get_session() {
    local sessions
    sessions=$(tmux ls 2>/dev/null | cut -d: -f1)

    local count
    count=$(echo "$sessions" | wc -l)

    if [ "$count" -eq 0 ]; then
        echo "Error: no tmux sessions found." >&2
        return 1
    elif [ "$count" -gt 1 ]; then
        echo "Error: more than one tmux session found:" >&2
        echo "$sessions" >&2
        return 1
    fi

    export SESSIONNAME="$sessions"
    echo "$SESSIONNAME"
}