ftp - file transfer program
ftp [-adfginpstvx] [-m GSS Mech] [-T timeout] [hostname [port]]
The ftp command is the user interface to the Internet standard File Transfer Protocol (FTP). ftp transfers files to and from a remote network site.
The host and optional port with which ftp is to communicate can be specified on the command line. If this is done, ftp immediately attempts to establish a connection to an FTP server on that host. Otherwise, ftp enters its command interpreter and awaits instructions from the user. When ftp is awaiting commands from the user, it displays the prompt ftp>.
The following options can be specified at the command line, or to the command interpreter:
Uses GSSAPI authentication only. If the authentication fails, this option closes the connection.
Forwards local security credentials to the remote server.
Disables filename “globbing”.
Turns off interactive prompting during multiple file transfers.
Specifies the GSS-API mechanism to use. The default is to use the kerberos_v5 mechanism. Supported alternatives are defined in /etc/gss/mech (see mech(5)).
Does not attempt “auto-login” upon initial connection. If auto-login is not disabled, ftp checks the .netrc file in the user's home directory for an entry describing an account on the remote machine. If no entry exists, ftp prompts for the login name of the account on the remote machine (the default is the login name on the local machine), and, if necessary, prompts for a password and an account with which to login.
Enables passive mode for data transfers. This command is useful when connecting to a remote host from behind a connection filtering firewall.
Skips the SYST command that is sent by default to all remote servers upon login. The system command is what enables the automatic use of binary mode rather than the protocol default ascii mode.
As some older servers cannot handle the ftp command, this directive is provided to allow interoperability with these servers.
Enables packet tracing (unimplemented).
Enables global connection timer, specified in seconds (decimal). There is a timer for the control connection that is reset when anything is sent to the server and disabled while the client is prompting for user input. Another independent timer is used to monitor incoming or outgoing data connections.
Shows all responses from the remote server, as well as report on data transfer statistics. This is turned on by default if ftp is running interactively with its input coming from the user's terminal.
Attempts to use GSSAPI for authentication and encryption. Data and Command channel protection is set to “private”.
The following commands can be specified to the command interpreter:
[ command ] Runs command as a shell command on the local machine. If no command is given, invokes an interactive shell.
Executes the macro macro-name that was defined with the macdef command. Arguments are passed to the macro unglobbed.
Supplies a supplemental password required by a remote system for access to resources once a login has been successfully completed. If no argument is included, the user is prompted for an account password in a non-echoing input mode.
Appends a local file to a file on the remote machine. If remote-file is not specified, the local file name is used, subject to alteration by any ntrans or nmap settings. File transfer uses the current settings for “representation type”, “file structure”, and “transfer mode”.
Sets the “representation type” to “network ASCII”. This is the default type.
Sounds a bell after each file transfer command is completed.
Sets the “representation type” to “image”.
Terminates the FTP session with the remote server and exit ftp. An EOF also terminates the session and exit.
Toggles remote computer file name case mapping during mget commands. When case is on (default is off), remote computer file names with all letters in uppercase are written in the local directory with the letters mapped to lowercase.
Changes the working directory on the remote machine to remote-directory.
Changes the remote machine working directory to the parent of the current remote machine working directory.
Sets the protection level on data transfers to “clear”. If no ADAT command succeeded, then this is the default protection level.
Terminates the FTP session with the remote server, and return to the command interpreter. Any defined macros are erased.
Toggles RETURN stripping during “network ASCII” type file retrieval. Records are denoted by a RETURN/LINEFEED sequence during “network ASCII” type file transfer. When cr is on (the default), RETURN characters are stripped from this sequence to conform with the UNIX system single LINEFEED record delimiter. Records on non-UNIX-system remote hosts can contain single LINEFEED characters; when an “network ASCII” type transfer is made, these LINEFEED characters can be distinguished from a record delimiter only when cr is off.
Deletes the file remote-file on the remote machine.
Toggles debugging mode. When debugging is on, ftp prints each command sent to the remote machine, preceded by the string ->.
Prints a listing of the directory contents in the directory, remote-directory, and, optionally, placing the output in local-file. If no directory is specified, the current working directory on the remote machine is used. If no local file is specified, or local-file is −, output is sent to the terminal.
A synonym for close.
Sets the carriage control format subtype of the “representation type” to format-name. The only valid format-name is non-print, which corresponds to the default “non-print” subtype.
Retrieves the remote-file and store it on the local machine. If the local file name is not specified, it is given the same name it has on the remote machine, subject to alteration by the current case, ntrans, and nmap settings. The current settings for “representation type”, “file structure”, and “transfer mode” are used while transferring the file.
Toggles filename expansion, or “globbing”, for mdelete, mget and mput. If globbing is turned off, filenames are taken literally.
Globbing for mput is done as in sh(1). For mdelete and mget, each remote file name is expanded separately on the remote machine, and the lists are not merged.
Expansion of a directory name is likely to be radically different from expansion of the name of an ordinary file: the exact result depends on the remote operating system and FTP server, and can be previewed with the command, mls remote-files −.
mget and mput are not meant to transfer entire directory subtrees of files. You can do this by transferring a tar(1) archive of the subtree (using a “representation type” of “image” as set by the binary command).
Toggles hash-sign (#) printing for each data block transferred. The size of a data block is 8192 bytes.
Prints an informative message about the meaning of command. If no argument is given, ftp prints a list of the known commands.
Changes the working directory on the local machine. If no directory is specified, the user's home directory is used.
By default, prints an abbreviated listing of the contents of a directory on the remote machine. This default behavior can be changed to make ls a synonym of the dir command. This change can be achieved by setting FTP_LS_SENDS_NLST to 'no' in /etc/default/ftp or in the environment. See ftp(5) for details.
The –a option lists all entries, including those that begin with a dot (.), which are normally not listed. The –l option lists files in long format, giving mode, number of links, owner, group, size in bytes, and time of last modification for each file. If the file is a special file, the size field instead contains the major and minor device numbers rather than a size. If the file is a symbolic link, the filename is printed followed by “→” and the pathname of the referenced file.
If remote-directory is left unspecified, the current working directory is used.
If no local file is specified, or if local-file is −, the output is sent to the terminal.
Defines a macro. Subsequent lines are stored as the macro macro-name. A null line (consecutive NEWLINE characters in a file or RETURN characters from the terminal) terminates macro input mode. There is a limit of 16 macros and 4096 total characters in all defined macros. Macros remain defined until a close command is executed.
The macro processor interprets $ and \ as special characters. A $ followed by a number (or numbers) is replaced by the corresponding argument on the macro invocation command line. A $ followed by an i signals that macro processor that the executing macro is to be looped. On the first pass, $i is replaced by the first argument on the macro invocation command line; on the second pass, it is replaced by the second argument, and so on. A \ followed by any character is replaced by that character. Use the \ to prevent special treatment of the $.
Deletes the remote-files on the remote machine.
Like dir, except multiple remote files can be specified. If interactive prompting is on, ftp prompts the user to verify that the last argument is indeed the target local file for receiving mdir output.
Expands the remote-files on the remote machine and do a get for each file name thus produced. See glob for details on the filename expansion. Resulting file names are processed according to case, ntrans, and nmap settings. Files are transferred into the local working directory, which can be changed with lcd directory. New local directories can be created with ! mkdir directory.
Makes a directory on the remote machine.
Like ls(1), except multiple remote files can be specified. If interactive prompting is on, ftp prompts the user to verify that the last argument is indeed the target local file for receiving mls output.
Sets the “transfer mode” to mode-name. The only valid mode-name is stream, which corresponds to the default “stream” mode. This implementation only supports stream, and requires that it be specified.
Expands wild cards in the list of local files given as arguments and do a put for each file in the resulting list. See glob for details of filename expansion. Resulting file names are processed according to ntrans and nmap settings.
Prints an abbreviated listing of the contents of a directory on the remote machine, listing only those files that can be retrieved by the get command, unless the –a or –l option is used. If remote-directory is left unspecified, the current working directory is used.
The –a option lists all entries, including those that begin with a dot (.), which are normally not listed. The –l option lists files in long format the same way it does when used with the ls command.
Sets or unsets the filename mapping mechanism. If no arguments are specified, the filename mapping mechanism is unset. If arguments are specified, remote filenames are mapped during mput commands and put commands issued without a specified remote target filename. If arguments are specified, local filenames are mapped during mget commands and get commands issued without a specified local target filename.
This command is useful when connecting to a non-UNIX-system remote host with different file naming conventions or practices. The mapping follows the pattern set by inpattern and outpattern. inpattern is a template for incoming filenames (which can have already been processed according to the ntrans and case settings). Variable templating is accomplished by including the sequences $1, $2, . . . , $9 in inpattern. Use \ to prevent this special treatment of the $ character. All other characters are treated literally, and are used to determine the nmap inpattern variable values.
For example, given inpattern $1.$2 and the remote file name mydata.data, $1 would have the value mydata, and $2 would have the value data.
The outpattern determines the resulting mapped filename. The sequences $1, $2, . . . , $9 are replaced by any value resulting from the inpattern template. The sequence $0 is replaced by the original filename. Additionally, the sequence [ seq1 , seq2 ] is replaced by seq1 if seq1 is not a null string; otherwise it is replaced by seq2.
For example, the command nmap $1.$2.$3 [$1,$2].[$2,file] would yield the output filename myfile.data for input filenames myfile.data and myfile.data.old, myfile.file for the input filename myfile, and myfile.myfile for the input filename .myfile. SPACE characters can be included in outpattern, as in the example nmap $1 | sed "s/ *$//" > $1. Use the \ character to prevent special treatment of the $, [, ], and ,, characters.
Sets or unsets the filename character translation mechanism. If no arguments are specified, the filename character translation mechanism is unset. If arguments are specified, characters in remote filenames are translated during mput commands and put commands issued without a specified remote target filename, and characters in local filenames are translated during mget commands and get commands issued without a specified local target filename.
This command is useful when connecting to a non-UNIX-system remote host with different file naming conventions or practices. Characters in a filename matching a character in inchars are replaced with the corresponding character in outchars. If the character's position in inchars is longer than the length of outchars, the character is deleted from the file name.
Only 16 characters can be translated when using the ntrans command under ftp. Use case (described above) if needing to convert the entire alphabet.
Establishes a connection to the specified host FTP server. An optional port number can be supplied, in which case, ftp attempts to contact an FTP server at that port. If the auto-login option is on (default setting), ftp also attempts to automatically log the user in to the FTP server.
Toggles passive mode. When passive mode is turned on, the ftp client sends the PASV command requesting that the FTP server open a port for the data connection and return the address of that port. The remote server listens on that port and the client connects to it. When passive mode is turned off, the ftp client sends the PORT command to the server specifying an address for the remote server to connect back to. Passive mode is useful when the connections to the ftp client are controlled, for example, when behind a firewall. When connecting to an IPv6-enabled FTP server, EPSV can be used in place of PASV and EPRT in place of PORT.
Sets the protection level on data transfers to “private”. Data transmissions are confidentiality- and integrity-protected by encryption. If no ADAT command succeeded, then the only possible level is “clear”.
Toggles interactive prompting. Interactive prompting occurs during multiple file transfers to allow the user to selectively retrieve or store files. By default, prompting is turned on. If prompting is turned off, any mget or mput transfers all files, and any mdelete deletes all files.
Sets the protection level on data transfers to protection-level. The valid protection levels are “clear” for unprotected data transmissions, “safe” for data transmissions that are integrity-protected by cryptographic checksum, and “private” for data transmissions that are confidentiality- and integrity-protected by encryption. If no ADAT command succeeded, then the only possible level is “clear”. If no level is specified, the current level is printed. The default protection level is “clear”.
Executes an FTP command on a secondary control connection. This command allows simultaneous connection to two remote FTP servers for transferring files between the two servers. The first proxy command should be an open, to establish the secondary control connection. Enter the command proxy ? to see other FTP commands executable on the secondary connection.
The following commands behave differently when prefaced by proxy: open does not define new macros during the auto-login process, close does not erase existing macro definitions, get and mget transfer files from the host on the primary control connection to the host on the secondary control connection, and put, mputd, and append transfer files from the host on the secondary control connection to the host on the primary control connection.
Third party file transfers depend upon support of the PASV command by the server on the secondary control connection.
Stores a local file on the remote machine. If remote-file is left unspecified, the local file name is used after processing according to any ntrans or nmap settings in naming the remote file. File transfer uses the current settings for “representation type”, “file structure”, and “transfer mode”.
Prints the name of the current working directory on the remote machine.
A synonym for bye.
Sends the arguments specified, verbatim, to the remote FTP server. A single FTP reply code is expected in return. (The remotehelp command displays a list of valid arguments.)
quote should be used only by experienced users who are familiar with the FTP protocol.
A synonym for get.
The reget command acts like get, except that if local-file exists and is smaller than remote-file, local-file is presumed to be a partially transferred copy of remote-file and the transfer is continued from the apparent point of failure. This command is useful when transferring large files over networks that are prone to dropping connections.
Requests help from the remote FTP server. If a command-name is specified it is supplied to the server as well.
Renames the file from on the remote machine to have the name to.
Clears reply queue. This command re-synchronizes command/reply sequencing with the remote FTP server. Resynchronization can be necessary following a violation of the FTP protocol by the remote server.
Restarts the immediately following get or put at the indicated marker. On UNIX systems, marker is usually a byte offset into the file. When followed by an mget, the restart applies to the first get performed. Specifying a marker of 0 clears the restart marker. If no argument is specified, the current restart status is displayed.
Deletes a directory on the remote machine.
Toggles storing of files on the local system with unique filenames. If a file already exists with a name equal to the target local filename for a get or mget command, a .1 is appended to the name. If the resulting name matches another existing file, a .2 is appended to the original name. If this process continues up to .99, an error message is printed, and the transfer does not take place. The generated unique filename is reported. runique does not affect local files generated from a shell command. The default value is off.
Sets the protection level on data transfers to “safe”. Data transmissions are integrity-protected by cryptographic checksum. If no ADAT command succeeded, then the only possible level is “ clear”.
A synonym for put.
Toggles the use of PORT commands. By default, ftp attempts to use a PORT command when establishing a connection for each data transfer. The use of PORT commands can prevent delays when performing multiple file transfers. If the PORT command fails, ftp uses the default data port. When the use of PORT commands is disabled, no attempt is made to use PORT commands for each data transfer. This is useful when connected to certain FTP implementations that ignore PORT commands but incorrectly indicate they have been accepted.
Sends the arguments specified, verbatim, to the remote FTP server as a SITE command.
Show the current status of ftp.
Sets the file structure to struct-name. The only valid struct-name is file, which corresponds to the default “file” structure. The implementation only supports file, and requires that it be specified.
Toggles storing of files on remote machine under unique file names. The remote FTP server must support the STOU command for successful completion. The remote server reports the unique name. Default value is off.
Sets the TCP window size to be used for data connections. Specifying a size of 0 stops the explicit setting of the TCP window size on data connections. If no argument is specified, the current setting is displayed.
Sets the “representation type” to that needed to talk to TENEX machines.
Toggles packet tracing (unimplemented).
Sets the “representation type” to type-name. The valid type-names are ascii for “network ASCII”, binary or image for “image”, and tenex for “local byte size” with a byte size of 8 (used to talk to TENEX machines). If no type is specified, the current type is printed. The default type is “network ASCII”.
Identify yourself to the remote FTP server. If the password is not specified and the server requires it, ftp prompts the user for it (after disabling local echo). If an account field is not specified, and the FTP server requires it, the user is prompted for it. If an account field is specified, an account command is relayed to the remote server after the login sequence is completed if the remote server did not require it for logging in. Unless ftp is invoked with “auto-login” disabled, this process is done automatically on initial connection to the FTP server.
Toggles verbose mode. In verbose mode, all responses from the FTP server are displayed to the user. In addition, if verbose mode is on, when a file transfer completes, statistics regarding the efficiency of the transfer are reported. By default, verbose mode is on if ftp's commands are coming from a terminal, and off otherwise.
A synonym for help.
Command arguments which have embedded spaces can be quoted with quote (") marks.
If any command argument which is not indicated as being optional is not specified, ftp prompts for that argument.
To abort a file transfer, use the terminal interrupt key. Sending transfers is immediately halted. Receiving transfers are halted by sending an FTP protocol ABOR command to the remote server, and discarding any further data received. The speed at which this is accomplished depends upon the remote server's support for ABOR processing. If the remote server does not support the ABOR command, an ftp> prompt does not appear until the remote server has completed sending the requested file.
The terminal interrupt key sequence is ignored when ftp has completed any local processing and is awaiting a reply from the remote server. A long delay in this mode can result from the ABOR processing described above, or from unexpected behavior by the remote server, including violations of the ftp protocol. If the delay results from unexpected remote server behavior, the local ftp program must be killed by hand.
Local files specified as arguments to ftp commands are processed according to the following rules.
If the file name − is specified, the standard input (for reading) or standard output (for writing) is used.
If the first character of the file name is |, the remainder of the argument is interpreted as a shell command. ftp then forks a shell, using popen(3C) with the argument supplied, and reads (writes) from the standard output (standard input) of that shell. If the shell command includes SPACE characters, the argument must be quoted; for example, | ls – lt. A particularly useful example of this mechanism is: "dir | more".
Failing the above checks, if globbing is enabled, local file names are expanded according to the rules used in the sh(1); see the glob command. If the ftp command expects a single local file (for example, put), only the first filename generated by the globbing operation is used.
For mget commands and get commands with unspecified local file names, the local filename is the remote filename, which can be altered by a case, ntrans, or nmap setting. The resulting filename can then be altered if runique is on.
For mput commands and put commands with unspecified remote file names, the remote filename is the local filename, which can be altered by a ntrans or nmap setting. The resulting filename can then be altered by the remote server if sunique is on.
The FTP specification specifies many parameters which can affect a file transfer.
The “representation type” can be one of “network ASCII”, “EBCDIC”, “image”, or “local byte size” with a specified byte size (for PDP-10's and PDP-20's mostly). The “network ASCII” and “EBCDIC” types have a further subtype which specifies whether vertical format control (NEWLINE characters, form feeds, and so on) are to be passed through (“non-print”), provided in TELNET format (“ TELNET format controls”), or provided in ASA (FORTRAN) (“carriage control (ASA)”) format. ftp supports the “network ASCII” (subtype “non-print” only) and “image” types, plus “local byte size” with a byte size of 8 for communicating with TENEX machines.
The “file structure” can be one of file (no record structure), record, or page. ftp supports only the default value, which is file.
The “transfer mode” can be one of stream, block, or compressed. ftp supports only the default value, which is stream.
See attributes(7) for descriptions of the following attributes:
Allman, M., Ostermann, S., and Metz, C. RFC 2428, FTP Extensions for IPv6 and NATs. The Internet Society. September 1998.
Lunt, S. J. RFC 2228, FTP Security Extensions. Internet Draft. November 1993.
Postel, Jon, and Joyce Reynolds. RFC 959, File Transfer Protocol (FTP). Network Information Center. October 1985.
Piscitello, D. RFC 1639, FTP Operation Over Big Address Records (FOOBAR). Network Working Group. June 1994.
Failure to log in can arise from an explicit denial by the remote FTP server because the account is listed in /etc/ftpusers. See ftpusers(5).
Correct execution of many commands depends upon proper behavior by the remote server.
An error in the treatment of carriage returns in the 4.2 BSD code handling transfers with a “representation type” of “network ASCII” has been corrected. This correction can result in incorrect transfers of binary files to and from 4.2 BSD servers using a “representation type” of “network ASCII”. Avoid this problem by using the “image” type.