Hi all, Now that the new version (1.2.4-1) of lpr works properly I have been trying to configure the printing commands of programs that can print directly, such as dvips, ghostview or xfig. I have found that this task is not trivial because in general the files to be printed need to be preprocessed; for example in my case they need to be converted from postscript to deskjet. Not even the printing of a text file is trivial.
In order to facilitate this task I have modified lpr including a couple
of additional options. I am proposing to include these chages in the
new versions of lpr. Follows a description of the modifications. The
modified files are attached.
1- In my experience most of the time the CR/LF translation is not needed,
so it was flipped the way the raw option works. No option: raw printing,
-l option: LF -> CR-LF preprocessing.
2- The -f option was included. It indicates that a FORMFEED character
is appended to the file. In most printers (working in line printer mode)
this would produce the ejection of the last page of the document.
3- The " -F nameoffilter" to give the name of a filter (or pipe),
to be applied to the input file before sending it to the printer. So
lpr -l -Ffilter -Pprinter file
would be equivalent to
filter < file | lpr -l -Pprinter .
Follows a description of how to print different kinds of files on different
kinds of hardware if lpr had the features I am proposing.
--- Printing of text files with line-printers.
In a Cygwin environment one has at least three kinds of text files: Unix
text
files, Windows text files and DOS text files. Unix and Windows text files
usually use some iso-8859-* character set, while DOS uses an ibm-cp*
character
set. On the other hand Windows and DOS text files use CR-LF line
terminations,
while Unix files use LF line terminations. Most printers have a line-printer
mode in which they print each byte of a text file. In many cases, such as in
mine, the printer is DOS-compatible, what that means is that it uses an
ibm-cp*
character set, depending on the language you use, and of course it requires
a
CR-LF or LF-CR line termination.
In my case the printer and DOS use ibm-cp850, while cygwin and Windows use
iso-8859-1. In order to print a text file one has to:
for a DOS text file:
append FF, send raw to lpr;
for a Windows text file:
translate iso-8859-1 to ibm-cp850, append FF, send raw to lpr;
for a Unix text file:
translate iso-8859-1 to ibm-cp850, LF->CR-LF, append FF, send raw to lpr.
If lpr had the options I proposed (including the change of -l) and an
iso2ibm
filter were available the commands for printing text files were:
lpr -f -Pprinter DOS.txt
lpr -f -Fiso2ibm -Pprinter WINDOWS.txt
lpr -f -Fiso2ibm -l -Pprinter UNIX.txt
Right now I have to use scripts in order to accomplish the same tasks.
There are line-printers that use the iso-8859-* character set, in that case
WINDOWS and UNIX text files don't need to be preprocessed, but DOS file
would require an ibm2iso filter:
lpr -f -Fibm2iso -Pprinter DOS.txt
lpr -f -Pprinter WINDOWS.txt
lpr -f -l -Pprinter UNIX.txt
--- Using a postscript printer.
To print a postscript file would be trivial
lpr -Pprinter file.ps
To print a text file you need a formatting filter, that produces a
postscript
file from the text file. Call it txt2ps. txt2ps can be designed to process
both WINDOWS and UNIX files.
lpr -Ftxt2ps file.txt
For a DOS.TWX file you would need to previously apply an ibm2iso filter
lpr -Fibm2iso|txt2ps DOS.txt
--- Using other graphic printers.
Most modern printers have a graphic mode of operation, which use their
own graphic language. The printer I have is a HP color deskjet. The
ghostscript which is distributed by cygwin translate a postscript file
to any kind of other graphic languages. Using gs one can make a shell
script that behaves as a filter from pstscript to deskjet: ps2cdj.
Some examples of printing.
In order to print the output of a program like Word with the option "print
to file" one only needs to send the file raw to the printer
lpr -Pprinter file.cdj
For printing a postscript file
lpr -Fps2cdj -Pprinter file.ps
For printing a text file in graphic mode
lpr -Ftxt2ps|ps2cdj -Pprinter file.txt
lpr -Fibm2iso|txt2ps|ps2cdj -Pprinter DOS.txt
----------------------------------------------------------------------------
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Rodrigo Medina.
Printer.hh
Description: Printer.hh
Printer.cc
Description: Printer.cc
lpr.cc
Description: lpr.cc
lpr.1
Description: lpr.1
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