term% cat index.txt CU(1) General Commands Manual CU(1)
NAME
cu - call Unix
SYNOPSIS
cu [ -tn ] telno [ service-class ]
DESCRIPTION
Cu places a data call to a given telephone number and expects a com‐
puter to answer. It manages an interactive conversation with possible
transfers of text files. Telno is the telephone number, consisting of
digits with minus signs at appropriate places to indicate delay for
second or subsequent dial tones. A telephone number may also be ex‐
pressed symbolically. The files $HOME/lib/cunumber and /usr/lib/cunum‐
ber are searched for lines with up to four fields separated by white
space:
symbolic telephone number
actual telephone number
service class (see below)
comment
If a comment is present, it is printed out when the connection is made.
The flag argument -n causes cu merely to print out the the number that
would be called, then exit.
The flag argument -t causes cu to use the DC1/DC3 (^S/^Q) protocol to
stop transmission from the remote system when the local terminal buf‐
fers are almost full. This argument should only be used if the remote
system understands that protocol.
An optional second command argument specifies a class of service. Lo‐
cally, one may choose between the 103-type (slow speed) or 112-type
(high-speed) datasets, and perhaps between the Centrex or the data Di‐
mension networks. D or D1200 (or just 1200) is 1200 baud on the Dimen‐
sion system (the default); D300 is 300 baud Dimension. Systems with
their own diallers may allow C1200 and C300 as well, for 1200 and 300
baud Centrex calls.
An explicit service class on the command line overrides any specified
in a cunumber file.
After making the connection, cu runs as two processes: the send process
reads the standard input and passes most of it to the remote system;
the receive process reads from the remote system and passes most data
to the standard output. Lines beginning with `~' have special mean‐
ings.
The send process interprets the following:
~. terminate the conversation.
~EOT terminate the conversation
~<file send the contents of file to the remote system, as
though typed at the terminal.
~! invoke an interactive shell on the local system.
~!cmd ... run the command on the local system (via sh -c).
~$cmd ... run the command locally and send its output to the
remote system.
~b
~%break are identical, and cause a break (300 ms. space) to
be sent.
~%take from [to] copy file `from' (on the remote system) to file `to'
on the local system. If `to' is omitted, the `from'
name is used both places.
~%put from [to] copy file `from' (on local system) to file `to' on
remote system. If `to' is omitted, the `from' name
is used both places.
~~... send the line `~...'.
The receive process handles output diversions of the following form:
~>[>][:]file
zero or more lines to be written to file
~>
Output is diverted (or appended, if `>>' used) to the file. If `:' is
used, the diversion is silent, i.e., it is written only to the file.
If `:' is omitted, output is written both to the file and to the stan‐
dard output. The trailing `~>' terminates the diversion.
The receive process also recognizes lines of the form
~!command
or
~:!command
which cause command to be executed locally. If the `:' is present the
line is not printed before execution.
The use of ~%put requires stty and cat on the remote side. It also re‐
quires that the current erase and kill characters on the remote system
be identical to the current ones on the local system. Backslashes are
inserted at appropriate places.
The use of ~%take requires the existence of echo and tee on the remote
system. Also, stty tabs mode is required on the remote system if tabs
are to be copied without expansion.
FILES
/usr/lib/cunumber, $HOME/lib/cunumber
SEE ALSO
dn(4), ttyld(4), dialout(3)
DIAGNOSTICS
Exit code is zero for normal exit, nonzero (various values) otherwise.
BUGS
The syntax is unique. The speed option (-s) should be put back (it is
at least partially independent of the class of service).
~! is a friend to the malicious.
CU(1)