piping to lp is broken after perl upgrade

myuserid7 has asked for the wisdom of the Perl Monks concerning the following question:

I recently moved to CSW blastwave repositories - including perl.

I have a perl script that accepts a C program and does a pretty print to a network printer using lp().

The postscript is capture in a HERE doc.

$prolog = << ENDPROLOG;
.
.
.
A bunch of postscript.
.
.
.
ENDPROLOG

$PRINT_CMD = '/usr/bin/lp';
$outcmd = "| $PRINT_CMD";

open(OUT,$outcmd);

print OUT $prolog;
[download]

After upgrading perl the script is no longer printing the postscript but is printing the postscript code.

I was wondering if someone could point me to a better way.

Comment on piping to lp is broken after perl upgrade Download Code

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Re: piping to lp is broken after perl upgrade by moritz (Cardinal) on Oct 12, 2009 at 22:29 UTC
You should check if open was successful, and also if close was: `open my $output, '\|-', $PRINT_CMD or die "Can't open pipe to $PRINT_CMD: $!"; print $output $prolog; ... close $output or warn "Error while closing pipe to $PRINT_CMD: $!";` [download] Maybe that'll give you some clue about what's wrong. Perl 6 - links to (nearly) everything that is Perl 6.	[reply] [d/l]
Re^2: piping to lp is broken after perl upgrade by myuserid7 (Scribe) on Oct 12, 2009 at 23:26 UTC
I got excited when I saw your close - I thought for sure the open handle was causing the grief. Added the error checking. Nothing. Something is foobar here and I am not sure it is perl. Even from the command line... `cat foo.ps \| /usr/bin/lp -o nobanner` [download] prints the postscript code while... `/usr/bin/lp -o nobanner foo.ps` [download] Prints the postscript document. So I really can't expect my perl script to work as written.	[reply] [d/l] [select]
Re: piping to lp is broken after perl upgrade by GrandFather (Saint) on Oct 13, 2009 at 00:34 UTC
I don't see an issue in the code you've shown except that you're not using strictures (use strict; use warnings;). It wouldn't surprise me a great deal to find that there is something that was waiting in your heredoc to bite and has now bitten. It may help if you: `my $prolog = << 'ENDPROLOG';` [download] so interpolation doesn't happen. True laziness is hard work	[reply] [d/l]
Re^2: piping to lp is broken after perl upgrade by myuserid7 (Scribe) on Oct 14, 2009 at 20:51 UTC
Thanks for your reply. I created a files called test.ps. `$ cat test.ps %!PS /Courier findfont 20 scalefont setfont 72 500 moveto (Hello world!) show showpage` [download] If I send it to the printer, it works. I get a Hello World. So here is a recreation of the script that is failing. `#!/opt/csw/bin/perl -w use strict; use warnings; my $prolog = <<ENDPROLOG; %!PS /Courier findfont 20 scalefont setfont 72 500 moveto (Hello world!) show showpage ENDPROLOG my $PRINT_CMD = '/usr/bin/lp -o nobanner'; open my $output, '\|-', $PRINT_CMD or die "Can't open pipe to $PRINT_CMD: $!"; print $output $prolog; close $output or warn "Error while closing pipe to $PRINT_CMD: $!";` [download]	[reply] [d/l] [select]
Re^3: piping to lp is broken after perl upgrade by myuserid7 (Scribe) on Oct 15, 2009 at 22:15 UTC
I ended up abandoning the use the csw perl for this script. Instead, I pulled the 5.8.9 source and complied it on my Solaris 10 machine using gcc4. I pointed the test script at the new compile and it started working. Sadly, I am not that confident in the blastwave perl now. Surely just paranoia but once bitten...	[reply]


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