postio(1) User Commands postio(1)
postio - serial interface for PostScript printers
postio -l line [-D] [-i] [-q] [-t] [-S] [-b speed] [-B num]
[-L file] [-P string] [-R num] [file]...
postio sends files to the PostScript printer attached to line. If no files are specified
the standard input is sent.
The first group of options should be sufficient for most applications:
-D Enable debug mode. Guarantees that everything read on line will be added to
the log file (standard error by default).
-q Prevents status queries while files are being sent to the printer. When sta-
tus queries are disabled a dummy message is appended to the log file before
each block is transmitted.
-b speed Transmit data over line at baud rate speed. Recognized baud rates are 1200,
2400, 4800, 9600, and 19200. The default speed is 9600 baud.
-B num Set the internal buffer size for reading and writing files to num bytes. By
default num is 2048 bytes.
-l line Connect to the printer attached to line. In most cases there is no default
and postio must be able to read and write line. If the line does not begin
with a / it may be treated as a Datakit destination.
-L file Data received on line gets put in file. The default log file is standard
error. Printer or status messages that don't show a change in state are not
normally written to file but can be forced out using the -D option.
-P string Send string to the printer before any of the input files. The default string
is simple PostScript code that disables timeouts.
-R num Run postio as a single process if num is 1 or as separate read and write pro-
cesses if num is 2. By default postio runs as a single process.
The next two options are provided for users who expect to run postio on their own. Neither
is suitable for use in spooler interface programs:
-i Run the program in interactive mode. Any files are sent first and followed by the
standard input. Forces separate read and write processes and overrides many other
options. To exit interactive mode use your interrupt or quit character. To get a
friendly interactive connection with the printer type executive on a line by itself.
-t Data received on line and not recognized as printer or status information is written
to the standard output. Forces separate read and write processes. Convenient if you
have a PostScript program that will be returning useful data to the host.
The last option is not generally recommended and should only be used if all else fails to
provide a reliable connection:
-S Slow the transmission of data to the printer. Severely limits throughput, runs as a
single process, disables the -q option, limits the internal buffer size to 1024
bytes, can use an excessive amount of CPU time, and does nothing in interactive
The best performance will usually be obtained by using a large internal buffer (the -B
option) and by running the program as separate read and write processes (the -R 2 option).
Inability to fork the additional process causes postio to continue as a single read/write
process. When one process is used, only data sent to the printer is flow controlled.
The options are not all mutually exclusive. The -i option always wins, selecting its own
settings for whatever is needed to run interactive mode, independent of anything else
found on the command line. Interactive mode runs as separate read and write processes and
few of the other options accomplish anything in the presence of the -i option. The -t
option needs a reliable two way connection to the printer and therefore tries to force
separate read and write processes. The -S option relies on the status query mechanism, so
-q is disabled and the program runs as a single process.
In most cases postio starts by making a connection to line and then attempts to force the
printer into the IDLE state by sending an appropriate sequence of ^T (status query), ^C
(interrupt), and ^D (end of job) characters. When the printer goes IDLE, files are trans-
mitted along with an occasional ^T (unless the -q option was used). After all the files
are sent the program waits until it's reasonably sure the job is complete. Printer gener-
ated error messages received at any time except while establishing the initial connection
(or when running interactive mode) cause postio to exit with a non-zero status. In addi-
tion to being added to the log file, printer error messages are also echoed to standard
Example 1 Examples of the postio command.
Run as a single process at 9600 baud and send file1 and file2 to the printer attached to
example% postio -l /dev/tty01 file1 file2
Same as above except two processes are used, the internal buffer is set to 4096 bytes, and
data returned by the printer gets put in file log:
example% postio -R 2 -B 4096 -l/dev/tty01 -L log file1 file2
Establish an interactive connection with the printer at Datakit destination my/printer:
example% postio -i -l my/printer
Send file program to the printer connected to /dev/tty22, recover any data in file
results, and put log messages in file log:
example% postio -t -l /dev/tty22 -L log program >results
The following exit values are returned:
0 Successful completion.
non-zero An error occurred.
See attributes(5) for descriptions of the following attributes:
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|Availability |SUNWpsf |
download(1), dpost(1), postdaisy(1), postdmd(1), postmd(1), postprint(1), postreverse(1),
The input files are handled as a single PostScript job. Sending several different jobs,
each with their own internal end of job mark (^D) is not guaranteed to work properly. pos-
tio may quit before all the jobs have completed and could be restarted before the last one
All the capabilities described above may not be available on every machine or even across
the different versions of the UNIX system that are currently supported by the program.
There may be no default line, so using the -l option is strongly recommended. If omitted,
postio may attempt to connect to the printer using the standard output. If Datakit is
involved, the -b option may be ineffective and attempts by postio to impose flow control
over data in both directions may not work. The -q option can help if the printer is con-
nected to RADIAN. The -S option is not generally recommended and should be used only if
all other attempts to establish a reliable connection fail.
SunOS 5.11 9 Sep 1996 postio(1)