:::::::::::
:: INPUT ::
:::::::::::
The input will be closed with return or enter key. There may be more than one
command at one line, when they are separated between semicolon.

Example:   UNERASE 3-4;r 3-4

Output can be stopped with entry of a empty line. Output of binary files can
not be stopped.
If BBS receive unknown command lines, BBS will close connection (like BYE).