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 Protocol. 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 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
supported. 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.
- -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
successfully 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 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.
- 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 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 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 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.
- 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
seconds. If seconds is omitted, the current inactivity timer
is printed.
- lcd [directory]
- 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.
- 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 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 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 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-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 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). 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.
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 outpattern, 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 authenticate 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 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.
- 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 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.
- 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 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 ``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 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, 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 partially transferred copy of remote-file
and the transfer is continued from the apparent point of failure.
This command is useful 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
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.
- 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
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
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 specified, the current type is printed. The default type is
network ASCII.
- umask [newmask]
- 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.
- 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 completed 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 (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 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 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
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
(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 incorrect transfers of binary files to and from 4.2BSD
servers using the ascii type. Avoid this problem by using the
binary image type.