ACCT: Provide account information (RFC 959).
This server does not use accounts, so the command is accepted as
superfluous. The argument is validated for non-empty syntax.
ALLO: Reserve storage space (RFC 959).
This server does not require pre-allocation, so the command is accepted
as a no-op. The argument (byte count) is validated for correct syntax.
Optional second argument form: ALLO <bytes> R <record-size>
REIN: Reinitialize session (RFC 959).
Flushes all user/account information and transfer parameters.
Any transfer in progress is allowed to complete.
The control connection remains open for a new USER command.
STAT: Return server status or file/directory info (RFC 959 §4.1.3).
Without arguments: returns general server status (211).
With a pathname: returns a directory listing over the control connection.