2.6.10. Basic FTP commands

• ABOR - stop file transfer.
• CWD - change the current (active) directory.
• DELE - delete a file.
• LIST - display a list of server files.
• MDTM - display the file modification time.
• MKD - create a directory.
• NLST - display a list of directory files (more concise than LIST). The list is transmitted over the data connection (port 21).
• PASS - pass the password.
• PASV - switch to passive mode.
• PORT - enter the active mode and specify the ports that will be used for data transmission.
• PWD - display the active directory.
• QUIT - disconnect, terminate the connection.
• RETR - Download file.
• RMD - delete a folder on the server.
• RNFR and RNTO - rename the file. Used as: RNFR initial_renamed RNTO file_file.
• SIZE - return the file size.
• STOR - upload the file to the server.
• TYPE - set the file transfer type (binary, ASCII (text)).
• USER - send username.
• APPE - add to a file on the server.
• CDUP - go to the parent directory. Similar to the team cd ..
• HELP - displaying text information of help on working with the server.
• NOOP - do nothing (dummy command).
• STAT - display the current status of the connection with the server.
• STOU - upload unique files to the server. In this case, files with similar names are not transferred.
• STRU - establish the file transfer structure.
• SYST - display information about the system (server).
• PBSZ - set the size of the protected buffer.
• OPTS - a command that calls another optional command with a pre-specified parameter. More details in RFC.
• AUTH - start authorization and encryption operation.

Response code FTP is indicated by the last number in the log and consists of three digits. Each digit indicates a specific state of the command, which can help in reading the response.

1. First digit:
   • 1 – the command is accepted for execution, but not yet completed;
   • 2 – command execution completed successfully;
   • 3 – command accepted and any additional command expected;
   • 4 – the command cannot be executed at the moment;
   • 5 – impossibility of executing a given command;
2. Second digit:
   • 0 – syntax error;
   • 1 – Announcement;
   • 2 – the message refers to either the control connection or the data connection;
   • 3 – a message about user authentication and his rights;
   • 4 – not used\undefined;
   • 5 – file system status message;
3. The third digit finally determines the state of the command.