NAME ftp - ARPANET file transfer program
SYNOPSIS ftp [-v] [-d] [-i] [-n] [-g] [-k realm] [-f] [-x] [-u] [-t] [host]
DESCRIPTION FTP is the user interface to the ARPANET standard File Transfer Proto- col. The program allows a user to transfer files to and from a remote network site.
OPTIONS Options may be specified at the command line, or to the command inter- preter.
-v Verbose option forces ftp to show all responses from the remote server, as well as report on data transfer statistics.
-n Restrains ftp from attempting auto-login upon initial con- nection. If auto-login is enabled, ftp will check the .netrc (see below) file in the users home directory for an entry describing an account on the remote machine. If no entry exists, ftp will prompt for the remote machine login name (default is the user identity on the local machine), and, if necessary, prompt for a password and an account with which to login.
-u Restrains ftp from attempting auto-authentication upon ini- tial connection. If auto-authentication is enabled, ftp attempts to authenticate to the FTP server by sending the AUTH command, using whichever authentication types are locally sup- ported. Once an authentication type is accepted, an authentica- tion protocol will proceed by issuing ADAT commands. This option also disables auto-login.
-i Turns off interactive prompting during multiple file transfers.
-d Enables debugging.
-g Disables file name globbing.
-k realm When using Kerberos v4 authentication, gets tickets in realm.
-f Causes credentials to be forwarded to the remote host.
-x Causes the client to attempt to negotiate encryption (data and command protection levels private) immediately after suc- cessfully authenticating.
-t Enables packet tracing.
COMMANDS The client host with which ftp is to communicate may be specified on the command line. If this is done, ftp will immediately attempt to establish a connection to an FTP server on that host; otherwise, ftp will enter its command interpreter and await instructions from the user. When ftp is awaiting commands from the user the prompt ftp> is provided to the user. The following commands are recognized by ftp:
! [command] [args]] Invoke an interactive shell on the local machine. If there are arguments, the first is taken to be a command to execute directly, with the rest of the arguments as its arguments.
$ macro-name [args] Execute the macro macro-name that was defined with the macdef command. Arguments are passed to the macro unglobbed.
account [passwd] Supply a supplemental password required by a remote system for access to resources once a login has been successfully com- pleted. If no argument is included, the user will be prompted for an account password in a non-echoing input mode.
append local-file [remote-file] Append a local file to a file on the remote machine. If remote- file is left unspecified, the local file name is used in naming the remote file after being altered by any ntrans or nmap set- ting. File transfer uses the current settings for type, format, mode, and structure.
ascii Set the file transfer type to network ASCII . This is the default type.
bell Arrange that a bell be sounded after each file transfer command is completed.
binary Set the file transfer type to support binary file transfer.
bye Terminate the FTP session with the remote server and exit ftp. An end of file will also terminate the session and exit.
case Toggle remote computer file name case mapping during mget com- mands. When case is on (default is off), remote computer file names with all letters in upper case are written in the local directory with the letters mapped to lower case.
ccc Turn off integrity protection on the command channel. This com- mand must be sent integrity protected, and must be proceeded by a successful ADAT command. Since turning off integrity protec- tion potentially allows an attacker to insert commands onto the command channel, some FTP servers may refuse to honor this com- mand.
cd remote-directory Change the working directory on the remote machine to remote- directory.
cdup Change the remote machine working directory to the parent of the current remote machine working directory.
chmod mode file-name Change the permission modes of the file file-name on the remote system to mode.
clear Set the protection level on data transfers to clear. If no ADAT command succeeded, then this is the default protection level.
close Terminate the FTP session with the remote server, and return to the command interpreter. Any defined macros are erased.
cprotect [protection-level] Set the protection level on commands to protection-level. The valid protection levels are clear for unprotected commands, safe for commands integrity protected by cryptographic checksum, and private for commands confidentiality and integrity protected by encryption. If an ADAT command suc- ceeded, then the default command protection level is safe, otherwise the only possible level is clear. If no level is specified, the current level is printed. cprotect clear is equivalent to the ccc command.
cr Toggle carriage return stripping during ascii type file retrieval. Records are denoted by a carriage return/linefeed sequence during ascii type file transfer. When cr is on (the default), carriage returns are stripped from this sequence to conform with the UNIX single linefeed record delimiter. Records on non-UNIX remote systems may contain single linefeeds; when an ascii type transfer is made, these linefeeds may be distin- guished from a record delimiter only when cr is off.
delete remote-file Delete the file remote-file on the remote machine.
debug [debug-value] Toggle debugging mode. If an optional debug-value is specified it is used to set the debugging level. When debugging is on, ftp prints each command sent to the remote machine, preceded by the string -->
dir [remote-directory] [local-file] Print a listing of the directory contents in the directory, remote-directory, and, optionally, placing the output in local- file. If interactive prompting is on, ftp will prompt the user to verify that the last argument is indeed the target local file for receiving dir output. 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 comes to the terminal.
disconnect A synonym for close.
form format Set the file transfer form to format. The default format is file.
get remote-file [local-file] Retrieve the file 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 type, form, mode, and structure are used while transferring the file.
glob Toggle filename expansion for mdelete, mget, and mput. If glob- bing is turned off with glob, the file name arguments are taken literally and not expanded. Globbing for mput is done as in csh(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 different from expansion of the name of an ordinary file: the exact result depends on the foreign operating system and ftp server, and can be previewed by doing mls remote-files - Note: mget and mput are not meant to transfer entire directory subtrees of files. That can be done by transferring a tar(1) archive of the subtree (in binary mode).
hash Toggle hash-sign ( # ) printing for each data block trans- ferred. The size of a data block is 1024 bytes.
help [command] Print an informative message about the meaning of command. If no argument is given, ftp prints a list of the known commands.
idle [seconds] Set the inactivity timer on the remote server to seconds sec- onds. If seconds is omitted, the current inactivity timer is printed.
lcd [directory] Change the working directory on the local machine. If no direc- tory is specified, the user s home directory is used.
ls [remote-directory] [local-file] Print a listing of the contents of a directory on the remote machine. The listing includes any system-dependent information that the server chooses to include; for example, most UNIX sys- tems will produce output from the command ls -l. (See also nlist.) If remote-directory is left unspecified, the current working directory is used. If interactive prompting is on, ftp will prompt the user to verify that the last argument is indeed the target local file for receiving ls output. If no local file is specified, or if local-file is -, the output is sent to the terminal.
macdefmacro-name Define a macro. Subsequent lines are stored as the macro macro- name; a null line (consecutive newline characters in a file or carriage returns 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 $.
mdelete [remote-files] Delete remote-files on the remote machine.
mdir remote-files local-file Like dir, except multiple remote files may be specified. If interactive prompting is on, ftp will prompt the user to verify that the last argument is indeed the target local file for receiving mdir output.
mget remote-files Expand the remote-files on the remote machine and do a get for each file name thus produced. See glob for details on the file- name expansion. Resulting file names will then be processed according to case, ntrans, and nmap settings. Files are trans- ferred into the local working directory, which can be changed with lcd directory; new local directories can be created with ! mkdir directory.
mkdir directory-name Make a directory on the remote machine.
mls remote-files local-file Like nlist, except multiple remote files may be specified, and the local-file must be specified. If interactive prompting is on, ftp will prompt the user to verify that the last argument is indeed the target local file for receiving mls output.
mode [mode-name] Set the file transfer mode to mode-name. The default mode is stream mode.
modtime file-name Show the last modification time of the file on the remote machine.
mput local-files Expand 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 will then be processed according to ntrans and nmap settings.
newer file-name Get the file only if the modification time of the remote file is more recent that the file on the current system. If the file does not exist on the current system, the remote file is consid- ered newer. Otherwise, this command is identical to get.
nlist [remote-directory] [local-file] Print a list of the files in a directory on the remote machine. If remote-directory is left unspecified, the current working directory is used. If interactive prompting is on, ftp will prompt the user to verify that the last argument is indeed the target local file for receiving nlist output. If no local file is specified, or if local-file is -, the output is sent to the terminal.
nmap [inpattern outpattern] Set or unset 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 tar- get 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 non-UNIX remote computer with different file nam- ing conventions or practices. The mapping follows the pattern set by inpattern and outpattern. [Inpattern] is a template for incoming filenames (which may 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, inpattern template. The sequence $0 is replace by the original filename. Addi- tionally, 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 file- names "myfile.data" and "myfile.data.old", "myfile.file" for the input filename "myfile", and "myfile.myfile" for the input file- name ".myfile". Spaces may be included in outpattern, as in the example: nmap $1 sed "s/ *$//" > $1. Use the character to prevent special treatment of the $,[,] , and , charac- ters.
ntrans [inchars [outchars]] Set or unset 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. If arguments are specified, 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 remote computer with different file naming conventions or practices. Characters in a filename matching a character in inchars are replaced with the corre- sponding 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.
open host [port] [-forward] Establish a connection to the specified host FTP server. An optional port number may be supplied, in which case, ftp will attempt to contact an FTP server at that port. If the auto- authenticate option is on (default), ftp will attempt to authen- ticate to the FTP server by sending the AUTH command, using whichever authentication types which are locally supported. Once an authentication type is accepted, an authentication pro- tocol will proceed by issuing ADAT commands. If the auto-login option is on (default), ftp will also attempt to automatically log the user in to the FTP server (see below). If the -forward option is specified, ftp will forward a copy of the users Ker- beros tickets to the remote host.
passive Toggle passive data transfer mode off. In passive mode, the client initiates the data connection by connecting to the data port. Passive mode is often necessary for operation from behind firewalls which do not permit incoming connections, but may need to be disabled if you connect to an FTP server which does not support passive operation.
private Set 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 possi- ble level is clear.
prompt Toggle interactive prompting. Interactive prompting occurs dur- ing multiple file transfers to allow the user to selectively retrieve or store files. If prompting is turned off (default is on), any mget or mput will transfer all files, and any mdelete will delete all files.
protect [protection-level] Set the protection level on data transfers to protection-level. The valid protection levels are clear for unprotected data transmissions, safe for data transmissions integrity pro- tected by cryptographic checksum, and private for data transmissions confidentiality and integrity protected by encryp- tion. 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.
proxy ftp-command Execute 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 com- mands executable on the secondary connection. The following commands behave differently when prefaced by proxy: open will not define new macros during the auto-login process, close will 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, mput, 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 ftp protocol PASV command by the server on the secondary control connection.
put local-file [remote-file] Store 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 type, format, mode, and structure.
pwd Print the name of the current working directory on the remote machine.
quit A synonym for bye.
quote arg1 [arg2] [...] The arguments specified are sent, verbatim, to the remote FTP server.
recv remote-file [local-file] A synonym for get.
reget remote-file [local-file] Reget acts like get, except that if local-file exists and is smaller than remote-file, local-file is presumed to be a par- tially transferred copy of remote-file and the transfer is con- tinued from the apparent point of failure. This command is use- ful when transferring very large files over networks that are prone to dropping connections.
remotehelp [command-name] Request help from the remote FTP server. If a command-name is specified it is supplied to the server as well.
remotestatus [file-name] With no arguments, show status of remote machine. If file-name is specified, show status of file-name on remote machine.
rename [from] [to] Rename the file from on the remote machine, to the file to.
reset Clear reply queue. This command re-synchronizes command/reply sequencing with the remote ftp server. Resynchronization may be necessary following a violation of the ftp protocol by the remote server.
restart marker Restart the immediately following get or put at the indicated marker. On UNIX systems, marker is usually a byte offset into the file.
rmdir directory-name Delete a directory on the remote machine.
runique Toggle storing of files on the local system with unique file- names. 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 con- tinues up to ".99", an error message is printed, and the trans- fer does not take place. The generated unique filename will be reported. Note that runique will not affect local files gener- ated from a shell command (see below). The default value is off.
safe Set 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.
send local-file [remote-file] A synonym for put.
sendport Toggle the use of PORT commands. By default, ftp will attempt 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 will use the default data port. When the use of PORT com- mands is disabled, no attempt will be made to use PORT commands for each data transfer. This is useful for certain FTP imple- mentations which do ignore PORT commands but, incorrectly, indi- cate theyve been accepted.
site arg1 [arg2] [...] The arguments specified are sent, verbatim, to the remote FTP server as a SITE command.
size file-name Return size of file-name on remote machine.
status Show the current status of ftp.
struct struct-name Set the file transfer structure to struct-name. By default stream structure is used.
sunique Toggle storing of files on remote machine under unique file names. Remote ftp server must support ftp protocol STOU command for successful completion. The remote server will report unique name. Default value is off.
system Show the type of operating system running on the remote machine.
tenex Set the file transfer type to that needed to talk to TENEX machines.
trace Toggle packet tracing.
type [type-name] Set the file transfer type to type-name. If no type is speci- fied, the current type is printed. The default type is network ASCII.
umask [newmask] Set the default umask on the remote server to newmask. If new- mask is omitted, the current umask is printed.
user user-name [password] [account] Identify yourself to the remote FTP server. If the password is not specified and the server requires it, ftp will prompt the user for it (after disabling local echo). If an account field is not specified, and the FTP server requires it, the user will be prompted for it. If an account field is specified, an account command will be 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 connec- tion to the FTP server.
verbose Toggle verbose mode. In verbose mode, all responses from the FTP server are displayed to the user. In addition, if verbose is on, when a file transfer completes, statistics regarding the efficiency of the transfer are reported. By default, verbose is on.
? [command] A synonym for help.
Command arguments which have embedded spaces may be quoted with quote " marks.
ABORTING A FILE TRANSFER To abort a file transfer, use the terminal interrupt key (usually Ctrl- C). Sending transfers will be immediately halted. Receiving transfers will be halted by sending a 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 will not appear until the remote server has completed sending the requested file.
The terminal interrupt key sequence will be ignored when ftp has com- pleted any local processing and is awaiting a reply from the remote server. A long delay in this mode may 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.
FILE NAMING CONVENTIONS Files specified as arguments to ftp commands are processed according to the following rules.
1. If the file name - is specified, stdin (for reading) or stdout (for writing) is used.
2. 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(3) with the argument supplied, and reads from (writes to) stdout (stdin). If the shell command includes spaces, the argument must be quoted; e.g. " ls -lt". A particularly useful example of this mechanism is: dir more.
3. Failing the above checks, if globbing is enabled, local file names are expanded according to the rules used in csh(1); c.f. the glob command. If the ftp command expects a single local file (.e.g. put), only the first filename generated by the globbing operation is used.
4. For mget commands and get commands with unspecified local file names, the local filename is the remote filename, which may be altered by a case, ntrans, or nmap setting. The resulting file- name may then be altered if runique is on.
5. For mput commands and put commands with unspecified remote file names, the remote filename is the local filename, which may be altered by a ntrans or nmap setting. The resulting filename may then be altered by the remote server if sunique is on.
FILE TRANSFER PARAMETERS The FTP specification specifies many parameters which may affect a file transfer. The type may be one of ascii, image (binary), ebcdic, and local byte size (mostly for PDP-10s and PDP-20 s). Ftp supports the ascii and image types of file transfer, plus local byte size 8 for tenex mode transfers.
Ftp supports only the default values for the remaining file transfer parameters: mode, form, and struct.
THE .netrc FILE The .netrc file contains login and initialization information used by the auto-login process. It resides in the user s home directory. The following tokens are recognized; they may be separated by spaces, tabs, or new-lines:
machine name Identify a remote machine name. The auto-login process searches the .netrc file for a machine token that matches the remote machine specified on the ftp command line or as an open command argument. Once a match is made, the subsequent .netrc tokens are processed, stopping when the end of file is reached or another machine or a default token is encountered.
default This is the same as machine name except that default matches any name. There can be only one default token, and it must be after all machine tokens. This is normally used as:
default login anonymous password user@site
thereby giving the user automatic anonymous ftp login to machines not specified in .netrc. This can be overridden by using the -n flag to disable auto-login.
login name Identify a user on the remote machine. If this token is present, the auto-login process will initiate a login using the specified name.
password string Supply a password. If this token is present, the auto-login process will supply the specified string if the remote server requires a password as part of the login process. Note that if this token is present in the .netrc file for any user other than anonymous, ftp will abort the auto-login process if the .netrc is readable by anyone besides the user.
account string Supply an additional account password. If this token is present, the auto-login process will supply the specified string if the remote server requires an additional account password, or the auto-login process will initiate an ACCT command if it does not.
macdef name Define a macro. This token functions like the ftp macdef com- mand functions. A macro is defined with the specified name; its contents begin with the next .netrc line and continue until a null line (consecutive new-line characters) is encountered. If a macro named init is defined, it is automatically executed as the last step in the auto-login process.
ENVIRONMENT Ftp utilizes the following environment variables.
HOME For default location of a .netrc file, if one exists.
SHELL For default shell.
SEE ALSO ftpd(8)
Lunt, S. J., FTP Security Extensions, Internet Draft, November 1993.
HISTORY The ftp command appeared in 4.2BSD.
BUGS Correct execution of many commands depends upon proper behavior by the remote server.
An error in the treatment of carriage returns in the 4.2BSD ascii-mode transfer code has been corrected. This correction may result in incor- rect transfers of binary files to and from 4.2BSD servers using the ascii type. Avoid this problem by using the binary image type.