.TH POSTIO 8
.CT 1 sa_auto
.SH NAME
postio \- serial interface for postscript printers
.SH SYNOPSIS
.B /usr/bin/postscript/postio
[
.I option ...
] [
.I file ...
]
.SH DESCRIPTION
.I Postio
sends
.I files
to a PostScript printer.
It is usually called by the innards of
.IR lp (1).
If no files are named,
the standard input is sent.
.PP
Mandatory argument
.B -l
names the printer.
If
the first character of
.I line
is
.LR / ,
it is assumed to be a local filename like
.LR /dev/tty37 .
Otherwise it is taken to be a network address,
with default network
.LR dk ,
to which the printer is connected.
.PP
These options are probably the most useful:
.nr xx \w'\fL-b\ \fIspeed\ 'u
.TP \n(xxu
.BI \-b speed
Transmit data 
at baud rate
.I speed,
one of 1200, 2400, 4800, 9600 (default), and 19200.
.TP
.B \-q
Disable status queries while
.I files
are being sent to the printer.
When status queries are disabled a dummy message is appended
to the log file before each block is transmitted.
.TP
.BI \-B num
Set the internal buffer size for reading and writing
.I files
to
.I num
bytes, 2048 by default.
.TP
.B \-D
Debug mode:
copy everything read from the printer
to the log file
or standard error.
.TP
.BI \-L file
Log data read from the printer in
.IR file .
Standard error is the default.
Normally only messages indicating a change in the printer's state are logged.
.TP
.BI \-P string
Send
.I string
to the printer before any input
.IR files .
The default
is PostScript code that disables timeouts.
.TP
.BI \-R num
If
.I num
is
.LR 1 ,
run as a single process;
if
.LR 2 ,
use separate processes for reading and writing.
.PP
These options are not useful to spoolers like
.IR lp .
.TP \n(xxu
.B \-i
Interactive mode:
send the
.I files
to the printer,
then copy standard input to the printer
and printer output to standard error.
Overrides many other options.
To have a friendly chat with the printer,
begin by typing
.L executive
on a line by itself.
.TP
.B \-t
Copy printer output that doesn't look like
status information to the standard output;
intended for use with PostScript programs that write results.
.PP
This option should be used only as a last resort:
.TP \n(xxu
.B \-S
Take special measures to send data slowly.
Limits the internal buffer to 1024 bytes,
implies
.B -R1
and disables
.BR -q 
and
.BR -i .
Expensive in CPU time.
.PP
When
.I postio
starts,
it attempts to force the printer into IDLE state
by sending a sequence of
.RB control- t
(status query),
.RB control- c
(interrupt),
and
.RB control- d
(end of job)
characters.
When the printer is idle,
the files are transmitted
with an occasional
.RB control- t
interspersed
(except under
.BR -q ).
After all data have been sent,
.I postio
waits until the printer appears to have finished
before exiting.
Fatal error messages from the printer
cause
.I postio
to exit prematurely.
.SH EXAMPLES
.TP
.L
postio -l/dev/tty01 file1 file2
Runing as a single process at 9600 baud, send file1 and file2
to printer
.LR /dev/tty01 .
.TP
.L
postio -R2 -B4096 -l/dev/tty01 -Llog file1 file2
Similarly,
but use two processes
and a 4096-byte buffer,
and copy printer messages to file
.BR log .
.TP
.L
postio -t -l/dev/tty22 -Llog program >results
Send the PostScript
.L program 
to printer
.BR /dev/tty22 ,
place any data in
.BR results ,
put error messages in
.BR log .
.TP
.L
postio -i -l/cs/dk!my/printer
Connect interactively to the printer at network address
.BR /cs/dk!my/printer .
.SH SEE ALSO
.IR lp (1),
.IR postscript (8)
.SH DIAGNOSTICS
Exit status 1 means a system error
(e.g. can't open the printer),
2 means a PostScript error,
3 means both.
Status 2 is usually caused by a syntax error in an input file.
.SH BUGS 
Multiple
files
with PostScript end-of-job marks
are not guaranteed to work.
.PP
If a network is involved, 
.B \-b
may be ineffective and attempts by
.I postio
to flow-control data in both directions may not work.
Option
.B \-q
can help if the printer is connected to Radian Datakit.