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.
-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’, ..., ‘$9’ are replaced by any value resulting from the
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. In passive mode, the client
initiates the data connection by listening on the data port.
Passive mode may be necessary for operation from behind
firewalls which do not permit incoming connections.
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 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 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
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
incorrect transfers of binary files to and from 4.2BSD servers using
the ascii type. Avoid this problem by using the binary image type.
FTP(1)