498 lines
17 KiB
Groff
498 lines
17 KiB
Groff
.\" -*- nroff -*-
|
|
.\" manual page [] for chat 1.8
|
|
.\" $Id: chat.8,v 1.11 1998/06/03 04:21:36 jkoshy Exp $
|
|
.\" SH section heading
|
|
.\" SS subsection heading
|
|
.\" LP paragraph
|
|
.\" IP indented paragraph
|
|
.\" TP hanging label
|
|
.TH CHAT 8 "27 Sep 1997" "Chat Version 1.17"
|
|
.SH NAME
|
|
chat \- Automated conversational script with a modem
|
|
.SH SYNOPSIS
|
|
.B chat
|
|
[
|
|
.I options
|
|
]
|
|
.I script
|
|
.SH DESCRIPTION
|
|
.LP
|
|
The \fIchat\fR program defines a conversational exchange between the
|
|
computer and the modem. Its primary purpose is to establish the
|
|
connection between the Point-to-Point Protocol Daemon (\fIpppd\fR) and
|
|
the remote's \fIpppd\fR process.
|
|
.SH OPTIONS
|
|
.TP
|
|
.B -f \fI<chat file>
|
|
Read the chat script from the chat \fIfile\fR. The use of this option
|
|
is mutually exclusive with the chat script parameters. The user must
|
|
have read access to the file. Multiple lines are permitted in the
|
|
file. Space or horizontal tab characters should be used to separate
|
|
the strings.
|
|
.TP
|
|
.B -t \fI<timeout>
|
|
Set the timeout for the expected string to be received. If the string
|
|
is not received within the time limit then the reply string is not
|
|
sent. An alternate reply may be sent or the script will fail if there
|
|
is no alternate reply string. A failed script will cause the
|
|
\fIchat\fR program to terminate with a non-zero error code.
|
|
.TP
|
|
.B -r \fI<report file>
|
|
Set the file for output of the report strings. If you use the keyword
|
|
\fIREPORT\fR, the resulting strings are written to this file. If this
|
|
option is not used and you still use \fIREPORT\fR keywords, the
|
|
\fIstderr\fR file is used for the report strings.
|
|
.TP
|
|
.B -e
|
|
Start with the echo option turned on. Echoing may also be turned on
|
|
or off at specific points in the chat script by using the \fIECHO\fR
|
|
keyword. When echoing is enabled, all output from the modem is echoed
|
|
to \fIstderr\fR.
|
|
.TP
|
|
.B -v
|
|
Request that the \fIchat\fR script be executed in a verbose mode. The
|
|
\fIchat\fR program will then log the execution state of the chat
|
|
script as well as all text received from the modem and the output
|
|
strings sent to the modem. The default is to log through
|
|
.IR syslog (3);
|
|
the logging method may be altered with the -S and -s flags.
|
|
Logging is
|
|
done to the \fIlocal2\fR facility at level \fIinfo\fR for verbose tracing
|
|
and level \fIerr\fR for some errors.
|
|
.TP
|
|
.B -V
|
|
Request that the \fIchat\fR script be executed in a stderr verbose
|
|
mode. The \fIchat\fR program will then log all text received from the
|
|
modem and the output strings sent to the modem to the stderr device. This
|
|
device is usually the local console at the station running the chat or
|
|
pppd program.
|
|
.TP
|
|
.B -s
|
|
Use stderr. All log messages from '-v' and all error messages will be
|
|
sent to stderr.
|
|
.TP
|
|
.B -S
|
|
Do not use
|
|
.IR syslog (3).
|
|
By default, error messages are sent to
|
|
.IR syslog (3).
|
|
The use of -S will prevent both log messages from '-v' and
|
|
error messages from being sent to
|
|
.IR syslog (3).
|
|
.TP
|
|
.B -T \fI<phone number>
|
|
Pass in an arbitrary string, usually a phone number, that will be
|
|
substituted for the \\T substitution metacharacter in a send string.
|
|
.TP
|
|
.B -U \fI<phone number 2>
|
|
Pass in a second string, usually a phone number, that will be
|
|
substituted for the \\U substitution metacharacter in a send string.
|
|
This is useful when dialing an ISDN terminal adapter that requires two
|
|
numbers.
|
|
.TP
|
|
.B script
|
|
If the script is not specified in a file with the \fI-f\fR option then
|
|
the script is included as parameters to the \fIchat\fR program.
|
|
.SH CHAT SCRIPT
|
|
.LP
|
|
The \fIchat\fR script defines the communications.
|
|
.LP
|
|
A script consists of one or more "expect-send" pairs of strings,
|
|
separated by spaces, with an optional "subexpect-subsend" string pair,
|
|
separated by a dash as in the following example:
|
|
.IP
|
|
ogin:-BREAK-ogin: ppp ssword: hello2u2
|
|
.LP
|
|
This line indicates that the \fIchat\fR program should expect the string
|
|
"ogin:". If it fails to receive a login prompt within the time interval
|
|
allotted, it is to send a break sequence to the remote and then expect the
|
|
string "ogin:". If the first "ogin:" is received then the break sequence is
|
|
not generated.
|
|
.LP
|
|
Once it received the login prompt the \fIchat\fR program will send the
|
|
string ppp and then expect the prompt "ssword:". When it receives the
|
|
prompt for the password, it will send the password hello2u2.
|
|
.LP
|
|
A carriage return is normally sent following the reply string. It is not
|
|
expected in the "expect" string unless it is specifically requested by using
|
|
the \\r character sequence.
|
|
.LP
|
|
The expect sequence should contain only what is needed to identify the
|
|
string. Since it is normally stored on a disk file, it should not contain
|
|
variable information. It is generally not acceptable to look for time
|
|
strings, network identification strings, or other variable pieces of data as
|
|
an expect string.
|
|
.LP
|
|
To help correct for characters which may be corrupted during the initial
|
|
sequence, look for the string "ogin:" rather than "login:". It is possible
|
|
that the leading "l" character may be received in error and you may never
|
|
find the string even though it was sent by the system. For this reason,
|
|
scripts look for "ogin:" rather than "login:" and "ssword:" rather than
|
|
"password:".
|
|
.LP
|
|
A very simple script might look like this:
|
|
.IP
|
|
ogin: ppp ssword: hello2u2
|
|
.LP
|
|
In other words, expect ....ogin:, send ppp, expect ...ssword:, send hello2u2.
|
|
.LP
|
|
In actual practice, simple scripts are rare. At the vary least, you
|
|
should include sub-expect sequences should the original string not be
|
|
received. For example, consider the following script:
|
|
.IP
|
|
ogin:--ogin: ppp ssword: hello2u2
|
|
.LP
|
|
This would be a better script than the simple one used earlier. This would look
|
|
for the same login: prompt, however, if one was not received, a single
|
|
return sequence is sent and then it will look for login: again. Should line
|
|
noise obscure the first login prompt then sending the empty line will
|
|
usually generate a login prompt again.
|
|
.SH COMMENTS
|
|
Comments can be embedded in the chat script. A comment is a line which
|
|
starts with the \fB#\fR (hash) character in column 1. Such comment
|
|
lines are just ignored by the chat program. If a '#' character is to
|
|
be expected as the first character of the expect sequence, you should
|
|
quote the expect string.
|
|
If you want to wait for a prompt that starts with a # (hash)
|
|
character, you would have to write something like this:
|
|
.IP
|
|
# Now wait for the prompt and send logout string
|
|
.br
|
|
\'# ' logout
|
|
.LP
|
|
|
|
.SH ABORT STRINGS
|
|
Many modems will report the status of the call as a string. These
|
|
strings may be \fBCONNECTED\fR or \fBNO CARRIER\fR or \fBBUSY\fR. It
|
|
is often desirable to terminate the script should the modem fail to
|
|
connect to the remote. The difficulty is that a script would not know
|
|
exactly which modem string it may receive. On one attempt, it may
|
|
receive \fBBUSY\fR while the next time it may receive \fBNO CARRIER\fR.
|
|
.LP
|
|
These "abort" strings may be specified in the script using the \fIABORT\fR
|
|
sequence. It is written in the script as in the following example:
|
|
.IP
|
|
ABORT BUSY ABORT 'NO CARRIER' '' ATZ OK ATDT5551212 CONNECT
|
|
.LP
|
|
This sequence will expect nothing; and then send the string ATZ. The
|
|
expected response to this is the string \fIOK\fR. When it receives \fIOK\fR,
|
|
the string ATDT5551212 to dial the telephone. The expected string is
|
|
\fICONNECT\fR. If the string \fICONNECT\fR is received the remainder of the
|
|
script is executed. However, should the modem find a busy telephone, it will
|
|
send the string \fIBUSY\fR. This will cause the string to match the abort
|
|
character sequence. The script will then fail because it found a match to
|
|
the abort string. If it received the string \fINO CARRIER\fR, it will abort
|
|
for the same reason. Either string may be received. Either string will
|
|
terminate the \fIchat\fR script.
|
|
.SH CLR_ABORT STRINGS
|
|
This sequence allows for clearing previously set \fBABORT\fR strings.
|
|
\fBABORT\fR strings are kept in an array of a pre-determined size (at
|
|
compilation time); \fBCLR_ABORT\fR will reclaim the space for cleared
|
|
entries so that new strings can use that space.
|
|
.SH SAY STRINGS
|
|
The \fBSAY\fR directive allows the script to send strings to the user
|
|
at the terminal via standard error. If \fBchat\fR is being run by
|
|
pppd, and pppd is running as a daemon (detached from its controlling
|
|
terminal), standard error will normally be redirected to the file
|
|
/etc/ppp/connect-errors.
|
|
.LP
|
|
\fBSAY\fR strings must be enclosed in single or double quotes. If
|
|
carriage return and line feed are needed in the string to be output,
|
|
you must explicitly add them to your string.
|
|
.LP
|
|
The SAY strings could be used to give progress messages in sections of
|
|
the script where you want to have 'ECHO OFF' but still let the user
|
|
know what is happening. An example is:
|
|
.IP
|
|
ABORT BUSY
|
|
.br
|
|
ECHO OFF
|
|
.br
|
|
SAY "Dialling your ISP...\\n"
|
|
.br
|
|
\'' ATDT5551212
|
|
.br
|
|
TIMEOUT 120
|
|
.br
|
|
SAY "Waiting up to 2 minutes for connection ... "
|
|
.br
|
|
CONNECT ''
|
|
.br
|
|
SAY "Connected, now logging in ...\n"
|
|
.br
|
|
ogin: account
|
|
.br
|
|
ssword: pass
|
|
.br
|
|
$ \c
|
|
SAY "Logged in OK ...\n"
|
|
\fIetc ...\fR
|
|
.LP
|
|
This sequence will only present the SAY strings to the user and all
|
|
the details of the script will remain hidden. For example, if the
|
|
above script works, the user will see:
|
|
.IP
|
|
Dialling your ISP...
|
|
.br
|
|
Waiting up to 2 minutes for connection ... Connected, now logging in ...
|
|
.br
|
|
Logged in OK ...
|
|
.LP
|
|
|
|
.SH REPORT STRINGS
|
|
A \fBreport\fR string is similar to the ABORT string. The difference
|
|
is that the strings, and all characters to the next control character
|
|
such as a carriage return, are written to the report file.
|
|
.LP
|
|
The report strings may be used to isolate the transmission rate of the
|
|
modem's connect string and return the value to the chat user. The
|
|
analysis of the report string logic occurs in conjunction with the
|
|
other string processing such as looking for the expect string. The use
|
|
of the same string for a report and abort sequence is probably not
|
|
very useful, however, it is possible.
|
|
.LP
|
|
The report strings to no change the completion code of the program.
|
|
.LP
|
|
These "report" strings may be specified in the script using the \fIREPORT\fR
|
|
sequence. It is written in the script as in the following example:
|
|
.IP
|
|
REPORT CONNECT ABORT BUSY '' ATDT5551212 CONNECT '' ogin: account
|
|
.LP
|
|
This sequence will expect nothing; and then send the string
|
|
ATDT5551212 to dial the telephone. The expected string is
|
|
\fICONNECT\fR. If the string \fICONNECT\fR is received the remainder
|
|
of the script is executed. In addition the program will write to the
|
|
expect-file the string "CONNECT" plus any characters which follow it
|
|
such as the connection rate.
|
|
.SH CLR_REPORT STRINGS
|
|
This sequence allows for clearing previously set \fBREPORT\fR strings.
|
|
\fBREPORT\fR strings are kept in an array of a pre-determined size (at
|
|
compilation time); \fBCLR_REPORT\fR will reclaim the space for cleared
|
|
entries so that new strings can use that space.
|
|
.SH ECHO
|
|
The echo options controls whether the output from the modem is echoed
|
|
to \fIstderr\fR. This option may be set with the \fI-e\fR option, but
|
|
it can also be controlled by the \fIECHO\fR keyword. The "expect-send"
|
|
pair \fIECHO\fR \fION\fR enables echoing, and \fIECHO\fR \fIOFF\fR
|
|
disables it. With this keyword you can select which parts of the
|
|
conversation should be visible. For instance, with the following
|
|
script:
|
|
.IP
|
|
ABORT 'BUSY'
|
|
.br
|
|
ABORT 'NO CARRIER'
|
|
.br
|
|
'' ATZ
|
|
.br
|
|
OK\\r\\n ATD1234567
|
|
.br
|
|
\\r\\n \\c
|
|
.br
|
|
ECHO ON
|
|
.br
|
|
CONNECT \\c
|
|
.br
|
|
ogin: account
|
|
.LP
|
|
all output resulting from modem configuration and dialing is not visible,
|
|
but starting with the \fICONNECT\fR (or \fIBUSY\fR) message, everything
|
|
will be echoed.
|
|
.SH HANGUP
|
|
The HANGUP options control whether a modem hangup should be considered
|
|
as an error or not. This option is useful in scripts for dialling
|
|
systems which will hang up and call your system back. The HANGUP
|
|
options can be \fBON\fR or \fBOFF\fR.
|
|
.br
|
|
When HANGUP is set OFF and the modem hangs up (e.g., after the first
|
|
stage of logging in to a callback system), \fBchat\fR will continue
|
|
running the script (e.g., waiting for the incoming call and second
|
|
stage login prompt). As soon as the incoming call is connected, you
|
|
should use the \fBHANGUP ON\fR directive to reinstall normal hang up
|
|
signal behavior. Here is an (simple) example script:
|
|
.IP
|
|
ABORT 'BUSY'
|
|
.br
|
|
'' ATZ
|
|
.br
|
|
OK\\r\\n ATD1234567
|
|
.br
|
|
\\r\\n \\c
|
|
.br
|
|
CONNECT \\c
|
|
.br
|
|
\'Callback login:' call_back_ID
|
|
.br
|
|
HANGUP OFF
|
|
.br
|
|
ABORT "Bad Login"
|
|
.br
|
|
\'Callback Password:' Call_back_password
|
|
.br
|
|
TIMEOUT 120
|
|
.br
|
|
CONNECT \\c
|
|
.br
|
|
HANGUP ON
|
|
.br
|
|
ABORT "NO CARRIER"
|
|
.br
|
|
ogin:--BREAK--ogin: real_account
|
|
.br
|
|
\fIetc ...\fR
|
|
.LP
|
|
.SH TIMEOUT
|
|
The initial timeout value is 45 seconds. This may be changed using the \fB-t\fR
|
|
parameter.
|
|
.LP
|
|
To change the timeout value for the next expect string, the following
|
|
example may be used:
|
|
.IP
|
|
ATZ OK ATDT5551212 CONNECT TIMEOUT 10 ogin:--ogin: TIMEOUT 5 assword: hello2u2
|
|
.LP
|
|
This will change the timeout to 10 seconds when it expects the login:
|
|
prompt. The timeout is then changed to 5 seconds when it looks for the
|
|
password prompt.
|
|
.LP
|
|
The timeout, once changed, remains in effect until it is changed again.
|
|
.SH SENDING EOT
|
|
The special reply string of \fIEOT\fR indicates that the chat program
|
|
should send an EOT character to the remote. This is normally the
|
|
End-of-file character sequence. A return character is not sent
|
|
following the EOT.
|
|
.PR
|
|
The EOT sequence may be embedded into the send string using the
|
|
sequence \fI^D\fR.
|
|
.SH GENERATING BREAK
|
|
The special reply string of \fIBREAK\fR will cause a break condition
|
|
to be sent. The break is a special signal on the transmitter. The
|
|
normal processing on the receiver is to change the transmission rate.
|
|
It may be used to cycle through the available transmission rates on
|
|
the remote until you are able to receive a valid login prompt.
|
|
.PR
|
|
The break sequence may be embedded into the send string using the
|
|
\fI\\K\fR sequence.
|
|
.SH ESCAPE SEQUENCES
|
|
The expect and reply strings may contain escape sequences. All of the
|
|
sequences are legal in the reply string. Many are legal in the expect.
|
|
Those which are not valid in the expect sequence are so indicated.
|
|
.TP
|
|
.B ''
|
|
Expects or sends a null string. If you send a null string then it will still
|
|
send the return character. This sequence may either be a pair of apostrophe
|
|
or quote characters.
|
|
.TP
|
|
.B \\\\b
|
|
represents a backspace character.
|
|
.TP
|
|
.B \\\\c
|
|
Suppresses the newline at the end of the reply string. This is the only
|
|
method to send a string without a trailing return character. It must
|
|
be at the end of the send string. For example,
|
|
the sequence hello\\c will simply send the characters h, e, l, l, o.
|
|
.I (not valid in expect.)
|
|
.TP
|
|
.B \\\\d
|
|
Delay for one second. The program uses sleep(1) which will delay to a
|
|
maximum of one second.
|
|
.I (not valid in expect.)
|
|
.TP
|
|
.B \\\\K
|
|
Insert a BREAK
|
|
.I (not valid in expect.)
|
|
.TP
|
|
.B \\\\n
|
|
Send a newline or linefeed character.
|
|
.TP
|
|
.B \\\\N
|
|
Send a null character. The same sequence may be represented by \\0.
|
|
.I (not valid in expect.)
|
|
.TP
|
|
.B \\\\p
|
|
Pause for a fraction of a second. The delay is 1/10th of a second.
|
|
.I (not valid in expect.)
|
|
.TP
|
|
.B \\\\q
|
|
Suppress writing the string to
|
|
.IR syslogd (8).
|
|
The string ?????? is
|
|
written to the log in its place.
|
|
.I (not valid in expect.)
|
|
.TP
|
|
.B \\\\r
|
|
Send or expect a carriage return.
|
|
.TP
|
|
.B \\\\s
|
|
Represents a space character in the string. This may be used when it
|
|
is not desirable to quote the strings which contains spaces. The
|
|
sequence 'HI TIM' and HI\\sTIM are the same.
|
|
.TP
|
|
.B \\\\t
|
|
Send or expect a tab character.
|
|
.TP
|
|
.B \\\\\\\\
|
|
Send or expect a backslash character.
|
|
.TP
|
|
.B \\\\ddd
|
|
Collapse the octal digits (ddd) into a single ASCII character and send that
|
|
character.
|
|
.I (some characters are not valid in expect.)
|
|
.TP
|
|
.B \^^C
|
|
Substitute the sequence with the control character represented by C.
|
|
For example, the character DC1 (17) is shown as \^^Q.
|
|
.I (some characters are not valid in expect.)
|
|
.SH TERMINATION CODES
|
|
The \fIchat\fR program will terminate with the following completion
|
|
codes.
|
|
.TP
|
|
.B 0
|
|
The normal termination of the program. This indicates that the script
|
|
was executed without error to the normal conclusion.
|
|
.TP
|
|
.B 1
|
|
One or more of the parameters are invalid or an expect string was too
|
|
large for the internal buffers. This indicates that the program as not
|
|
properly executed.
|
|
.TP
|
|
.B 2
|
|
An error occurred during the execution of the program. This may be due
|
|
to a read or write operation failing for some reason or chat receiving
|
|
a signal such as SIGINT.
|
|
.TP
|
|
.B 3
|
|
A timeout event occurred when there was an \fIexpect\fR string without
|
|
having a "-subsend" string. This may mean that you did not program the
|
|
script correctly for the condition or that some unexpected event has
|
|
occurred and the expected string could not be found.
|
|
.TP
|
|
.B 4
|
|
The first string marked as an \fIABORT\fR condition occurred.
|
|
.TP
|
|
.B 5
|
|
The second string marked as an \fIABORT\fR condition occurred.
|
|
.TP
|
|
.B 6
|
|
The third string marked as an \fIABORT\fR condition occurred.
|
|
.TP
|
|
.B 7
|
|
The fourth string marked as an \fIABORT\fR condition occurred.
|
|
.TP
|
|
.B ...
|
|
The other termination codes are also strings marked as an \fIABORT\fR
|
|
condition.
|
|
.LP
|
|
Using the termination code, it is possible to determine which event
|
|
terminated the script. It is possible to decide if the string "BUSY"
|
|
was received from the modem as opposed to "NO DIAL TONE". While the
|
|
first event may be retried, the second will probably have little
|
|
chance of succeeding during a retry.
|
|
.SH SEE ALSO
|
|
Additional information about \fIchat\fR scripts may be found with UUCP
|
|
documentation. The \fIchat\fR script was taken from the ideas proposed
|
|
by the scripts used by the \fIuucico\fR program.
|
|
.LP
|
|
uucico(1), uucp(1), syslog(3), syslogd(8).
|
|
.SH COPYRIGHT
|
|
The \fIchat\fR program is in public domain. This is not the GNU public
|
|
license. If it breaks then you get to keep both pieces.
|