script for tmux sessions; placed in /usr/local/bin and marked as executable

tm

#!/bin/sh
export PATH=$PATH:/usr/local/bin

# abort if we're already inside a TMUX session
[ "$TMUX" == "" ] || exit 0

# present menu for user to choose which workspace to open
PS3="Please choose your session: "
options=($(tmux list-sessions -F "#S") "New Session" $(basename "$SHELL" | tr '[:lower:]' '[:upper:]'))
echo "Available sessions"
echo "------------------"
echo " "
select opt in "${options[@]}"
do
    case $opt in
        "New Session")
            read -p "Enter new session name: " SESSION_NAME
            tmux new -s "$SESSION_NAME"
            break
            ;;
                                        $(basename "$SHELL" | tr '[:lower:]' '[:upper:]'))
                                                $(basename "$SHELL") --login
            break;;
        *)
            tmux attach-session -t $opt
            break
            ;;
    esac
done