xc.nro

支持X/YModem和cis_b+协议的串口通讯程序

.ds ]V version 4.3 JPRadley 11 Sep 1993
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.TH XC 1 "24 Nov 1996" "Linux" "Linux Programmer's Manual"
.SH Name
xc \- communications program 
.SH Syntax
.B xc
.RB [ -l device]
.RB [ -s script\ |
.BR -t ] 
.RB [ -w\ ]
.RB [ -p\ ]
.SH Description
.B Xc
calls out over a serial port to another computer. It can manage an interactive
session or be called from
.BR cron (8).
It has various means for transferring files between computers, and can be
partially or totally under the control of scripts.

.B Xc
starts up by reading the file 
.IR xc.init ,
which is sought for in this order: in "XC_PATH", in the current directory,
in your
.I HOME
directory, or in a default directory defined at compile time
( for Linux /usr/local/lib/xc/xc.init ). This startup
file may contain any of the valid
.I SET
commands described below. 
.B Xc
then displays the current settings, and presents an
.I <XC>
prompt, unless either the \fB-t\fR or \fB-s\fR option was present.
.SS \fIOptions\fR
.TP 9
.BI -l device
Use the specified 
.IR device ,
which need not be the full pathname, e.g. "/dev/cua1" or "cua1" are
equally acceptable.
The line could either be directly connected to another computer, or have a
modem on it. In either case (if a value was defined for DIDO at compile time),
.B xc
attempts to suspend a
.BR getty (M)
process that might be on that line, and then use the
.BR uucp (C)
.I LCK..file
mechanism to lock the line.
.TP
.BI -s script
Execute the specified
.I script
after program startup.
.TP
.B -t
Go directly to terminal mode. The default is to go to command mode on program
startup. This option is incompatible with the 
.B -s
option.
.TP
.B -w
Disables call waiting for duration of each connection.
.TP
.B -p
Use pulse dialing instead of touch tone. 

.SS \fIEnvironment\fR
If the environment contains a variable called "MODEM", then the value
of that variable will be the default device. As with the
.B -l
flag, this need not be the
full pathname. To set such a variable, in the Bourne shell, you might say:
.IP
MODEM=cua1; export MODEM
.P
or, in the C shell,
.IP
setenv MODEM cua1
.P
If the environment contains a variable called "BYEcuax", where "cuax"
stands for the basename of the modem line selected either by the MODEM
variable or by the "-l" command option, then the value of that variable
will be sent to the modem when the program terminates. This is useful
for setting the modem back to some preselected state. Example:
.IP
BYEcua1=ATZ ; export BYEcua1
.P
Whatever string is contained in the "Byexxxxx" variable will be
sent to the modem preceded and followed by a carriage-return.

Newer modems can be preset to revert to a predetermined state when the
DTR signal of the computer is dropped, and so would not need to avail
themselves of this feature. Furthermore,
.B getty
programs which have been suspended, and which restart as
.B xc
exits, will reset a modem using dialers or chat scripts referred to in the
/usr/lib/uucp/Devices file.

Note that under Linux the proper device for call-out is a "cua"
device and *NOT* a "tty" device. A "cua" device can point to the
same port as a "tty" device but the kernel handles call-out
devices differently. The "cua" devices use a major number of 5
whereas the "tty" devices use a major number of 4. If you don't
currently have a "cua" device in your /dev directory, you can
make them with these commands:

         mknod /dev/cua0 c 5 64 cua0
         mknod /dev/cua1 c 5 65 cua1
         mknod /dev/cua2 c 5 66 cua2
         etc ...
         etc ...  

The environment may contain a variable called "XC_PATH", consisting
of colon separated absolute paths to directories. If this variable is set to,
say, "/usr/joe/xc:/usr/lib/xc", then those two directories are the
first places searched for any scripts.

.SS \fICommand Mode\fR
When entering characters in command mode (that is, at the 
.I <XC>
prompt), control characters echo as ^x, where "x" is the control character that
was entered. Backspacing (using whatever key is defined in the current
environment) backspaces over both positions of the displayed control character,
as expected. 

An "interpreted" key can be added in a manner similar to that of
.BR vi (C);
simply type ^V followed by the character to insert (backspace, delete,
carriage return, or newline).

The following commands are available at the
.I <XC>
command prompt:

.TS
tab(@);
l1B lw(56) .
c
cis@T{
Respond to an ENQ signal for a CIS B-Plus protocol transfer. This command is
used for both uploading and downloading from CompuServe.
T}

d
dial@T{
Enter the dial directory. Returns to the \fI<XC>\fR
prompt if exited without dialing, but returns to terminal mode after
dialing or running a script.
T}

s \fIfile
script \fIfile\fR@T{
Execute \fIfile\fR, which contains appropriate \fBxc\fR
script commands. Returns to terminal mode when the script is complete.
T}

rx \fIfile\fR@T{
(XMODEM binary receive) Receive \fIfile\fR from the remote system.
Note that packet size and checksum/crc is automatically negotiated
with the sender. Xc will always try to negotiate crc and 1K byte
packet size first. 
T}

rg \fIfile\fR@T{
( 1K XMODEM-G streaming binary receive) Receive \fIfile\fR from the remote
system.  This mode is very fast because the receiver does not 
acknowledge packets which are successfully received.
This protocol should only be used over
extremely clean lines or with error correcting modems. Hardware flow
control should be enabled. Packets are protected with a 16-bit crc.
However, when an error is detected by the receiver the transfer 
is aborted because this protocol does not provide for error recovery.
T}

ry @T{
(YMODEM binary receive) Receive files from the remote system.
This protocol is not invoked with any arguments which makes it
very convenient to use. The YMODEM protocol
automatically receives multiple files preserving file name, size,
date, and permissions.  YMODEM normally uses crc error checking
and 1K packet sizes. If the receiver detects an error in a packet,
it will tell the sender to re-send the packet.
T}

ryg @T{
(YMODEM-G binary streaming receive) Receive files from the remote
system.  This protocol is not invoked with any arguments which makes
it very convenient to use. It is similar to the plain YMODEM protocol,
but correctly received packets are not acknowledged. This provides for
streaming operation and very fast file transfers.  YMODEM-G uses crc
error checking and 1K packet sizes. However, like XMODEM-G, when an
error is detected, the transfer is aborted. There is no attempt at
error recovery. Therefore, this protocol is best used over extremely
clean lines or with error correcting modems. Hardware flow control
should be enabled.  YMODEM-G is as fast, perhaps a bit faster than
ZMODEM.
T}

so \fIfile\fR@( 1K XMODEM binary send)
sx \fIfile\fR@T{
( 128 byte XMODEM binary send) Send \fIfile\fR to the remote system.
Note that for send mode, packet size depends on whether 'so' or 'sx'
is invoked. However, checksum/crc is automatically negotiated
with the remote. Xc will always try to negotiate crc error checking
first. When in 'so' mode, if there are fewer than 896 bytes left
at the end off a file transmission, packet size will automatically
switch to 128 bytes to avoid excessive file size padding. Note that
1K XMODEM protocol is sometimes known as "old YMODEM". 
T}

sg \fIfile\fR@T{
( 1K XMODEM-G streaming binary send) Send \fIfile\fR to the remote
system.  This mode is very fast because it does not wait for packet
acknowledgement from the receiver. Consequently, this protocol should
only be used over extremely clean lines or with error correcting
modems. Hardware flow control should be enabled. Packets are protected
with a 16-bit crc.  But when an error is detected by the receiver the
transfer is aborted because this protocol does not provide for error
recovery.
T}

sy \fIfiles\fR@T{
(YMODEM binary send) Batch send \fIfiles\fR to the remote system.
YMODEM allows multiple files to be specifed on the command line
which makes it very convenient to use. The YMODEM protocol
automatically sends multiple files preserving file name, size,
date, and permissions. YMODEM normally uses crc error checking
and 1K packet sizes.
T}

syg \fIfiles\fR@T{
(YMODEM-G binary send) Streaming protocol, batch send \fIfiles\fR to the
remote system.  YMODEM-G is similar to plain YMODEM with the exception
that YMODEM-G does not wait for acknowledgement before sending the
next packet.  This streaming technique allows for very fast file
transfers. The YMODEM-G protocol automatically sends multiple files
preserving file name, size, date, and permissions. YMODEM-G uses crc
error checking and 1K packet sizes.  Note that with the YMODEM-G
protocol when the receiver detects an error it will abort the
transfer. Therefore YMODEM-G is best used over extermely clean lines
or with error correcting modems. Hardware flow control should be
enabled.
T}

rt \fIfile\fR@(obsolete XMODEM receive mode)
st \fIfile\fR@T{
(obsolete XMODEM send mode) receive/transmit "text" \fIfile\fR from/to
the remote system.  This mode is rarely used nowadays and should
be avoided. Unix systems generally make no distinction between
"binary" and "text" files. Use 'rx' or 'so' or 'sx' instead.
Historically, this mode was primarily used on early CP/M systems.
T}

set \fR[\fIoptions\fR]@T{
Display or set the transmission parameters used by \fBxc\fR. See below.
T}

t
term@Enter terminal mode.

x
q
exit
quit@Exit program. Return to invoking program/shell.

h
hangup@Hang-up the modem.

%p \fIlocal\fR_\fIname\fR@T{
[\fIremote_name\fR] Transmit (put) a file to a remote Unix system. This command
uses standard Unix utilities on the other end. \fIRemote_name\fR defaults to
the same pathname as \fIlocal_name\fR if not otherwise specified.
T}

%t \fIremote\fR_\fIname\fR@T{
[\fIlocal_name\fR] Receive (take) a file from a remote Unix system. This
command uses standard Unix utilities on the other end. \fILocal_name\fR
defaults to the same pathname as \fIremote_name\fR if not otherwise specified.
T}

?
help@T{
Displays a brief summary of \fBxc\fR commands, the SET options, and
terminal-escape commands.
T}
.TE
.P
[Note: a compile-time option can disable the following three options to
prevent any access to shells or other programs outside of
.BR xc .]

.TS
tab(@);
l6B lw(56) .
! \fIcommand\fR@T{
Execute the specified \fIcommand\fR as a child process. If \fIcommand\fR is
omitted, execute a local interactive shell.
(A space is required between the \fB!\fR and the \fIcommand\fR.)
T}

!!@Re-execute the last shell command string. 

$ \fIcommand\fR@T{
Execute a shell \fIcommand\fR with stdin and stdout redi\%rected to the
modem port. This effectively puts the computer into a "host" mode.
(A space is required between the \fB$\fR and the \fIcommand\fR.)
Note: this is usually used when invoking external protocols such as
rz/sz ZMODEM from the command line (i.e. "$ sz foobar.tar.gz").
T}
.TE
.SS \fIUsing the SET Command\fR
The
.I SET
command is used to display and set/reset
.BR xc 's
tunable parameters. Any of these commands may be placed in the
.I .xc
file which is read upon starting up
.BR xc .

Used alone,
.I SET
displays
.BR xc 's
current parameters.

The following parameters can be set (note that except in the case of
.IR name s,
these commands are case-\fIin\fRsensitive, and that there alternative forms
of the commands shown on the XC help screen):

.TS
tab(@) ;
l1 lw(54) .
set auto on|off@T{
Sets the auto-capture feature. When entering terminal mode, capturing
commences without the necessity to manually request it.
T}

set bps \fIvalue\fR
set baud \fIvalue\fR@T{
Set the desired bits/second rate. Supported bps rates are 300, 1200, 2400,
9600 (and, if included at compile time, 19200 and 38400).
T}

set cfile \fIname\fR@Set the \fIname\fR of the capture file.

set cis on|off@T{
Set response to a CompuServe file transfer request (<ENQ>). An "on" value
specifies that when in terminal mode, an <ENQ> character will launch a CIS
B-Plus protocol transfer. This parameter should be set "off" when not
connecting to CompuServe, as phone line noise may cause a bogus file transfer
request.
T}

set cr on|off@T{
In uploads using B-Plus protocol, setting this option "on" will insert a
carriage-return after each newline in an ASCII file. If you expect your ASCII
upload to be captured by DOS users, it is best to set cr "on". If your ASCII
upload is meant strictly for Unix users, then you may set cr "off".
The B-Plus protocol implementation used by \fBxc\fR
will always strip end-of-line carriage-returns from incoming ASCII files.
T}

set dir \fIname\fR@Set the current working directory.

set hdplx on|off@T{
Sets the half-duplex flag. If this flag is set, then all characters typed at
the keyboard while in terminal mode will be echoed to the screen as well as
sent to the modem line. Useful for remote systems that don't echo characters.
T}

set menu on|off@T{
By default, a one-line menu is displayed above the \fI<XC>\fR prompt to
remind the user of options most frequently chosen at this point:
"[d]ial directory [t]erminal mode [q]uit [s]cript [?]help".
Setting the option "off" turns off this display.
T}

set nl on|off@T{
If this option is set "on", then newlines are sent as
carriage-returns. If this option is set "off", then newlines are sent as
newlines (carriage-returns are in any case always sent as carriage-returns).
This option applies to input from the keyboard, or from a disk file using the
"\fBXCAPE\fR \fBF\fR" facility or a script "type" command (See below).
This option has no effect on built-in XMODEM or B-Plus protocol transmissions,
and has no effect on incoming data.
T}

set pfile \fIname\fR@Set the \fIname\fR of the phone directory.

set proto \fIvalue\fR@T{
This refers to the serial port character protocol, not to a file transfer
protocol. The possible values are 8N1, 7E2, or 7O2, (case insensitive) which