else
  tmux new-session -c "$PWD"
fi