Perl in a Nutshell, 2nd Edition

The FTP Protocol

When a server accepts FTP requests, it opens a port (generally port 21) for incoming connections and authenticates clients based on account or anonymous privileges. A user may log in with a legitimate account on that machine, provide her own password, and access any file she normally has access to under the Unix shell. Many servers also allow “anonymous” FTP, in which users log in with the name “anonymous” and use their email address as the password. They are then granted restricted access to a limited portion of the filesystem.

The FTP commands defined in RFC 959 are listed in the following table:

Command	Meaning
ABOR	Abort previous FTP command.
ACCT	Specify the user’s account.
ALLO	Tell server to allocate additional storage for new file.
APPE	Tell server to append to an existing file.
CDUP	Change to parent directory.
CWD	Change directory.
DELE	Delete a file.
HELP	Get help.
LIST	List files for display.
MKD	Make a directory.
MODE	Specify the data transfer mode.
NLST	List files for additional processing.
NOOP	No-op.
PASS	Specify the user’s password.
PASV	Tell server to go into “passive” mode.
PORT	Specify data port for connection.
PWD	Print working directory.
QUIT	Close connection.
REIN	Reinitialize connection.
REST	Restart a file transfer.
RETR	Retrieve a file.
RMD	Remove a directory.
RNFR	Specify pathname of file to be renamed.
RNTO	Specify new name of file being renamed.
SITE	Provide additional site-specific services.
SMNT	Mount a different filesystem.
STAT	Get status.
STOR	Tell server to accept a file for storage.