ftp.texi

压缩包中包含LINUX下多个命令的源码

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.

@item 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 autologin
option is on (default), ftp will also attempt to automatically log
the user in to the FTP server (see below).

@item passive
Toggle passive mode.  If passive mode is turned on (default
is off), the ftp client will send a PASV command for all data
connections instead of the usual PORT command.  The PASV com-
mand 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 PORT 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
ftp through a gateway router or host that controls the directionality
of traffic.  (Note that though ftp servers are required to support
the PASV command by RFC 1123, some do not.)

@item 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.

@item 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.

@item 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.

@item pwd
Print the name of the current working directory on the remote machine.

@item quit
A synonym for bye.

@item quote arg1 arg2 ...
The arguments specified are sent, verbatim, to the remote FTP server.

@item recv remote-file [local-file]
A synonym for get.

@item 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.

@item remotehelp [command-name]
Request help from the remote FTP server.  If a command-name
is specified it is supplied to the server as well.

@item remotestatus [file-name]
With no arguments, show status of remote machine.  If filename is
specified, show status of file-name on remote machine.

@item rename [from] [to]
Rename the file from on the remote machine, to the file to.

@item 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.

@item 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.

@item rmdir directory-name
Delete a directory on the remote machine.

@item 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.

@item send local-file [remote-file]
A synonym for put.

@item 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.

@item site arg1 arg2 ...
The arguments specified are sent, verbatim, to the remote FTP
server as a SITE command.

@item size file-name
Return size of file-name on remote machine.

@item status
Show the current status of ftp.

@item struct [struct-name]
Set the file transfer structure to struct-name. By default
``stream'' structure is used.

@item 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.

@item system
Show the type of operating system running on the remote machine.

@item tenex
Set the file transfer type to that needed to talk to TENEX machines.

@item trace
Toggle packet tracing.

@item 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 net- work ASCII.

@item umask [newmask]
Set the default umask on the remote server to newmask. If
newmask is omitted, the current umask is printed.

@item 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.

@item 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.

@item ? [command]
A synonym for help.

@end table

Command arguments which have embedded spaces may be quoted with quote `"'
marks.

@section 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.

@section File Naming Conventions

Files specified as arguments to ftp commands are processed according to
the following rules.

@enumerate

@item
If the file name `-' is specified, the stdin (for reading) or stdout
(for writing) is used.

@item
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''.

@item
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.

@item
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.

@item
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.

@end enumerate

@section 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, form, and struct.

@section The @file{.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:

@table @samp

@item machine name
Identify a remote machine name. The auto-login process searches
the .netrc file for a machine token that matches the remote ma-
chine 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 an-
other machine or a default token is encountered.

@item 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:
@example
           default login anonymous password user@@site
@end example

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.

@item 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.

@item 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
@file{.netrc} is readable by anyone besides the user.

@item 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.

@item 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.

@end table

Ftp utilizes the following environment variables.

@table @samp

@item HOME
For default location of a .netrc file, if one exists.

@item SHELL
For default shell.

@end table

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.