FTP – file transfer program Programa de transferencia de archivos

SYNOPSIS

ftp

[-pinegvd]

[host]


pftp

[-inegvd]

[host]

EXAMPLES

SEE ALSO

rcp(1),
scp(1),
cp(1),
ftpd(8),

DESCRIPTION

Ftp

is the user interface to the Internet

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.

-p

Use passive mode for data transfers. Allows use of ftp in environments where a firewall prevents connections from the outside world back to the client machine. Requires that the ftp server support the PASV command. This is the default now for all

clients (ftp and pftp) due to security concerns using the PORT transfer mode.
The flag is kept for compatibility only and has no effect anymore.

-i

Turns off interactive prompting during multiple file transfers.

-n

Restrains
ftp

from attempting auto-login upon initial connection.
If auto-login is enabled,
ftp

will check the
.netrc

(see netrc(5))

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.

-e

Disables command editing and history support, if it was compiled into the ftp executable. Otherwise, does nothing.
-g

Disables file name globbing.
-v

Verbose option forces
ftp
to show all responses from the remote server, as well as report on data transfer statistics.
-d

Enables debugging.

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 image 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.

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
sytem to
mode

close

Terminate the
FTP

session with the remote server, and
return to the command interpreter.
Any defined macros are erased.

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
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 ommitted, 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.

macdef macro-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 the
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 [local-file

]

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 a
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

]

, Ar 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

]

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-login

option is on (default),
ftp

will also attempt to automatically log the user in to
the
FTP

server (see below).

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.

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.

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 ommitted, 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, the
    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 (writes) from the 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 the
    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 (for
PDP -10’s

and
PDP -20’s

mostly).
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