How to use perl dbmopen on Windows and Linux - windows

I have a perl script that runs fine on Linux but fails on Windows at this point:
$freq{total} = 0;
dbmopen(%freq,$dictfile,0666) || die "Error: Cannot open dbmfile $dictfile";
$dictfile points to the proper location on the respective platforms. Changing the 0666 file permissions does not help. The file to open is a text file encoded in gb18030.
Is there a trick? Do I need to declare the encoding to open it on Window? Or possibly a different perl distro on Windows. I'm using Strawberry Perl.
Thanks.

Edit: Sorry, if I'm stating the obvious, but I just re-read the question. When you say
The file to open is a text file encoded in gb18030.
Do you mean a plain text file?
If so I think thats your problem. dbmopen is for indexed database file, ideally created by dbmopen in a previous run of you perl program. For plain text files you cannot bind them to hashes.
My previous resonse...
It works for me on Windows with Strawberry perl 5.12.1 running on Windows7x64. Which windows perl are you using? Make sure your installation has at least one of the DBM modules with it.
Some other points which might help:
You should include $! in your die statement, it will give you the error message for the failed open. So hopefully answer your question.
dbmopen will clear the contents of the %freq hash, so you will lose $freq{total} (because its 0 you may not notice). Usual pattern is: dbmopen, change some hash values, dbmclose
Edits:
$! is the variable which contains the error test of any failed "system" call. So you open line should be something like:
dbmopen(%freq,$dictfile,0666) || die "Error: Cannot open dbmfile $dictfile: $!";
To check for the standard DBM modules you can run the following from the command prompt
for %m in ( DB_File GDBM_File SDBM_File NDBM_File ODBM_File ) do #perl -M%m -e "print qq(%m: $%m::VERSION\n)"
For me that gives:
DB_File: 1.82
GDBM_File: 1.10
SDBM_File: 1.06
Can't locate NDBM_File.pm in #INC (#INC contains: C:/Nerd/StrawberryPerl/perl/site/lib C:/Nerd/StrawberryPerl/perl/vendor/lib C:/Nerd/StrawberryPerl/perl/lib .)
.
BEGIN failed--compilation aborted.
Can't locate ODBM_File.pm in #INC (#INC contains: C:/Nerd/StrawberryPerl/perl/site/lib C:/Nerd/StrawberryPerl/perl/vendor/lib C:/Nerd/StrawberryPerl/perl/lib .)
.
BEGIN failed--compilation aborted.
Which effectively meands I have DB_File, GDBM_File, and SDBM_File. But not NDBM_File or ODBM_File. Sorry I don't know how to find out which module dbmopen uses by default.
Personally I always use a specific module and then use the tie operator instead of dbmopen.

Related

Where is libpcap.dylib?

I able to load libpcap.dylib which is confusing cause I can't figure out the actual file location. Doing find / -name libpcap.A.dylib or libpcap.dylib says no such file.
Also finder search with libpcap just results in libpcap.A.tbd and libpcap.rb.
libpcap.A.tbd shows "Install location /usr/lib/libpcap.A.dylib", but it does not actually exist there.
I wanted to locate the actual dylib file cause I running into issue with being able to import function, So I wanted to check file to make sure I have function names correct.
So I wanted to check file to make sure I have function names correct.
The first thing to check is the pcap man page - from the command line, it'd be
man pcap
It's a bit long, but it should mention all the functions available in libpcap; it may be easier than
nm /usr/lib/libpcap.dylib | egrep ' T '
(and doesn't require you to remember that the leading underscores in the output of that command are NOT part of the name of the function, they're a leftover from ancient UNIX history).
Where is libpcap.dylib?
/usr/lib/libpcap.A.dylib. /usr/lib/libpcap.dylib is a symbolic link to it.

Perl code doesn't run in a bash script with scheduling of crontab

I want to schedule my Perl code to be run every day at a specific time. so I put the below code in bash file:
Automate.sh
#!/bin/sh
perl /tmp/Taps/perl.pl
The schedule has been specified in below path:
10 17 * * * sh /tmp/Taps/Automate.sh > /tmp/Taps/result.log
When the time arrived to 17:10 the .sh file hasn't been running. however, when I run ./Automate.sh (manually) it is running and I see the result. I don't know what is the problem.
Perl Code
#!/usr/bin/perl -w
use strict;
use warnings;
use Data::Dumper;
use XML::Dumper;
use TAP3::Tap3edit;
$Data::Dumper::Indent=1;
$Data::Dumper::Useqq=1;
my $dump = new XML::Dumper;
use File::Basename;
my $perl='';
my $xml='';
my $tap3 = TAP3::Tap3edit->new();
foreach my $file(glob '/tmp/Taps/X*')
{
$files= basename($file);
$tap3->decode($files) || die $tap3->error;
}
my $filename=$files.".xml\n";
$perl = $tap3->structure;
$dump->pl2xml($perl, $filename);
print "Done \n";
error:
No such file or directory for file X94 at /tmp/Taps/perl.pl line 22.
X94.xml
foreach my $file(glob 'Taps/X*') -- when you're running from cron, your current directory is /. You'll want to provide the full path to that Taps directory. Also specify the output directory for Out.xml
Cron uses a minimal environment and a short $PATH, which may not necessarily include the expected path to perl. Try specifying this path fully. Or source your shell settings before running the script.
There are a lot of things that can go wrong here. The most obvious and certain one is that if you use a glob to find the file in directory "Taps", then remove the directory from the file name by using basename, then Perl cannot find the file. Not quite sure what you are trying to achieve there. The file names from the glob will be for example Taps/Xfoo, a relative path to the working directory. If you try to access Xfoo from the working directory, that file will not be found (or the wrong file will be found).
This should also (probably) lead to a fatal error, which should be reported in your error log. (Assuming that the decode function returns a false value upon error, which is not certain.) If no errors are reported in your error log, that is a sign the program does not run at all. Or it could be that decode does not return false on missing file, and the file is considered to be empty.
I assume that when you test the program, you cd to /tmp and run it, or your "Taps" directory is in your home directory. So you are making assumptions about where your program looks for the files. You should be certain where it looks for files, probably by using only absolute paths.
Another simple error might be that crontab does not have permission to execute the file, or no read access to "Taps".
Edit:
Other complications in your code:
You include Data::Dumper, but never actually use that module.
$xml variable is not used.
$files variable not declared (this code would never run with use strict)
Your $files variable is outside your foreach loop, which means it will only run once. Since you use glob I assumed you were reading more than one file, in which case this solution will probably not do what you want. It is also possible that you are using a glob because the file name can change, e.g. X93, X94, etc. In that case you will read the last file name returned by the glob. But this looks like a weak link in your logic.
You add a newline \n to a file name, which is strange.

random file name in perl generated with unusual characters

Using this perl code below, I try to output some names in a random generated file. But the files are created with weird characters like this:
"snp-list-boo.dwjEUq5Wu^J.txt"
And, obviously when my code looks for these files it says not such file. Also, when I try open the files using "vi", they open like this
vi 'temporary-files/snp-list-boo.dwjEUq5Wu
.txt'
i.e. with a "new line" in the file name. Someone please help me understand and solve this weird issue. Thanks much!
code:
my $tfile = `mktemp boo.XXXXXXXXX`;
my $fh = "";
foreach my $keys (keys %POS_HASH){
open ($fh, '>>', "temporary-files/snp-list-$tfile.txt");
print $fh "$keys $POS_HASH{$keys}\n";
close $fh;
}
mktemp returns a line feed character in its output that you need to chop() or chomp() first.
Instead of using the external mktemp program, why don't you go with File::Temp instead?
Using external programs unnecessarily is a bad idea for a few reasons.
The external program that you use might not be available on all of the systems where your code runs. You are therefore making your program less portable.
Spawning a new sub-shell to run an external program is a lot slower than just doing the work in your current environment.
The values you get back from the external program are likely to have a newline character attached. And you might forget to remove it.
It's the last one that is burning you here. But the others still apply as well.
Perl's standard library has, for many, many years included the File::Temp module which creates temporary files for you without the need to use an external program.
use File::Temp qw/ tempfile /;
# It even opens it and gives you the filehandle.
($fh, $filename) = tempfile();

Ruby: No such file or directory -- C:\Documents <LoadError>

I'm just learning Ruby and making a simple Hello World program, put for some reason the command prompt can not find the directory (which is C:\Documents and Settings\Matt\My Documents\Ruby Testing Zone\hello.rb). With the directory set to C:\Ruby193\bin, I tried to type this command to run my program:
ruby C:\Documents and Settings\Matt\My Documents\Ruby Testing Zone\hello.rb
And I end up with this error:
ruby: No such file or directory -- C:\Documents <LoadError>
I have checked many times to make sure I'm not misspelling any part of the file name. What is going on?
Put double-quotes around the whole filename. Windows won't treat it as a single parameter otherwise.
In your open command, make sure that the spaces between Documents, and, and Settings are proceded with a backslash. In other words, here's what the path should be:
C:\\Documents\ and\ Settings\\Matt\\My\ Documents\\Ruby\ Testing\ Zone\\hello.rb
Or, replace the double-backslashes with slashes:
C:/Documents\ and\ Settings/Matt/My\ Documents/Ruby\ Testing\ Zone/hello.rb

Programming a Filter/Backend to 'Print to PDF' with CUPS from any Mac OS X application

Okay so here is what I want to do. I want to add a print option that prints whatever the user's document is to a PDF and adds some headers before sending it off to a device.
I guess my questions are: how do I add a virtual "printer" driver for the user that will launch the application I've been developing that will make the PDF (or make the PDF and launch my application with references to the newly generated PDF)? How do I interface with CUPS to generate the PDF? I'm not sure I'm being clear, so let me know if more information would be helpful.
I've worked through this printing with CUPS tutorial and seem to get everything set up okay, but the file never seems to appear in the appropriate temporary location. And if anyone is looking for a user-end PDF-printer, this cups-pdf-for-mac-os-x is one that works through the installer, however I have the same issue of no file appearing in the indicated directory when I download the source and follow the instructions in the readme. If anyone can get either of these to work on a mac through the terminal, please let me know step-by-step how you did it.
The way to go is this:
Set up a print queue with any driver you like. But I recommend to use a PostScript driver/PPD. (A PostScript PPD is one which does not contain any *cupsFilter: ... line.):
Initially, use the (educational) CUPS backend named 2dir. That one can be copied from this website: KDE Printing Developer Tools Wiki. Make sure when copying that you get the line endings right (Unix-like).
Commandline to set up the initial queue:
lpadmin \
-p pdfqueue \
-v 2dir:/tmp/pdfqueue \
-E \
-P /path/to/postscript-printer.ppd
The 2dir backend now will write all output to directory /tmp/pdfqueue/ and it will use a uniq name for each job. Each result should for now be a PostScript file. (with none of the modifications you want yet).
Locate the PPD used by this queue in /etc/cups/ppd/ (its name should be pdfqueue.ppd).
Add the following line (best, near the top of the PPD):
*cupsFilter: "application/pdf 0 -" (Make sure the *cupsFilter starts at the very beginning of the line.) This line tells cupsd to auto-setup a filtering chain that produces PDF and then call the last filter named '-' before it sends the file via a backend to a printer. That '-' filter is a special one: it does nothing, it is a passthrough filter.
Re-start the CUPS scheduler:sudo launchctl unload /System/Library/LaunchDaemons/org.cups.cupsd.plist
sudo launchctl load /System/Library/LaunchDaemons/org.cups.cupsd.plist
From now on your pdfqueue will cause each job printed to it to end up as PDF in /tmp/pdfqueue/*.pdf.
Study the 2dir backend script. It's simple Bash, and reasonably well commented.
Modify the 2dir in a way that adds your desired modifications to your PDF before saving on the result in /tmp/pdfqueue/*.pdf...
Update: Looks like I forgot 2 quotes in my originally prescribed *cupsFilter: ... line above. Sorry!
I really wish I could accept two answers because I don't think I could have done this without all of #Kurt Pfeifle 's help for Mac specifics and just understanding printer drivers and locations of files. But here's what I did:
Download the source code from codepoet cups-pdf-for-mac-os-x. (For non-macs, you can look at http://www.cups-pdf.de/) The readme is greatly detailed and if you read all of the instructions carefully, it will work, however I had a little trouble getting all the pieces, so I will outline exactly what I did in the hopes of saving someone else some trouble. For this, the directory with the source code is called "cups-pdfdownloaddir".
Compile cups-pdf.c contained in the src folder as the readme specifies:
gcc -09 -s -lcups -o cups-pdf cups-pdf.c
There may be a warning: ld: warning: option -s is obsolete and being ignored, but this posed no issue for me. Copy the binary into /usr/libexec/cups/backend. You will likely have to the sudo command, which will prompt you for your password. For example:
sudo cp /cups-pdfdownloaddir/src/cups-pdf /usr/libexec/cups/backend
Also, don't forget to change the permissions on this file--it needs root permissions (700) which can be changed with the following after moving cupd-pdf into the backend directory:
sudo chmod 700 /usr/libexec/cups/backend/cups-pdf
Edit the file contained in /cups-pdfdownloaddir/extra/cups-pdf.conf. Under the "PDF Conversion Settings" header, find a line under the GhostScript that reads #GhostScript /usr/bin/gs. I did not uncomment it in case I needed it, but simply added beneath it the line Ghostscript /usr/bin/pstopdf. (There should be no pre-cursor # for any of these modifications)
Find the line under GSCall that reads #GSCall %s -q -dCompatibilityLevel=%s -dNOPAUSE -dBATCH -dSAFER -sDEVICE=pdfwrite -sOutputFile="%s" -dAutoRotatePage\
s=/PageByPage -dAutoFilterColorImages=false -dColorImageFilter=/FlateEncode -dPDFSETTINGS=/prepress -c .setpdfwrite \
-f %s Again without uncommenting this, under this I added the line GSCall %s %s -o %s %s
Find the line under PDFVer that reads #PDFVer 1.4 and change it to PDFVer, no spaces or following characters.
Now save and exit editing before copying this file to /etc/cups with the following command
sudo cp cups-pdfdownloaddir/extra/cups-pdf.conf /etc/cups
Be careful of editing in a text editor because newlines in UNIX and Mac environments are different and can potentially ruin scripts. You can always use a perl command to remove them, but I'm paranoid and prefer not to deal with it in the first place.
You should now be able to open a program (e.g. Word, Excel, ...) and select File >> Print and find an available printer called CUPS-PDF. Print to this printer, and you should find your pdfs in /var/spool/cups-pdf/yourusername/ by default.
*Also, I figured this might be helpful because it helped me: if something gets screwed up in following these directions and you need to start over/get rid of it, in order to remove the driver you need to (1) remove the cups-pdf backend from /usr/libexec/cups/backend (2) remove the cups-pdf.conf from /etc/cups/ (3) Go into System Preferences >> Print & Fax and delete the CUPS-PDF printer.
This is how I successfully set up a pdf backend/filter for myself, however there are more details, and other information on customization contained in the readme file. Hope this helps someone else!

Resources