tftp - Provides the Trivial File Transfer Protocol (TFTP)
Interactive form: tftp [remote_host] [port]
Command-line form: tftp remote_host [port] -subcommand
[args]
The tftp command transfers files between hosts using TFTP.
Because TFTP is a minimal file transfer protocol, the tftp
command does not provide all of the features described
under the ftp command. For example, tftp does not provide
subcommands to list remote files or change directories at
the remote host, and limited file access privileges are
given to the remote TFTP server. Note that the tftp command
is not available when your host is operating in controlled
access (secure) mode.
The remote host must have a tftpd server started by its
inetd server and have an account defined that limits the
access of tftpd. Use the tftpd command to set up the TFTP
environment and the nobody account.
The tftp command has two forms: interactive form and command
line form. In the interactive form, tftp is issued
alone or with a host argument that specifies the default
host to use for file transfers during this session. You
can also specify a port for the tftp connection to use.
When you enter the interactive form, the tftp> prompt
appears. In the command line form, you specify command
arguments on the command line, and no prompt appears. The
tftp command can overwrite a file, but prompts you before
doing so.
When transferring data to a remote host, the transferred
data is placed in the directory specified by the
remote_file argument. remote_file must be a fully specified
filename, and the remote file must both exist and
have write permission set for others. The tftp command
attempts to write the data to the specified file. However,
if the remote TFTP server does not have the appropriate
privileges to write the remote file or if the file
does not already exist, the transfer fails.
The tftp subcommands can be entered in either their interactive
form or in their command line form. Displays help
information. If a subcommand is specified, only information
about that subcommand is displayed. Synonym for the
mode ascii subcommand. Synonym for the mode binary subcommand.
This subcommand is used in the interactive mode.
The image mode is the same as mode binary, but is used on
the command line. Sets the data block size in bytes.
Specify a value in the range 8 to 65464. The default block
size is 512 bytes. Packet size is equivalent to the blocksize
+4 bytes (516 bytes by default).
The value of blocksize is constrained by the size
of the UDP socket send buffer. Before setting the
block size to a large value, you should verify the
size of the UDP socket send buffer. This buffer has
a default size of 9216 bytes. You can increase the
buffer size by modifying the value of the
udp_sendspace system configuration parameter. Refer
to the sys_attrs(5) and sys_attrs_inet(5) reference
pages for more information on checking and setting
the udp_sendspace parameter. Sets the remote host,
and optionally the port, for file transfers.
Because the TFTP protocol does not maintain connections
between transfers, the connect subcommand
does not create a connection to host, but stores
the settings for transfer operations. Because the
remote host can be specified as part of the get or
put subcommands, which overrides any host previously
specified, the connect subcommand is not
required. Transfers a file or set of files from
the remote host to the local host. Each of the
remote_file arguments can be specified in one of
the following two ways: As a file that exists on
the remote host, if a default host was already
specified. As host:file, where host is the remote
host and file is the name of the file to copy to
the local system. If this form of the argument is
used, the host specified for the last transfer
becomes the default host for subsequent transfers
in this tftp session.
In either case, remote_file must be a fully-specified
filename. Toggles hash marks. Sets the
transfer mode to ascii or binary. A transfer mode
of ascii is the default. Sets mode to octet.
Transfers a file or set of files from the local
host onto the remote host. The remote_directory
and remote_file arguments can be specified in one
of the following two ways: As a file or directory
that exists on the remote host, if a default host
was already specified. As host:remote_file, where
host is the remote host and remote_file is the name
of the file or directory on the remote system. If
this form of the argument is used, the host specified
for the last transfer becomes the default host
for subsequent transfers in this tftp session.
In either of these cases, the remote filename or
directory name must be a full pathname, even if the
local and remote directories have the same name. If
a remote directory is specified, the remote host is
assumed to use UNIX pathname syntax. Exits tftp.
An End-of-File also exits the program. Displays
transfer rate information. Defines the retransmission
time-out for each packet, in seconds. Shows
the current status of tftp, including the current
transfer mode (ascii or binary), connection status,
time-out value, and so on. Sets the total transmission
time-out to the number of seconds specified
by value. Turns packet tracing on or off. Turns
verbose mode, which displays additional information
during file transfer, on or off.
To enter tftp, check the current status, connect to host1,
and transfer the file update from host1 to the local host,
enter: $ tftp tftp> status
Not connected. Mode: netascii Verbose: off Tracing: off
Rexmt_interval: 5 seconds, Max-timeout: 25 seconds
tftp> connect host1 tftp> get /u/alice/update update tftp>
quit $
The get subcommand transfers the file update from
the remote host to your local host. Note that the
directory /u/alice on the remote host must have
read permission set for others.
To perform the same operation in command-line mode,
enter: $ tftp host1 -status -get /u/alice/update
update Connected to host1. Mode: netascii Verbose:
off Tracing: off Rexmt_interval: 5 seconds, Maxtimeout:
25 seconds
To open a tftp connection to host1, set binary
mode, transfer the file game.exe from the local
host to host1, and rename the file in the process,
enter: $ tftp host1 tftp> binary tftp> put game.exe
/u/alice/tictactoe.exe
The put subcommand transfers the file game.exe from
your local host to the remote host as tictactoe.exe.
Note that the directory /u/alice on the
remote host must have write permission set for others.
Also, the file tictactoe.exe must already
exist on the server and have write permission set
for others.
To perform the same operation in command-line mode,
enter: $ tftp host1 -binary -put game.exe
/u/alice/tictactoe.exe
To transfer two files from the local host to two
remote hosts, enter: $ tftp tftp> put product.html
pricelist.html host1:/u/alice/public_html tftp> put
product.html pricelist.html host2:/public/documents
The put subcommand transfers the files from your
local host to the specified directory on each
remote host. Again, the files and directories must
already exist on the remote hosts and have write
permissions set for others. When the file transfer
is complete, the last host, host2, becomes the
default host for subsequent transfers in this tftp
session.
To perform the same operation in command-line mode,
enter: $ tftp host1 -put product.html
pricelist.html /u/alice/public_html $ tftp host2
-put product.html pricelist.html /public/documents
Defines the address of the local host, and specifies the
names and addresses of remote hosts. Defines the sockets
and protocols used for Internet services.
Commands: ftp(1), ftpd(8), inetd(8), rcp(1), syslogd(8),
tftpd(8)
tftp(1)
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