ftp - ARPANET file transfer program
ftp [-v] [-d] [-i] [-n] [-g] [-k realm] [-f] [-x] [-u] [-t] [host]
FTP is the user interface to the ARPANET standard File Transfer Protocol. The program
allows a user to transfer files to and from a remote network site.
Options may be specified at the command line, or to the command interpreter.
-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 connection. If auto-
login is enabled, ftp will check the .netrc (see below) file in the user's 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 initial 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 authentication 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.
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 successfully authenticating.
-t Enables packet tracing.
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.
Supply 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
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 setting. 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 commands. 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 command must be sent
integrity protected, and must be proceeded by a successful ADAT command. Since
turning off integrity protection potentially allows an attacker to insert commands
onto the command channel, some FTP servers may refuse to honor this command.
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 suc-
ceeded, then this is the default protection level.
close Terminate the FTP session with the remote server, and return to the command inter-
preter. Any defined macros are erased.
Set the protection level on commands to protection-level. The valid protection
levels are ``clear'' for unprotected commands, ``safe'' for commands integrity pro-
tected by cryptographic checksum, and ``private'' for commands confidentiality and
integrity protected by encryption. If an ADAT command succeeded, 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 distinguished from a record delimiter only when cr is off.
Delete the file remote-file on the remote machine.
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.
A synonym for close.
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, sub-
ject 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 globbing 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 transferred. The size of a
data block is 1024 bytes.
Print an informative message about the meaning of command. If no argument is
given, ftp prints a list of the known commands.
Set the inactivity timer on the remote server to seconds seconds. If seconds is
omitted, the current inactivity timer is printed.
Change the working directory on the local machine. If no directory 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 systems 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.
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 charac-
ters in all defined macros. Macros remain defined until a close command is exe-
cuted. 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 `$' followed by an `i' signals that macro proces-
sor that the executing macro is to be looped. On the first pass `$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 `$'.
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 tar-
get local file for receiving mdir output.
Expand 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
will then be processed according to case, ntrans, and nmap settings. Files are
transferred into the local working directory, which can be changed with `lcd direc-
tory'; new local directories can be created with `! mkdir directory'.
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.
Set the file transfer mode to mode-name. The default mode is ``stream'' mode.
Show the last modification time of the file on the remote machine.
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.
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 considered 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-direc-
tory 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 spec-
ified, 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
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 non-UNIX remote computer 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
may have already been processed according to the ntrans and case settings). Vari-
able 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 [inpat-
tern] 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 file-
name. 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". Spaces may be included in out-
pattern, as in the example: `nmap $1 sed "s/ *$//" > $1'. Use the `\' character to
prevent special treatment of the `$','[',']', and `,' characters.
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 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.
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 authentica-
tion types which are locally supported. Once an authentication type is accepted,
an authentication protocol 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 user's Kerberos tickets to the remote host.
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 pas-
Set the protection level on data transfers to ``private''. Data transmissions are
confidentiality and integrity protected by encryption. If no ADAT command suc-
ceeded, then the only possible level is ``clear''.
prompt Toggle interactive prompting. Interactive prompting occurs during 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.
Set the protection level on data transfers to protection-level. The valid protec-
tion levels are ``clear'' for unprotected data transmissions, ``safe'' for data
transmissions integrity protected by cryptographic checksum, and ``private'' for
data transmissions 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
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 sec-
ondary 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 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, for-
mat, 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 partially transferred copy of remote-file and
the transfer is continued from the apparent point of failure. This command is use-
ful when transferring very large files over networks that are prone to dropping
Request help from the remote FTP server. If a command-name is specified it is sup-
plied to the server as well.
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 the immediately following get or put at the indicated marker. On UNIX sys-
tems, marker is usually a byte offset into the file.
Delete a directory on the remote machine.
Toggle 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 will be reported. Note that runique will not affect
local files generated 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.
Toggle the use of PORT commands. By default, ftp will attempt to use a PORT com-
mand when establishing a connection for each data transfer. The use of PORT com-
mands can prevent delays when performing multiple file transfers. If the PORT com-
mand fails, ftp will use the default data port. When the use of PORT commands is
disabled, no attempt will be made to use PORT commands for each data transfer.
This is useful for certain FTP implementations which do ignore PORT commands but,
incorrectly, indicate they've been accepted.
site arg1 [arg2] [...]
The arguments specified are sent, verbatim, to the remote FTP server as a SITE com-
Return size of file-name on remote machine.
status Show the current status of ftp.
Set the file transfer structure to struct-name. By default ``stream'' structure is
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.
Set the file transfer type to type-name. If no type is specified, the current type
is printed. The default type is network ASCII.
Set the default umask on the remote server to newmask. If newmask 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 connection
to the FTP server.
Toggle verbose mode. In verbose mode, all responses from the FTP server are dis-
played 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, ver-
bose is on.
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 trans-
fers will be immediately halted. Receiving transfers will be halted by sending a FTP pro-
tocol 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 pro-
cessing. 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 completed any local pro-
cessing 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
1. If the file name `-' is specified, stdin (for reading) or stdout (for writing) is
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 filename 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-10's and PDP-20's). Ftp supports the ascii and image types of file trans-
fer, 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:
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.
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 nor-
mally 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.
Identify a user on the remote machine. If this token is present, the auto-login
process will initiate a login using the specified name.
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.
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 addi-
tional account password, or the auto-login process will initiate an ACCT command if
it does not.
Define a macro. This token functions like the ftp macdef command 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 encoun-
tered. If a macro named init is defined, it is automatically executed as the last
step in the auto-login process.
Ftp utilizes the following environment variables.
HOME For default location of a .netrc file, if one exists.
SHELL For default shell.
Lunt, S. J., FTP Security Extensions, Internet Draft, November 1993.
The ftp command appeared in 4.2BSD.
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 incorrect transfers of binary files to and
from 4.2BSD servers using the ascii type. Avoid this problem by using the binary image