Как написано на справочной странице ssh
:
-t Force pseudo-tty allocation. This can be used to execute arbi-
trary screen-based programs on a remote machine, which can be
very useful, e.g. when implementing menu services. Multiple -t
options force tty allocation, even if ssh has no local tty.
Так что вы должны использовать
ssh -tt user@ip 'ls -la; bash'