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.\"	@(#)ftp.1	8.3 (Berkeley) 10/9/94
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.\" Copyright (c) 2015 Sunil Nimmagadda <sunil@openbsd.org>
.\"
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.Dd $Mdocdate: May 12 2019 $
.Dt FTP 1
.Os
.Sh NAME
.Nm ftp
.Nd Internet file transfer program
.Sh SYNOPSIS
.Nm
.Op Fl 46AVv
.Op Fl D Ar title
.Op Ar host Op Ar port
.Nm
.Op Fl 46ACMV
.Op Fl D Ar title
.Op Fl o Ar output
.Op Fl S Ar tls_options
.Op Fl U Ar useragent
.Op Fl w Ar seconds
.Ar url ...
.Sh DESCRIPTION
.Nm
is the user interface to the Internet standard File Transfer
Protocol (FTP).
The program allows a user to transfer files to and from a
remote network site.
.Pp
The latter usage format will fetch a file using either the
FTP, HTTP or HTTPS protocols into the current directory.
This is ideal for scripts.
Refer to
.Sx AUTO-FETCHING FILES
below for more information.
.Pp
The options are as follows:
.Bl -tag -width Ds
.It Fl 4
Forces
.Nm
to use IPv4 addresses only.
.It Fl 6
Forces
.Nm
to use IPv6 addreses only.
.It Fl A
Force active mode FTP.
By default,
.Nm
will try to use passive mode FTP and fall back to active mode
if passive is not supported by the server.
This option causes
.Nm
to always use an active connection.
It is only useful for connecting
to very old servers that do not implement passive mode properly.
.It Fl C
Continue a previously interrupted file transfer.
.Nm
will continue transferring from an offset equal to the length of file.
.Pp
Resuming HTTP(S) transfers are only supported if the remote server supports the
.Dq Range
header.
.It Fl D Ar title
Specify a short title for the start of the progress bar.
.It Fl M
Causes
.Nm
to never display the progress meter in cases where it would do so by default.
.It Fl o Ar output
When fetching a file or URL, save the contents in
.Ar output .
To make the contents go to stdout, use `-' for
.Ar output .
.It Fl S Ar tls_options
TLS options to use with HTTPS transfers.
The following settings are available:
.Bl -tag -width Ds
.It Cm cafile Ns = Ns Ar /path/to/cert.pem
PEM encoded file containing CA certificates used for certificate validation.
.It Cm capath Ns = Ns Ar /path/to/certs/
Directory containing PEM encoded CA certificates used for certificate
validation.
.It Cm ciphers Ns = Ns Ar cipher_list
Specify the list of ciphers that will be used by
.Nm .
See the
.Xr openssl 1
.Cm ciphers
subcommand.
.It Cm depth Ns = Ns Ar max_depth
Maximum depth of the certificate chain allowed when performing validation.
.It Cm dont
Don't perform server certificate validation.
.It Cm protocols Ns = Ns Ar string
Specify the TLS protocols to use.
If not specified the value
.Qq all
is used.
Refer to the
.Xr tls_config_parse_protocols 3
function for other valid protocol string values.
.It Cm muststaple
Require the server to present a valid OCSP stapling in the TLS handshake.
.It Cm noverifytime
Disable validation of certificate times and OCSP validation.
.It Cm session Ns = Ns Ar /path/to/session
Specify a file to use for TLS session data.
If this file has a non-zero length, the session data will be read from this file
and the client will attempt to resume the TLS session with the server.
Upon completion of a successful TLS handshake this file will be updated with
new session data, if available.
This file will be created if it does not already exist.
.El
.Pp
By default, server certificate validation is performed, and if it fails
.Nm
will abort.
If no
.Cm cafile
or
.Cm capath
setting is provided,
.Pa /etc/ssl/cert.pem
will be used.
.It Fl U Ar useragent
Set
.Ar useragent
as the User-Agent for HTTP(S) URL requests.
If not specified, the default User-Agent is
.Dq OpenBSD ftp .
.It Fl V
Disable verbose mode.
.It Fl w Ar seconds
Abort a slow connection after
.Ar seconds .
.El
.Pp
The host with which
.Nm
is to communicate may be specified on the command line.
If this is done,
.Nm
will immediately attempt to establish a connection to an
FTP server on that host; otherwise,
.Nm
will enter its command interpreter and await instructions
from the user.
When
.Nm
is awaiting commands, the prompt
.Dq ftp\*(Gt
is provided to the user.
The following commands are recognized
by
.Nm :
.Bl -tag -width Fl
.It Ic open Ar host Op Ar port
Establish a connection to the specified
.Ar host
FTP server.
An optional port number may be supplied,
in which case
.Nm
will attempt to contact an FTP server at that port.
.It Ic close
Terminate the FTP session with the remote server and
return to the command interpreter.
.It Ic help Op Ar command
Print an informative message about the meaning of
.Ar command .
If no argument is given,
.Nm
prints a list of the known commands.
.It Ic \&? Op Ar command
A synonym for
.Ic help .
.It Ic quit
Terminate the FTP session with the remote server and exit
.Nm .
.It Ic exit
A synonym for
.Ic quit .
.It Ic ls Op Ar remote-directory Op Ar 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
.Ux
systems will produce output from the command
.Ql ls -l .
If
.Ar remote-directory
is left unspecified, the current working directory is used.
If no local file is specified, or if
.Ar local-file
is
.Sq - ,
the output is sent to the terminal.
.It Ic nlist Op Ar remote-directory Op Ar local-file
Print a list of the files in a
directory on the remote machine.
If
.Ar remote-directory
is left unspecified, the current working directory is used.
If no local file is specified, or if
.Ar local-file
is
.Sq - ,
the output is sent to the terminal.
Note that on some servers, the
.Ic nlist
command will only return information on normal files (not directories
or special files).
.It Ic pwd
Print the name of the current working directory on the remote
machine.
.It Ic cd Ar remote-directory
Change the working directory on the remote machine
to
.Ar remote-directory .
.It Ic get Ar remote-file Op Ar local-file
Retrieve the
.Ar 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.
.It Ic passive Op Ic on | off
Toggle passive mode.
If passive mode is turned on (default is on),
.Nm
will send a
.Dv EPSV
command for all data connections instead of the usual
.Dv EPRT
command.
The
.Dv EPSV
command requests that the remote server open a port for the data connection
and return the address of that port.
The remote server listens on that port and the client connects to it.
When using the more traditional
.Dv EPRT
command, the client listens on a port and sends that address to the remote
server, who connects back to it.
Passive mode is useful when using
.Nm
through a gateway router or host that controls the directionality of
traffic.
.It Ic lcd Op Ar local-directory
Change the working directory on the local machine.
If
no
.Ar local-directory
is specified, the user's home directory is used.
.It Ic lpwd
Print the working directory on the local machine.
.It Ic put Ar local-file Op Ar remote-file
Store a local file on the remote machine.
If
.Ar remote-file
is left unspecified, the local file name is used.
.It Ic mget Ar remote-files
Do a
.Ic get
for each file name specified.
.It Ic mput Ar local-files
Do a
.Ic put
for each file name specified.
.El
.Sh AUTO-FETCHING FILES
In addition to standard commands, this version of
.Nm
supports an auto-fetch feature.
To enable auto-fetch, simply pass the list of hostnames/files
on the command line.
.Pp
The following formats are valid syntax for an auto-fetch element:
.Bl -tag -width Ds
.Sm off
.It Xo ftp://
.Ar host Op : Ar port
.No / Ar file
.Xc
.Sm on
An FTP URL, retrieved using the FTP protocol if
.Ev ftp_proxy
isn't defined.
Otherwise, transfer using HTTP via the proxy defined in
.Ev ftp_proxy .
.Sm off
.It Xo http://
.Ar host Op : Ar port
.No / Ar file
.Xc
.Sm on
An HTTP URL, retrieved using the HTTP protocol.
If
.Ev http_proxy
is defined, it is used as a URL to an HTTP proxy server.
.Sm off
.It Xo https://
.Ar host Op : Ar port
.No / Ar file
.Xc
.Sm on
An HTTPS URL, retrieved using the HTTPS protocol.
If
.Ev http_proxy
is defined, this HTTPS proxy server will be used to fetch the
file using the CONNECT method.
.It Pf file: Ar file
.Ar file
is retrieved from a mounted file system.
.El
.Sh ENVIRONMENT
.Nm
utilizes the following environment variables:
.Bl -tag -width Ds
.It Ev ftp_proxy
URL of FTP proxy to use when making FTP URL requests
(if not defined, use the standard FTP protocol).
.It Ev http_proxy
URL of HTTP proxy to use when making HTTP(S) URL requests.
.El
.Sh PORT ALLOCATION
For active mode data connections,
.Nm
will listen to a random high TCP port.
The interval of ports used are configurable using
.Xr sysctl 8
variables
.Va net.inet.ip.porthifirst
and
.Va net.inet.ip.porthilast .
.Sh HISTORY
The
.Nm
command first appeard in
.Bx 4.2 .
A complete rewrite of the
.Nm
command first appeared in
.Ox 6.6 .
.Sh AUTHORS
.An Sunil Nimmagadda Aq Mt sunil@openbsd.org
.Sh CAVEATS
While aborting a data transfer, certain FTP servers violate
the protocol by not responding with a 426 reply first, thereby making
.Nm
wait indefinitely for a correct reply.