XRPi Documentation - Sysop Commands

FTP Commands

Name

FTP-CMDS -- FTP Server Commands.

Description

XRPi's FTP server accepts the following commands:

ABOR	CDUP	CWD	DELE	HELP	LIST	MDTM	MKD
MODE	NLST	NOOP	PASS	PASV	PORT	PWD	QUIT
REST	RETR	RMD	RNFR	RNTO	STOR	STRU	SYST
TYPE	USER	XMKD	XPWD	XRMD

Commands are case-insensitive, thus "cwd", "CWD" and "cWd" are equally valid.

Arguments are case sensitive. "/TMP" is not the same as "/tmp" or "/Tmp".

Both UNIX style (e.g. /pub/fred) and DOS style (e.g. \pub\fred) pathname conventions are accepted.

The FTP commands are described in detail below:

ABOR -- Abort data connection.

Syntax: ABOR

The ABOR command tells the server to abort any data transfer currently in progress and close the data connection. The control connection is not closed.

If the data connection is not open, this command has no effect.

CDUP -- Change Directory Up By One Level

Syntax: CDUP

The CDUP command changes the current working directory up one level to the parent directory, i.e. it performs the function of "CWD .."

This command has no arguments, and if already at the root it has no effect.

CWD -- Change Working Directory

Syntax: CWD <path>

The CWD command changes the current working directory (and drive if necessary) for the FTP session.

Examples:

	CWD fred         Change to sub-directory "fred".
	CWD ..           Change up one level to parent dir.
	CWD /            Change to root directory
	CWD /FRED/jim    Change to "jim" subdirectory of FRED.

DELE -- Delete file(s).

Syntax: DELE [dir/]<mask>

Examples:

	DELE JIM.TXT         Delete JIM.TXT from current dir.
	DELE /FRED/DOG.EXE   Delete DOG.EXE from dir. /FRED
	DELE *.BAT           Delete files with .BAT extension.

Notes: Wildcards '*' and '?' are accepted.

HELP -- Display help for FTP server commands.

Syntax: HELP [command]

Examples:

	HELP        Displays basic info / cmd list.
	HELP CWD    Gives help for the CWD command.

Some FTP clients may intercept the HELP command to give help on client commands. In this case, the REMOTEHELP command, if it is implemented should translate to a server HELP command. If not, the client may have a command which passes commands "RAW" to the server. If all else fails, TELNET to port 21 and the HELP command will work.

LIST -- lists FTP server directory contents.

Syntax: LIST [dir/][mask]

The LIST command causes a directory listing to be sent from the FTP server to the client over the data connection. If the data connection cannot be established, the command will fail.

The optional argument consists of a directory path and filename mask. If no path is specified, the current directory is assumed. If no mask is specified, "*" (all files) is assumed. Wildcards '*' and '?' are accepted.

Examples:

 LIST              Show all files in current directory
 LIST /PUB       Show all files in PUB subdir of the root
 LIST HTTP/*.htm   Show all ..htm files in HTTP directory.

See also: NLST -- List names only

MDTM -- Retrieve file modification time.

Syntax: MDTM <pathname>

The MDTM command returns the last modification time of the file whose pathname was supplied. Used as an adjunct to the RESTart command, to determine if the file has been modified since the failed transfer.

Example:

	MDTM /home/xrpi/IPROUTE.SYS

The return value is of the form YYYYMMDDHHMMSS, e.g. 20190407134203, representing 13:42:03 on 7th April 2019.

MKD -- Make new directory.

Syntax: MKD <pathname>

The MKD command creates a new directory of the specified name. If pathname is not fully qualified, the new directory is created within the current working directory.

Examples:

	MKD FRED
	MKD /JIM/BILL

See also: RMD -- Remove directory

MODE -- Specifies the data transfer mode.

Syntax: MODE <mode_code>

MODE specifies how the data is to be formatted and transferred via the data connection. Mode codes are as follows:

	B - Block         Data is sent in blocks
	C - Compressed    Data is compressed
	S - Stream        Data sent as stream of characters

The default transfer mode, which is the only one currently implemented, is Stream. The command is included to prevent unnecessary error replies.

Examples:

	MODE S   Sets (S)tream transfer mode.

NLST -- Lists directory contents in short form.

Syntax: NLST [<filespec>]

The NLST (Name List) command causes a directory listing to be sent from the FTP server to the client over the data connection. If the data connection cannot be established, the command will fail.

The optional argument consists of a directory path and filename mask. If no path is specified, the current directory is assumed. If no mask is specified, "*" (all files) is assumed. Wildcards '*' and '?' are accepted.

The listing consists of filenames only, without size, date and other supplementary information.

Examples:

	NLST
	NLST /PUB
	NLST /tmp/*.log

See also: LIST -- List directory contents

NOOP -- (NO OPeration) does nothing.

Syntax: NOOP

The NOOP command does not affect anything, and its only action is to cause the server to send an "OK" reply. It is perhaps useful for testing that the control connection is still functioning, or for keeping it alive.

PASS -- Specifies user password at login.

Syntax: PASS <password>

The argument to the PASS command is either a string of up to 5 characters in response to the secure password challenge or, for use on secure links only, the password itself. The string may not contain spaces.

The command must be immediately preceded by the USER command, which causes the system to reply with a matrix consisting of 5 lines of 5 numbers thus:

	4 1 6 3 7
	3 5 2 6 3
	7 1 9 2 4
	2 7 1 4 6
	3 5 2 6 1

The remote sysop must then choose ONE of the lines, and send the PASS command followed by the 5 characters from the password string which correspond to the 5 numbers on the chosen line. There must be a space after PASS but no spaces between the characters.

Examples:

	PASS RETAW        <-- Matrix response
	PASS squirrels    <-- Raw password

If the sysop has connected on a port which has SYSOP=1 in the config file (e.g. a secure wire link), the response to this command is ignored, and the sysop is granted full access.

See also: USER -- Specify your username.

PASV -- Use "passive" transfer mode.

Syntax: PASV

Normal FTP relies on the server being able to initiate a data connection to TCP port 20 on the client host. This method may however not work if the client is located "behind" a firewall or connection multiplexer.

Passive mode opens a data connection on the server, informs the client of the IP address and port number, and waits for the client to connect to it. It can therefore work via firewalls.

PORT -- Specifies IP address and port for the data connection.

Syntax: PORT h1,h2,h3,h4,p1,p2

The PORT command specifies the IP address and TCP port number to be used by the data connection. The argument is the concatenation of a 32 bit IP address and a 16 bit TCP port number, split into 8 bit fields, each field being transmitted as a decimal number. The fields are separated by commas, and the high order fields are transmitted first.

Example:

	PORT 44,131,91,2,4,1

	Specifies IP address 44.131.91.2 and TCP
	port number 0401 (1001 decimal)

Under normal circumstances this command is not needed. The data connection defaults to TCP port 20 at the client's IP address of the control connection. However, it allows data to be sent to a different host if required.

PWD -- Print Working Directory.

Syntax: PWD

The PWD command causes the full path of the user's current working directory to be displayed via the control connection.

See also: CWD -- Change Working Directory

QUIT -- Terminates an FTP session.

Syntax: QUIT

If a file transfer is not in progress, the QUIT command terminates the FTP session and closes the control connection.

If file transfer is in progress, the control connection will remain open until transfer is complete, allowing the result code to be sent. The control and data connections will then close.

An unexpected close on the control connection will abort any data transfer currently in progress.

See also: ABOR -- Abort current command.

REST -- Restart a failed transfer.

Syntax: REST <offset>

The REST command restarts a file transfer at <offset> bytes from the start of the file. It is usualy followed by a STOR or RETR command.

Example:

	REST 10034	Restart transfer at offset 10034

RETR -- Retrieve (download) file.

Syntax: RETR [path/]<filename>

The RETR command causes the named file to be sent from the FTP server to the client over the data connection. If the file can't be found, or access is denied, or the data connection can't be opened, an appropriate error message is returned.

Examples:

	RETR JIM.TXT
	RETR ../HTTP/dogs.html

Notes: Single files only, wildcards not accepted.

See also:	PORT	-- Host/port for data connection.
	STOR	-- Send a file to the server.

STOR -- Store (upload) file.

Syntax: STOR [path/]<filename>

The STOR command requests the FTP server to accept data via the data connection and store it as a file with the specified name.

If the file specified in the pathname already exists at the server, it is overwritten by the new data. The overwrite doesn't take place until the file has been correctly received, which prevents a critical file being lost if the data connection fails.

Examples:

	STOR JIM.TXT
	STOR /FRED/DOG.EXE

See also: RETR -- Retrieve a file from the server.

RMD -- Remove Directory.

Syntax: RMD <pathname>

The RMD command deletes the directory specified by <pathname> from the FTP server, providing you are the owner of that directory and have write access.

Examples:

	RMD FRED
	RMD /JIM/BILL

See also: MKD -- Make directory

RNFR -- Rename From

Syntax: RNFR [path/]<filename>

The RNFR command specifies the old pathname of a file which is to be renamed, and must be immediately followed by an RNTO command. The two commands together cause a file to be renamed. If the file is not found the request is refused.

Examples:

	RNFR ../JIM.TXT
	RNFR /FRED/DOG.EXE

See also: RNTO -- Rename To

RNTO -- Rename To

Syntax: RNTO [path/]<filename>

The RNTO command specifies the new pathname of a file which is being renamed, and must immediately follow an RNFR command. The two commands together cause a file to be renamed.

If the new pathname isn't valid, the request is refused.

Examples:

	RNTO DOG.TXT
	RNTO /FRED/CAT.EXE

See also: RNFR -- Rename From.

STRU -- Specify File Structure.

Syntax: STRU <structure_code>

STRU specifies the internal structure of the files being transferred, i.e. how the data is organised within them. Structure codes are as follows:

	F - File       No record structure (contiguous bytes)
	R - Record     Collection of sequential records
	P - Page       File is composed of independent pages

The default structure, which is the only one currently implemented, is (F)ile. The command is included to prevent unnecessary error replies.

Example:

	STRU F   Sets (F)ile structure.

SYST -- Operating system enquiry.

Syntax: SYST

The SYST command is used to discover what type of operating system is being used on the server.

The first word of the reply is one of the agreed system names, in this case MSDOS. The rest of the reply gives the server version number and byte size.

TYPE -- Specifies the data representation type.

Syntax: TYPE <type_code>

The argument to the TYPE command specifies how the data is to be translated between storage and transfer. Type codes are as follows:

	A - ASCII      Text.  End of line is <CR><LF>
	I - Image      No translation.  Bytes stored as rcvd.
	L <bytesize>   Size of local storage bytes

Examples:

 
	TYPE A    Specifies Ascii type.
	TYPE L 8  Local byte size of 8 bits

USER -- Specify user name for login.

Syntax: USER <username>

The argument to the USER command is a string of up to 8 characters specifying the user's login name (usually callsign). The string must not contain spaces.

Users are not allowed access to the system without logging in.

If the username (or callsign) exists in the PASSWORD.SYS file the server sends a grid of 5x5 numbers (see PASS command) generated from the user's stored password. If the username is not found, an error message is sent instead, and access is denied.

The USER command must be immediately followed by the PASS command.

Examples:

	USER SYSOP    Enters login name as "SYSOP"
	USER G8PZT    Use callsign

Note: Because the FTP server allows you to use any string of characters as a name, you may set up different passwords for different login names, and these may be in addition to your callsign, which is the one used for ax25 sysop access.

See also: PASS -- Specify password.

XMKD, XPWD, XRMD -- Used by JNOS.

These are JNOS versions of MKD, PWD and RMD. In XRPi they function exactly like the usual commands.

See also

FTP-SRV(6) -- FTP Server.