When I login, I connect to a tmux session (either by exec'ing tmux if there is no current session, or exec'ing tmux attach if there is).However this means I don't see the login messages (/etc/issue, /etc/motd, amount of mail etc., the stuff that pam provides). Is there a way to get the messages printed inside the tmux session? (The solution should only rely on POSIX shell syntax i.e. not be bash/zsh/other shell specific) 
Pass login messages to tmux
shell;login;pam