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 com-
mand 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 ini-
tial 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 authenti-
cation types are locally supported. Once an authenti-
cation 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 ses-
sion 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 turn-
ing 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 direc-
tory, 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 argu-
ment 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 for-
mat 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. Glob-
bing 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 com-
mand. 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 work-
ing directory is used. If interactive prompting is on,
ftp will prompt the user to verify that the last argu-
ment 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 ter-
minal) 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 speci-
fied. 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 speci-
fied, 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 sys-
tem, 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 speci-
fied, 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 argu-
ments are specified, local filenames are mapped during
mget commands and get commands issued without a speci-
fied local target filename. This command is useful
when connecting to non-UNIX remote computer with dif-
ferent file naming conventions or practices. The map-
ping follows the pattern set by inpattern and outpat-
tern. [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',
..., `$9' in inpattern. Use `\' to prevent this spe-
cial treatment of the `$' character. All other charac-
ters 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 exam-
ple: `nmap $1 sed "s/ *$//" > $1'. Use the `\' charac-
ter to prevent special treatment of the `$','[',']',
and `,' characters.
ntrans [inchars [outchars]]
Set or unset the filename character translation mechan-
ism. If no arguments are specified, the filename char-
acter 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 argu-
ments are specified, characters in local filenames are
translated during mget commands and get commands issued
without a specified local target filename. This com-
mand is useful when connecting to a non-UNIX remote
computer with different file naming conventions or
practices. Characters in a filename matching a charac-
ter 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 speci-
fied, 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 com-
mand 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 crypto-
graphic checksum, and ``private'' for data transmis-
sions 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 connec-
tion. 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 defini-
tions, 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 set-
tings in naming the remote file. File transfer uses
the current settings for type, format, mode, and struc-
ture.
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 viola-
tion 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 crypto-
graphic 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 con-
nection for each data transfer. The use of PORT com-
mands 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 proto-
col 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 com-
mand 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 com-
pletes, 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 viola-
tions of the ftp protocol. If the delay results from unex-
pected 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 com-
mand 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 set-
ting. 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 informa-
tion 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, stop-
ping 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 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 over-
ridden 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 addi-
tional 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 mac-
def 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 correc-
tion 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.
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