If you use binmode on your input and output filehandles, you should be able to do a "non-edit" of your file, loading and saving it unmodified, and it should still work.

I'm not sure, but I think I remember that PCL is not all that trivial to generate and edit, so depending on your task, simple string replacements may or may not work. But that depends on the kind of replacements you do.

Yes, binmode does help me in reading the characters as they are. But I'm not sure as to how many bytes I should read at a time. Since PCL files are not regular ASCII files and they are not delimited on "\n", reading them one line at a time is not a simple thing unless I know the line delimiter.

I've been trying to find the line and page delimiter from those characters in the file and using PCL command reference, but I couldn't succeed.

I figured all the commands begin with ESC control code.

GoForIt:

There aren't line delimiters in PCL, since the printer doesn't care about "lines" in a control file. Just read the file in fixed-length chunks to do your manipulations. It shouldn't matter how many bytes you process at a time, so I'd choose a relatively large buffer (32K or so).

...roboticus

I figured all the commands begin with ESC control code.

Since each command starts with the escape character, set $/ = chr( 27 ).

I dumped a 300 page pdf to a PCL5 printer and the ran over the 300MB file produced counting the length of each 'command' using the following one-liner:

perl -e"BEGIN{ binmode STDIN, ':raw' }" 
-l -033 
-ne"$l{length()}++}{ print $_, '::', $l{$_} for sort{$a<=>$b} keys %l"
+ 
HP-PCL5.bin
[download]

The results showed that the maximium individual readline length was <2MB, with the vast majority being less than 1k:

0::1048
1::610
2::332
3::2763
4::15235
5::902
6::4896
7::2195
8::2448
9::955
10::9585
11::735
12::766
13::1399
14::30537
15::2323
16::1089
17::399
18::54322
19::1879
20::611
21::171
22::107
23::408
24::1071
25::720
26::738
27::1748
28::1374
29::2025
30::5380
31::3359
32::4704
33::2684
34::4027
35::2016
36::2349
37::1011
38::672
39::1
40::338
41::338
42::2
43::336
44::1
45::335
47::2
49::2
50::1
51::1
54::335
55::1
56::1
57::3
58::335
59::338
60::334
61::336
62::1002
63::1
64::335
67::334
68::335
69::337
72::334
80::1
83::1
90::1
94::1
122::10
230::2
232::6
233::2
242::74
243::2
352::2
353::2
356::2
357::2
362::9
363::2
788::1
2627::1
3363::1
4019::2
6929::1
7045::1
7163::1
7445::1
7972::1
9683::1
9703::1
9726::1
9754::1
...
998164::1
1001945::1
1008451::1
1016923::1
1017472::1
1019396::1
1023221::1
1030445::1
1032125::1
1044854::1
1049920::1
1056328::1
1056862::1
1060228::1
1063015::1
1065778::1
1066362::1
1067272::1
1068292::1
1069415::1
1070494::1
1071336::1
1072448::1
1072832::1
1073203::1
1075300::1
1076627::1
1082431::1
1083135::1
1097793::1
1098097::1
1100634::1
1101911::1
1103123::1
1107700::1
1109616::1
1111129::1
1113723::1
1116752::1
1126199::1
1129660::1
1132176::1
1136614::1
1142884::1
1144724::1
1162069::1
1164751::1
1167526::1
1172941::1
1174051::1
1174803::1
1178963::1
1181757::1
1209556::1
1227153::1
1241712::1
1241953::1
1255729::1
1264951::1
1265598::1
1267717::1
1269103::1
1269839::1
1273652::1
1275352::1
1278748::1
1279336::1
1291701::1
1298282::1
1305369::1
1326645::1
1355690::1
1361723::1
1373787::1
1382753::1
1393848::1
1433523::1
1465612::1
1571234::1
1586972::1
1595487::1
1620081::1
1630469::1
1643933::1
1653299::1
1694273::1
1712694::1
[download]

What is generating this PCL? A cleaner approach may be to edit the source file either by the use of a module or automating the source application.

Hi,

Thanks for responding. I've searched for CPAN modules but there isn't any that will edit the PCL files. There's one PCL::Simple to create a PCL file. So, I'm out of option there.

The header of one such file says this: ESC%-12345X@PJL COMMENT HP LaserJet 4100 Series PCL

I read somewhere that most of the PCL files begin with this statement but again some files miss this information. I've referred to PCL command reference document to understand the characters in the file. But it appears too tedious to follow the entire PCL file.

Could you tell me what you mean by automating the source application?

Thanks,
Thilak

I've referred to PCL command reference document to understand the characters in the file. But it appears too tedious to follow the entire PCL file.

I don't think there really are any other options.  As PCL consists of escape sequences (of varying length) intermixed with graphics (pixel) data and maybe plain text, you won't have much luck finding a "record" separator.  In other words, to really know what is what in the file, you'd have to parse or "understand" each escape sequence...

What exactly do you need to edit?  (and why, me wonders...)

I was trying to understand where these PCL files are coming from, and what you want to change.

Say you were using an application, for example Microsoft Word to create documents and save them as PCL files (you can setup a 'dummy' printer driver to output a pcl file to a certain directory. In such a scenario I'd prefer to make the changes you need in the source word document by automating it via Win32::OLE. This solution is easier to maintain, PCL has various version (1-6), PCL files aren't as easy to edit as a text/Word/PDF file.