不知道为啥就是不行，不过本来就对 docker 这玩意没啥好感。

$ docker exec -it foo /bin/bash
foo@649fb21d747c:~$ stty size
0 0
foo@649fb21d747c:~$ reset -w
foo@649fb21d747c:~$ stty size
24 80
foo@649fb21d747c:~$ # That was still wrong. Now resize the terminal to get a SIGWINCH.
foo@649fb21d747c:~$ stty size
69 208
foo@649fb21d747c:~$ exit
exit
$ docker exec -it foo /bin/bash # Try it again.
foo@649fb21d747c:~$ stty size
69 208
foo@649fb21d747c:~$ # Doesn't happen anymore for this session.