question on printing to /dev/lp

[Huub]

Hi,

I want to print my output to a printer and not to screen. In the FAQ I
read about filehandles. Do I open printers the same way as files or
differently? And how about ejecting a sheet from the printer? Is there a
command for it?

Thanks,

Huub

 

[Ben Morrow]

I want to print my output to a printer and not to screen. In the FAQ I
read about filehandles. Do I open printers the same way as files or
differently? And how about ejecting a sheet from the printer? Is there a
command for it?

The usual way to print on Unix systems is to open a pipe to lpr(1) or
lp(1) (depending on which you have). Read the manual to find out what
data formats they accept: commonly, you must convert your output to
PostScript. You can do this with the program a2ps (among others); this
will convert a form-feed ("\cL") into a new page.

Ben

 

[Huub]

The usual way to print on Unix systems is to open a pipe to lpr(1) or
lp(1) (depending on which you have). Read the manual to find out what
data formats they accept: commonly, you must convert your output to
PostScript. You can do this with the program a2ps (among others); this
will convert a form-feed ("\cL") into a new page.

Ben

Sorry, but I don't fully understand it. You're mentioning pipe, but when
I read "man perlfunc", it seems there's no way to really print to a
(network)printer from the script. As I understand I have to print to
file first, and then to a printer. Is this correct?

 

[Ben Morrow]

Quoth Huub <"v.niekerk at hccnet.nl">:

[ please attribute quotations ]

Sorry, but I don't fully understand it. You're mentioning pipe, but when
I read "man perlfunc", it seems there's no way to really print to a
(network)printer from the script. As I understand I have to print to
file first, and then to a printer. Is this correct?

No. You have to open a pipe lpr(1) or lp(1). If you don't understand
this statement you need to find out more about how your OS works before
you try programming for it; and, as I said, you need to find out what
data formats your print spooler will accept.

Ben

 

[Huub]

No. You have to open a pipe lpr(1) or lp(1). If you don't understand
this statement you need to find out more about how your OS works before
you try programming for it; and, as I said, you need to find out what
data formats your print spooler will accept.

Ben

I think I got it. You mean e.g. open(OUTPUT,'|/dev/lp0'), where '|' is
the pipe.

 

[Ben Morrow]

<[email protected]>

[ please attribute quotations. next time you'll go in the killfile. ]

I think I got it. You mean e.g. open(OUTPUT,'|/dev/lp0'), where '|' is
the pipe.

No, I don't. I mean e.g.

open my $LPR, '|-', qw/lpr -Pprinter/ or die "can't fork lpr: $!";

but with the appropriate syntax for the lpr(1) or lp(1) on your system.
Please learn how printing works on your system before trying to do it
from Perl. As I said, on most Unixen printing is through one of the
*programs* lpr or lp; but the syntax and accepted formats vary.

Ben

 

[Huub]

No, I don't. I mean e.g.

open my $LPR, '|-', qw/lpr -Pprinter/ or die "can't fork lpr: $!";

but with the appropriate syntax for the lpr(1) or lp(1) on your system.
Please learn how printing works on your system before trying to do it
from Perl. As I said, on most Unixen printing is through one of the
*programs* lpr or lp; but the syntax and accepted formats vary.

Ben

I know how to deal with printing on Linux and BSD. Using apsfilter and
lpr. Just with Perl it's new to me. Thank you.

 

[Sherm Pendley]

I know how to deal with printing on Linux and BSD. Using apsfilter and
lpr. Just with Perl it's new to me. Thank you.

And now for something completely different...

Have you had a look at the various CUPS modules on CPAN?

sherm--

 

[Huub]

And now for something completely different...

Have you had a look at the various CUPS modules on CPAN?

sherm--

Now I have..thank you.

 

[Huub]

No, I don't. I mean e.g.

open my $LPR, '|-', qw/lpr -Pprinter/ or die "can't fork lpr: $!";

Reading CPAN on open & pipes, I still don't quite understand it. I
assume $LPR is the data to be printed, printer is of course the
printerqueue. But where do I put the filename? I suppose I completely
miss the point somewhere.
Thank you for helping out.

 

[David Squire]

Reading CPAN on open & pipes, I still don't quite understand it. I
assume $LPR is the data to be printed

No. $LPR is the filehandle that is bound to the pipe.

, printer is of course the

printerqueue. But where do I put the filename? I suppose I completely
miss the point somewhere.

There is no filename. You have a pipe, not a file. Anything you print to
the filehandle $LPR will be sent via the pipe to the command 'lpr
-Pprinter'.

Consider this command line version:

cat myfile.ps | lpr -Pprinter1

Here the output of the command 'cat myfile.ps' is piped into the input
of the command 'lpr -Pprinter1'.

HTH,

DS

 

[Huub]

No. $LPR is the filehandle that is bound to the pipe.

OK.

There is no filename. You have a pipe, not a file. Anything you print to
the filehandle $LPR will be sent via the pipe to the command 'lpr
-Pprinter'.

Consider this command line version:


Here the output of the command 'cat myfile.ps' is piped into the input
of the command 'lpr -Pprinter1'.

So if I put the open function first, and then this:

print($LPR," Contr. 2007\n");

it should pipe the string to the printer?

 

[David Squire]

So if I put the open function first, and then this:

print($LPR," Contr. 2007\n");

it should pipe the string to the printer?

Close, but you have the syntax for using filehandles with print wrong.
It should be:

print $LPR "Some string";

The comma will break it... this stuff is in the documentation: perldoc
perlfunc

.... and of course, as others have said, you have to send the printer
something it can understand, e.g. postscript.


DS

 

[Huub]

Thank you very much. The print command was something I thought had taken
from CPAN, but now it's working. The printer accepts ASCII, so all is
finally working. Thank you (all) for your patience.