连接到串行控制台
usage: fx serial [device-path]
If no device path is given, a list of options will be presented.
If the selected device is not readable by the active user account, it will
first be chmod'd to provide access to the current user.
Exit the session with CTRL+o
In order to have arrow keys work, execute `export TERM=xterm; /boot/bin/sh`
on in the console.