Re: Are there any ALSA Perl Modules?

[Shlomi Fish]

hi Martin,

On Mon, 29 Jan 2024 22:38:27 -0600
"Martin McCormick"  wrote:

> Shlomi Fish  writes:
> > hi Martin,
> > you can try using an FFI, eg:
> > 
> > https://metacpan.org/dist/Inline-C/view/lib/Inline/C.pod
> > 
> > https://metacpan.org/dist/Inline-Python/view/Python.pod
> > 
> > https://metacpan.org/pod/FFI::Platypus  
> 
> Many thanks.  I am glad I asked the question but it has taken me
> some time to digest your answer as I wasn't familiar with the
> term FFI so, after exercising duckduckgo, I now know those
> letters stand for Foreign Function Interface which makes perfect
> sense based on what needs to be done.  Unfortunately, FFI's are
> usually used by higher-level languages to take advantage of the
> capabilities found in lower-level languages such as C which is
> closer to assembler and can efficiently access the hardware such
> as an audio or video device.
> 

I meant that you can use Inline::C or perlxs or similar to write
wrappers/bindings for libalsa/etc.

>   I was hoping there might be a perl module like a
> fictional one I will call Device::ALSA which would understand the
> syntax used in capturing audio from a microphone or line input,
> like a microphone input, only not as sensitive, where one
> customarily feeds sound from the output of whatever one is
> recording from.
> 
>   There are standard alsa conventions for setting sample
> rate and other parameters which I mentioned in the earlier
> posting so if one knows what sort of digital stream they nead,
> they just stuff those values in to the function whose output is
> that stream of digital  data.  What you do with those data is up
> to you but the module takes care of getting the bits from the
> hardware or sending the bits to your speakers or headphones and
> would also support the alsa plugins which are used by the arecord
> and aplay utilities for added capabilities.
> 
>   I can understand why there is no perl module like
> Device::alsa because it would not be portable between Windows and
> Linus.  The l in alsa is for Linux so basically, I was just
> curious to see if anything like Device::ALSA existed and it
> apparently does not exist.
> 

Devs *have* written linux-only or mswindows-only perl5/CPAN modules.

>   Anyway, the FFI concept will probably someday come in
> handy for a different project so I will continue with the C I was
> working on.
> 
>   Thanks again.
> 
> Martin
> 



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Re: Are there any ALSA Perl Modules?

[Shlomi Fish]

hi Martin,

On Sun, 28 Jan 2024 13:27:45 -0600
"Martin McCormick"  wrote:

> Several years ago, I wrote some C code which turns one's
> computer's sound interface in to a sound-activated recorder that
> I could then connect to radio receivers or microphones and record
> when audio started and stop recording when there is nothing but
> silence.  One essentially sets a sound card to record
> continuously but the sound samples go through code that knows
> what silence looks like.  In short, silence looks like samples
> whose numeric value is exactly half-way between the lowest and
> highest voltage that the analog-to-digital converter reads,
> commonly either 32,767 representing silence, give or take a count
> or two due to digital sampling errors or decimal 128, hex 80 for
> 8-bit mono audio.
> 
>   The Advanced Linux Sound Architecture Project has C library
> functions for setting sample rates, mono, stereo, big or little
> endianness and 8 or 16-bit audio, whatever one needs for their
> application.  One can even define samples as signed or unsigned
> integers.
> 
>   Once one gets a stream of ints which are usually 32-bits
> wide for stereo or 16-bit shorts for mono, the sound processing
> can begin which C is really good at but perl is just as good at
> so if one could get the same alsa modules which are used by aplay
> and arecord for setting up one's audio interfaces or sound cards,
> the manipulation of those data that was done in C could also be
> done in perl without hardly any modification to it at all.
> 
>   Perl has just the right mix of low-level logic and
> bitwise operators plus a much more easy-to-use string handling
> capability which is why I am asking this question.
> 
>   I may be looking in the wrong places but, so far, I seem
> to be batting zeros when looking for perl and alsa together.
>

you can try using an FFI, eg:

https://metacpan.org/dist/Inline-C/view/lib/Inline/C.pod

https://metacpan.org/dist/Inline-Python/view/Python.pod

https://metacpan.org/pod/FFI::Platypus
 
>   Any good ideas are greatly appreciated, here.
> 
>   Martin McCormick
> 



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Re: Knowledge for a basic programmer and advanced programmer

[Shlomi Fish]

On Sat, 16 Dec 2023 08:10:49 -0600
William Torrez Corea  wrote:

> What needs to know a basic and advanced programmer?
> 
> I am a basic programmer, I don't have enough experience to be an advanced
> programmer.
> 
> How many years of experience must an advanced programmer have?
> 

hi William,

I answered many of your questions in the FAQs I comaint. List here:

https://www.shlomifish.org/meta/FAQ/which_faqs_do_you_comaint.xhtml

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Re: Performance Issue

[Shlomi Fish]

hi,

On Fri, 16 Jun 2023 10:37:07 +0200
LEROYER Benoit  wrote:

> Hello,
> I am usually used perl 5 on Centos system and I  recently installed a Rocky
> Linux system. When I execute an important perl program on Centos 7 it is
> very fast but the same program on Rocky Linux 8 is very slow. The server
> hardware is similar (RAM / Speed disk, CPU ...)
> Have you some ideas about this issue ?
> 

please see:  https://perl-begin.org/topics/optimising-and-profiling/ .

> Perl Version on Rocky Linux 8 is 5.26
> Perl Version on Centos 7 is 5.16
> 
> Thanks



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Re: Recommendations for setting up local Perl dev environment

[Shlomi Fish]

hi all,

On Wed, 24 May 2023 09:25:46 +0800
Ken Peng  wrote:

> On 2023-05-24 09:21, Joe Sliva Jr. wrote:
> > I've been on this list for years but haven't actually used Perl lately.
> > That being said, I have an old Perl script that I would like to start
> > working with again but would prefer to work on it within a local dev
> > environment.
> > 
> > Can anyone please recommend a local Perl dev install that would work on
> > Windows?  
> 
> Maybe this one?
> https://strawberryperl.com/
> 

strawberry perl is FOSS and decent. but note that it seems like windows will
become more GNU-like:
https://www.shlomifish.org/humour/bits/facts/Windows-Update/#see_also

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Re: json to disk

[Shlomi Fish]

hi, Tom,


On Tue, 23 May 2023 11:53:25 +0800
"Tom Reed"  wrote:

> Hello list,
> 
> How can I sync json object to disk? so that other processes (or next
> startup) can use this json.
> 

see https://metacpan.org/pod/JSON::MaybeXS ; make sure to use 'canonical'.

> Thanks.
> 
> 



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Re: How to can develop a program

[Shlomi Fish]

Hi William!

On Mon, 1 Aug 2022 14:50:21 -0600
William Torrez Corea  wrote:

> On Mon, Aug 1, 2022 at 8:16 AM Christian Walde 
> wrote:
> 
> > On Sat, 23 Jul 2022 21:03:18 +0200, William Torrez Corea <  
> > willitc9...@gmail.com> wrote:  
> >
> > My goal: I want to create
> >
> >
> > Being that you barely know anything about Perl, you should start with
> > learning how Perl works by reading Modern Perl and Ovid's Beginning Perl.
> >
> > Right now you're doing the moral equivalent of asking how to draw Mona
> > Lisa's eye when you don't even know which end of a paint brush paints.
> >
> > --
> > With regards,
> > Christian Walde
> >  
> 
> Do you have some roadmap that I can follow?. I receive the basics in my
> class of computation (control structure, data structure, algorithms,
> syntax, tools). I certainly have experience with C but never I make a long
> program in Perl.

see:

1. https://perl-begin.org/

2.
https://github.com/shlomif/Freenode-programming-channel-FAQ/blob/master/FAQ_with_ToC__generated.md

3. https://perl-begin.org/FAQs/freenode-perl/

welcome aboard!

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Re: Which distribution of PERL to use

[Shlomi Fish]

hi all,

On Mon, 4 Jul 2022 20:06:55 -0500
Mike  wrote:

> Strawberry Perl would be my preference if it works.
> 
> 

I agree that strawberry Perl is recommended.

See https://perl-begin.org/learn/Perl-perl-but-not-PERL/ though.

> Mike
> 
> 
> On 7/4/22 19:52, Mr. Faiz Ul Haq Zia wrote:
> > Hello,
> >   Which one of the PERL distribution should I use on windows 11.
> > regards
> > Faiz ul haque Zeya
> > Senior Associate professor BUKC  
> 



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Re: A Philosophical Point To Be Made: The Truth

[Shlomi Fish]

Hi Brandon!

On Sun, 17 Oct 2021 01:15:13 -0400
Brandon McCaig  wrote:

> Hello All,
> 
> It has been a while. I haven't been active on the list in years.
> Something much bigger has been stealing my focus. And now I think
> I might be ready to share it with the world.
> 
> Do be warned, I make best efforts to be inclusive of all, but I
> only know what I know. But if I'm right I have the answer to all
> of this for all of us.
> 
> https://castopulence.org/
> 
> To summarize, I think I know what the "correction" to
> insensitivity is. A better social network. Based upon the truth.
> 
> I wonder too if the Perl developers themselves might be
> interested in this discussion because of its relationship to
> linguistics and software. Though I dare not try to send it their
> way directly without a push (and maybe a direction).
> 
> Feedback, constructive or otherwise, is welcomed and encouraged.
> 

After reading that page, I still don't understand how the issue manifests
itself as well as how the proposed solution will be implemented. Perhaps try
giving concrete examples.

> Regards,
> 
> 
> 
> Brandon McCaig   <
> bamb...@castopulence.org>  
> Castopulence Software <https://www.castopulence.org/>
> Blog <https://www.bambams.ca/ <http://www.bambams.ca/>>
> perl -E '$_=q{V zrna gur orfg jvgu jung V fnl. }.
> q{Vg qbrfa'\''g nyjnlf fbhaq gung jnl.};
> tr/A-Ma-mN-Zn-z/N-Zn-zA-Ma-m/;say'



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Re: socket recive problem

[Shlomi Fish]

On Fri, 2 Apr 2021 13:46:35 -0400
Uri Guttman  wrote:

> On 4/2/21 4:47 AM, stefano cerbioni wrote:
> > hi i try to recive  a stream string  by  a client (write in C++) , if 
> > i use netcat ,  work ok but  when i use a  script in perl work 
> > partially , recive "Connection recieved from $name\n";,  but  $name 
> > is  blank , why ?? thanks
> > this is a script
> >  
> 
> don't use low level socket stuff as it is tricky to get correct. use the 
> IO::Socket module as it is correct and very easy to use.
> 

I agree. See:

* https://perl-begin.org/uses/multitasking/ ( IO::Async / etc.)

* https://metacpan.org/pod/IO::Socket and
https://metacpan.org/pod/IO::Socket::IP .

> uri
> 
> 



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Re: perl's pulsar client

[Shlomi Fish]

Hi Wesley!

On Wed, 27 Jan 2021 09:09:06 +0800
"Wesley Peng"  wrote:

> I saw apache pulsar has many clients in other languages such as python's:
> http://pulsar.apache.org/docs/en/client-libraries-python/
> 
> But it lacks a perl client library.
> Would anyone have the plan to make one?
> 
> Thanks.

See:

* https://metacpan.org/pod/distribution/Inline-Python/Python.pod

* http://shlomifishswiki.branchable.com/Self-Sufficiency/ :

* * “If I am not to myself, who will be? And if I am only to myself, who am I?
And if not now - when?” -- Hillel the Elder

* * https://www.cpan.org/misc/cpan-faq.html

If you want, you can pay someone to do the work for you. I charge 50 USD /
hour and abide by
https://www.shlomifish.org/humour/fortunes/show.cgi?id=shlomif-multiply-by-pi
, but there are other contractors you can hire.

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Re: question about change text in frame

[Shlomi Fish]

Hi Stefano!

On Sun, 29 Nov 2020 18:49:13 +0100
stefano cerbioni  wrote:

> Hi guys i find in internet  but nothing  , how  is possible change a text
> inside a frame ??
> 
> example i have this frame
> 

Please go over these documents:

* https://github.com/shlomif/how-to-share-code-online

* https://github.com/shlomif/writing-the-perfect-question

Non-runnable / not self-contained fragments make it hard for us to help you.

> 
> my $labeled_frame2 = $mw->LabFrame(-label => "FRAME",-labelside =>
> "bottom")->pack(-fill => "x");
> $labeled_frame2->Label(-text => "de ma de")->pack();
> 
> 
> i try
> with this
>  $labeled_frame2->configure (-text=>"BaoBABB");
> $mw->update();
> 
> but if is a simple  label like this :
> $mw->Label(-text => 'ciao')->pack(-anchor => 'nw');
> work but  in frame not  anyone  has an idea ?? thanks  in advice at all
> ciao



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Re: IO::Socket::Multicast::mcast_send

[Shlomi Fish]

Hi James,

On Sun, 5 Apr 2020 14:58:26 +0100
James Kerwin  wrote:

> Hi All,
> 
> I'm trying to connect to a smart bulb on my home WIFI using mcast_send
> in IO::Socket::Multicast.
> 
> It works on my main Linux Mint laptop. The same script does not work on my
> Raspberry PI.
> 
> Despite the script running as expected on one laptop I've checked that this
> is all set up correctly:
> 
> sub new {
> #my $class = shift;
> my $data  = {
> address => '239.255.255.250',
> port=> 1982,
> timeout => 3,
> devices => [],
> };
> return bless( $data );
> }
> 

It is a good idea to use bless with an explicit package name or just use
https://metacpan.org/pod/Moo or Moose or similar.

> my $socket = IO::Socket::Multicast->new(
> PeerAddr  => $self->{address},
> PeerPort  => $self->{port},
> Proto => "udp",
> ReuseAddr => 1,
> ) or croak $!;
> 
> But it's this part that fails on the PI:
> 

A few things to check:

1. Which OS/distro/version and perl version  on both machines?

2. Does it happen with the latest stable perl installed from source?

3. Did you try using https://en.wikipedia.org/wiki/GDB and/or perl -d:
https://perl-begin.org/topics/debugging/ ?

4. Is there anything in the rpi's firewall config?

For more advice, see https://github.com/shlomif/writing-the-perfect-question .

> $socket->mcast_send( $query, "$self->{address}:$self->{port}" ) or croak $!;
> 
> I've checked that $socket, $query and $self->{address}:$self->{port}
> contain the info I expect and they do.
> 
> On my Linux laptop I can use tcpdump and see the communication between
> laptop and bulb. Doing this on the Pi shows no communication. I've replaced
> the "croak" with "die "" so I can be certain it's failing at
> that point. I get the output "" (makes it easier to spot).
> 
> I've just used a command recently that allows me to access the specific ip
> and port of the lamp and it indicates the connection is successful. I'm out
> of ideas and if anyone can advise I'd appreciate it.
> 
> Slightly (very) out of my depth when it comes to ports and IPs etc.
> 
> Thanks,
> James



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Re: Unsatisfied dependencies detected during OALDERS/HTTP-Date-6.05.tar.gz

[Shlomi Fish]

Hi Jeffrey,

On Tue, 28 Jan 2020 18:34:50 -0500
Jeffrey Walton  wrote:

> Hi Everyone,
> 
> I'm trying to build Perl 5.30.1 from sources. I'm using:
> 
>./Configure -des -Dextras="HTTP::Daemon HTTP::Request Test::More
> Text::Template"
> 
> I'm seeing this in an endless loop (ad infinitum) on Fedora 1, Ubuntu
> 4, CentOS 5 and Fedora 31.
> 

I can reproduce this on fedora 31 x86-64 too.

> Running make for O/OA/OALDERS/HTTP-Date-6.05.tar.gz
>  Unsatisfied dependencies detected during 
>    OALDERS/HTTP-Date-6.05.tar.gz  
> Time::Zone [requires]
> Running make for module 'Time::Zone'
>   ATOOMIC/TimeDate-2.31.tar.gz
>   Has already been unwrapped into directory /root/.cpan/build/TimeDate-2.31-0
>   ATOOMIC/TimeDate-2.31.tar.gz
>   Has already been prepared
>   ATOOMIC/TimeDate-2.31.tar.gz
>   Has already been made
>   OALDERS/HTTP-Date-6.05.tar.gz
>   Has already been unwrapped into directory /root/.cpan/build/HTTP-Date-6.05-0
>   OALDERS/HTTP-Date-6.05.tar.gz
>   Has already been prepared
> Running make for O/OA/OALDERS/HTTP-Date-6.05.tar.gz
>  Unsatisfied dependencies detected during 
>    OALDERS/HTTP-Date-6.05.tar.gz  
> Time::Zone [requires]
> Running make for module 'Time::Zone'
>   ATOOMIC/TimeDate-2.31.tar.gz
>   Has already been unwrapped into directory /root/.cpan/build/TimeDate-2.31-0
>   ATOOMIC/TimeDate-2.31.tar.gz
>   Has already been prepared
>   ATOOMIC/TimeDate-2.31.tar.gz
>   Has already been made
>   OALDERS/HTTP-Date-6.05.tar.gz
>   Has already been unwrapped into directory /root/.cpan/build/HTTP-Date-6.05-0
>   OALDERS/HTTP-Date-6.05.tar.gz
>   Has already been prepared
> ...
> 
> I believe this break is partially due to building artifacts during
> 'make install'. The GNU Coding Standards explicitly states _DO NOT DO
> IT_. The only time things get built is during 'make'.
> 
> Does anyone know how to work around this (or any of the other build
> problems I am having)?
> 
> Do the Perl devs actually test this stuff?
> 

Perhaps we should report a bug.

> Jeff
> 



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Re: How to remove BerkleyDB dependency when building Perl from sources

[Shlomi Fish]

Hi Jeffrey,

On Tue, 28 Jan 2020 01:02:46 -0500
Jeffrey Walton  wrote:

> Hi Everyone,
> 
> I regression test on old machines. The older machines need an updated
> Git, SSH and Wget. To update Git, SSH and Wget I need to build a lot
> of dependent software. Perl is one of them.
> 
> On Fedora 1 while trying to build Perl 5.10.1:
> 

perl 5.10.1 is very old and no longer maintained (see what I wrote at
https://github.com/shlomif/supporting-older-perl5-releases ), but OTOH so is
Fedora 1.

> 
> I've tried to compile and run the following simple program:
> 
> #include 
> int main() { printf("Ok\n"); return(0); }
> 
> I used the command:
> 
> cc -o try -O2 -fno-strict-aliasing -pipe -I/usr/local/include
> -L/usr/local/lib try.c -lnsl -lgdbm -ldb -ldl -lm -lcrypt -lutil -lc
>  ./try
> 
> and I got the following output:
> 
> ./try: error while loading shared libraries: libdb-6.2.so: cannot open
> shared object file: No such file or directory
> The program compiled OK, but exited with status 127.
> You have a problem.  Shall I abort Configure [y]
> Ok.  Stopping Configure.
> 
> 
> I don't need database functions at this point so I would like to
> disable Berkley DB. 'Configure --help' does not list an option to
> disable the database gear.
> 
> I can't downgrade Perl because OpenSSL 1.1.x needs Perl 5.10. (OpenSSL
> really screwed us when the EOL'd 1.0.2 last month).
> 
> How do I remove or disable the BerkleyDB dependency?
> 

You can try editing the "Configure" script by hand. It is written in
https://en.wikipedia.org/wiki/Bourne_shell .

I recall trying to use Red Hat Linux 6.2 in a vbox VM and giving up after
the new openssl failed to compile using the old gcc there.

Good luck!

> Thanks in advance.
> 



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Re: reading data from a web site

[Shlomi Fish]

On Wed, 20 Nov 2019 19:52:46 +0100
hw  wrote:

> On Wednesday, November 20, 2019 3:29:00 AM CET Olivier wrote:
> > hw  writes:  
> > > Hi,
> > > 
> > > how can I read data from a web site which is using multiple frames and
> > > some
> > > javascript?  
> > 
> > Provided that the web site does not change too often and that they don't
> > implement stupid "security" features, this should not be too complicate.
> > 
> > Each frame is a web page, with it own URL. So you can examine the source
> > code of the web page to find the URL of the first frame and second frame
> > 
> > Them you can use any Perl library you like to load that URLand pars it
> > for what you are looking for.
> > 
> > Then use that data to load the second frame with a URL modified to
> > include the type of data you have selected.
> > 
> > Being frames makes it much easier, you hould not have to care about the
> > javascript too much.  
> 
> The web site seems to be created by a program running on the server, i. e. 
> there is not really a web site.  When I access it with lynx or with 
> WWW::Mechanize, the answer from the server says that neither frames, nor 
> javascript is supported, and it is not possible to log in.
> 
> Can WWW::Mechanize somehow trick the server into assuming that frames and 
> javascript are supported by the client?
> 

Hi!

See:

https://github.com/shlomif/Freenode-programming-channel-FAQ/blob/master/FAQ_with_ToC__generated.md#how-can-i-write-code-to-perform-operations-on-web-sites-for-me-that-otherwise-should-be-done-manually

(short URL: https://is.gd/ExAHTa )

Regards,

Shlomi


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Re: XML::Feed.pm perl on CentOS 7

[Shlomi Fish]

Hi Lars,

On Tue, 3 Sep 2019 08:06:36 +0300
Lars Noodén  wrote:

> I'm not finding CPAN's XML::Feed.pm for perl 5 for centos 7 via yum.
> 
> $ yum -q search all XML-Feed
> Warning: No matches found for: XML-Feed
> 
> $ grep PRETTY /etc/os-release
> PRETTY_NAME="CentOS Linux 7 (Core)"
> 
> Is there an additional package repository containing CPAN material for
> CentOS 7 which I can add?
> 

See https://pkgs.org/download/perl-XML-Feed .

Perhaps these pages will also help: 

* https://perl-begin.org/topics/cpan/

* https://perl-begin.org/topics/cpan/wrappers-for-distributions/


> /Lars
> 



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Re: Problem executing command via ssh

[Shlomi Fish]

Hi Eliza,

On Mon, 26 Aug 2019 18:37:10 +0800
Eliza  wrote:

> Hello,
> 
> on 2019/8/26 18:06, Shlomi Fish wrote:
> > seehttps://perl-begin.org/uses/remote-login-and-commands/  - use a CPAN
> > dist. Also note thathttps://metacpan.org/pod/IPC::Run  is a commonly cited
> > alternative to IPC::Open3 .  
> 
> Why not just using the native Net::SSH around modules.
> 
> https://metacpan.org/pod/Net::SSH
> https://metacpan.org/pod/Net::SSH::Perl
> https://metacpan.org/pod/distribution/Net-SSH-Expect/lib/Net/SSH/Expect.pod
> 

1. I linked to some of them on
https://perl-begin.org/uses/remote-login-and-commands/ (please follow and read
links)

2. No ssh module is part of the perl5 core -
https://shadow.cat/blog/matt-s-trout/but-i-cant-use-cpan/

3. What do you mean by "native"?


> regards,
> Eliza
> 



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Re: Problem executing command via ssh

[Shlomi Fish]

On Fri, 23 Aug 2019 19:16:55 +0300
Mario Galindez  wrote:

> Folks,
> 
> I need to execute a program in a remote machine, that takes its input from
> STDIN.
> 
> I created a user in such remote machine, and set my program as the shell
> for that account (so I don't need to provide shell access).
> 
> On my local node, I have this program:
> 
> #!/usr/bin/perl
> 
> use IPC::Open3;
> use POSIX;
> 
> 
> $inputfile= $ARGV[0];
> open(FILE, '<', "$ARGV[0]") or die $!;
> $command= "ssh user\@remotehost.com";
> $pid = open3('<', '>', '>', $command);
> 
> waitpid( $pid, 0 );
> 

Hi Mario,

see https://perl-begin.org/uses/remote-login-and-commands/ - use a CPAN dist.
Also note that https://metacpan.org/pod/IPC::Run is a commonly cited
alternative to IPC::Open3 .

Finally, see https://perl-begin.org/tutorials/bad-elements/ and
https://github.com/shlomif/Freenode-programming-channel-FAQ/blob/master/FAQ_with_ToC__generated.md#what-are-some-best-practices-in-programming-that-i-should-adopt
for some best practices advice.

> 
> What I expect is that I pass the name of the file as arguments of this
> program ($ARGV[0]), and the contents of this file is fed as STDIN of the
> child I've spawn with open3. This should be received as STDIN of my remote
> program, and the results of the remote program would be printed on STDOUT.
> 
> This works well. However, my program only reads the first line, and then
> terminates.
> 
> If I do a manual test, and do ssh u...@remotehost.com, and type multiple
> lines of input, then things work as expected.
> 
> Any clues?
> 
> Thanks!
> -m



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Re: Open and perl sub

[Shlomi Fish]

Hi Mike,

On Thu, 8 Aug 2019 15:40:42 +0100
Mike Martin via beginners  wrote:

> Is it possible to have the output of a perl module piped to open (open3 in
> my case), so I can use a file handle contains the output passed to sysread
> 
> Odd question I know
> 

you can use https://en.wikipedia.org/wiki/Fork_(system_call) ,
https://duckduckgo.com/?q=dup+unix=v140-1=web , "open >&" , etc.

> Thanks



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Re: how to catch die in a module

[Shlomi Fish]

Hi,

On Thu, 8 Aug 2019 08:21:24 +0530
Chankey Pathak  wrote:

> You can create a signal handler for die and handle the exception in there.
> Refer https://users.cs.cf.ac.uk/Dave.Marshall/PERL/node116.html
> 

Also see block eval - https://perldoc.pl/functions/eval - or one of its
wrappers like https://metacpan.org/pod/Try::Tiny .

Caveat: I maintain https://metacpan.org/pod/Error and recommend against using
the latter.

> On Thu, 8 Aug, 2019, 8:15 AM Eliza,  wrote:
> 
> > Hello,
> >
> > I use such a module from other people.
> > In this module there is the "die" statement, for example,
> >
> > connect(...) or die $!;
> >
> > Then my main program will die follow up this "die".
> > But I don't want the caller to die even if "die" was happened in the
> > module.
> > How to handle with it?
> >
> > Thank you.
> > Eliza
> >
> > --
> > To unsubscribe, e-mail: beginners-unsubscr...@perl.org
> > For additional commands, e-mail: beginners-h...@perl.org
> > http://learn.perl.org/
> >
> >
> >  



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Re: Install Problems: Net::Google::Spreadsheets

[Shlomi Fish]

are for release
> candidate testing
> t/release-kwalitee.t  skipped: these tests are for release
> candidate testing
> t/release-pod-syntax.t .. skipped: these tests are for release
> candidate testing
> t/release-unused-vars.t . skipped: these tests are for release
> candidate testing
> 
> Test Summary Report
> ---
> t/00_compile.t(Wstat: 256 Tests: 1 Failed: 1)
>   Failed test:  1
>   Non-zero exit status: 1
> t/01_new.t(Wstat: 512 Tests: 0 Failed: 0)
>   Non-zero exit status: 2
>   Parse errors: No plan found in TAP output
> Files=11, Tests=1,  1 wallclock secs ( 0.03 usr  0.01 sys +  0.98 cusr
>  0.07 csys =  1.09 CPU)
> Result: FAIL
>   HIROSE/Net-Google-Spreadsheets-V4-0.002.tar.gz
> one dependency not OK (Net::Google::DataAPI::Auth::OAuth2); additionally
> test harness failed
>   ./Build test -- NOT OK
> //hint// to see the cpan-testers results for installing this module, try:
>   reports HIROSE/Net-Google-Spreadsheets-V4-0.002.tar.gz
> Failed during this command:
>  TODDR/XML-Parser-2.44.tar.gz : make NO
>  MANWAR/XML-XPath-1.44.tar.gz : make_test NO one dependency
> not OK (XML::Parser); additionally test harness failed
>  MIYAGAWA/XML-Atom-0.42.tar.gz: make_test NO one dependency
> not OK (XML::XPath)
>  DANJOU/Net-Google-DataAPI-0.2805.tar.gz  : make_test NO one dependency
> not OK (XML::Atom); additionally test harness failed
>  HIROSE/Net-Google-Spreadsheets-V4-0.002.tar.gz: make_test NO one
> dependency not OK (Net::Google::DataAPI::Auth::OAuth2); additionally test
> harness failed



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Re: Device::SerialPort on debian Buster

[Shlomi Fish]

Hi Martin,

commenting on your code:

On Wed, 10 Jul 2019 08:51:08 -0500
"Martin McCormick"  wrote:

>   Before I take this too far, I want to make sure I am not
> doing something wrong with use of the Device::SerialPort module
> in perl.
> 
>   The code below talks to what it thinks is a RS-232 serial
> port and controlls a radio scanner so that one can program the
> scanner's settings and enter frequency and operational data.
> Don't worry about all that.  It used to work on debian stretch
> which is last year's version of debian.  After an upgrade to
> buster which is this year's version, also known as debian 10, all
> RS-232 ports appear to be dead.  Interestingly enough, a debian
> system running stretch, containing perl was upgraded to buster
> and serial communications between that system and a native serial
> port on it's mother board are fine.  The very same code ported to
> the buster system also fails with
> Can't call method "baudrate" on an undefined value at /home/martin/etc/mm
> line 121.
> 
>   It doesn't matter what serial port or whether it is
> native mother board hardware or what.  Serial ports are all
> broken right now.
> 
>   Here is the scanner control code.  I am sending it to see
> if I am using some deprecated method that is wrong to set the
> serial port or we really do have big trouble.
> 
>   Thanks for any and all constructive ideas.  Code follows:
> 
> 
> 
> #!/usr/bin/perl -w

See https://perl-begin.org/tutorials/bad-elements/#the-dash-w-flag .

> use strict;

good!

> use warnings::unused;
> use File::Basename;
> use File::Copy;
> use File::Spec;
> use Time::Local;
> use Device::SerialPort;
> 

Use explicit imports -
https://perl-begin.org/tutorials/bad-elements/#non_explicitly_imported_symbols

> sub waitfor {#Receive from serial port.
> 
> my $received = "";
> our $port;

"our" inside a function?

> 
> until ( "" ne $received ) {

double negative and perhaps use
https://stackoverflow.com/questions/223393/how-do-i-get-the-length-of-a-string-in-perl
> $received = $port->lookfor;
> }
> return ($received);
> }#Receive from serial port.
> 
> #no more sub routine code past this point
> 
> #main global variables
> our @dbstrings;
> 
> #main local variables
> my $response;
> my $cmd= "";
> my $ONEARG = "";
> 
> #my $counter = 1;
> 
> #Setup the comm port.
> my $dev = "/dev/ttyACM0";
> our $instring = "";
> our $port = Device::SerialPort->new("$dev");

why our?
> $port->baudrate(115200);
> $port->databits(8);
> $port->parity("none");
> $port->stopbits(1);
> $port->handshake("none");
> $port->read_const_time(500);# 500 milliseconds = 0.5 seconds
> $port->are_match( "\r", "\n", );# possible end strings
> 
> foreach $ONEARG (@ARGV) {   #each argument

see https://perl-begin.org/tutorials/bad-elements/#non_lexical_loop_iterators

> $ONEARG =~ s/^\s+//;
> $ONEARG =~ s/\s+$//;

perhaps use \A and \z

> $cmd = $cmd . " " . $ONEARG;

use ".="

> $cmd =~ s/^\s+//;
> $cmd =~ s/\s+$//;
> }#each argument
> 
> $cmd = uc $cmd;
> $port->write("$cmd\r");
> $instring = waitfor;


see https://perl-begin.org/tutorials/bad-elements/#declaring_all_vars_at_top .

> my @chars = split( "", $instring );
> foreach my $char (@chars) {#
> 
> #print ord($char);
> if ( $char =~ /[\,\s\.\-\+\_0-9A-Za-z]/ ) {#printable
> $response = $response . $char;

use .= and you can use https://perldoc.perl.org/functions/join.html and regex
matches. it is good that you follow
https://perl-begin.org/tutorials/bad-elements/#using-character-classes-with-unicode-text
.
> }#printable
> }#
> print "$response\n";
> $instring = "";
> exit(0);
>

Why the assignment right before exiting? 

I'm not sure if any of the issues I pointed are the culprit.

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Re: stupid question about to protect source code of perl web application scripting

[Shlomi Fish]

On Mon, 8 Jul 2019 15:07:41 +0700
Eko Budiharto  wrote:

> >> 2. if someone has a problem, he does not want to try to find a way to
> >> solve the problem first, and then he asks your help and then problem
> >> solved, then he is blaming the person who already helped him and
> >> claimed, that is his work. what will you do?
> >>  
> > What do you mean?
> >
> >  
> dear Shlomi,
> 
> what I mean in this one is the person has a problem, but he does not 
> make any efforts first, he just ask the solution from someone else. 
> After the problem is solved, he blames the person.
> 
> For example:
> 
> I have a problem and then I do not do anything or make my own effort and 
> then I ask your help to solve it for me. After the problem solved 
> because you helped me, I blame you instead you being grateful and thank 
> you and plus I said to anyone that I am the one who solved if instead of 
> your name.
> 

I understand now, thanks. That seems like a very ungrateful and "bastard"y
thing to do. I won't like it, but not sure how i'll act.

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Re: stupid question about to protect source code of perl web application scripting

[Shlomi Fish]

Hi,

On Mon, 8 Jul 2019 08:44:46 +0700
Eko Budiharto  wrote:

> dear all,
> 
> first of all, thank you for the respond of my inquiry. And then, there 
> is a few questions I would like to ask:
> 
> 1. if someone takes your works and then he steals the credit by claiming 
> the work is his work instead of your work, what will you do?
> 

First note that it never happened to me.

Anyway, in this case, I will try to find evidence that I originated the works
first, e.g:

* https://en.wikipedia.org/wiki/Wayback_Machine

* https://en.wikipedia.org/wiki/Version_control histories

* https://en.wikipedia.org/wiki/Internet_forum archives

Note that I think the most restrictive licences I used are
https://en.wikipedia.org/w/index.php?title=CC-by-nc-sa=no and
https://en.wikipedia.org/wiki/Affero_General_Public_License which also allow
asserting copyright on derivative changes.

If the person who claims my work is theirs does not sue me for infringement, I
will likely not care much:

* https://fc-solve.shlomifish.org/faq.html#abuse_of_fc_solve

* https://www.mail-archive.com/linux-il@cs.huji.ac.il/msg56378.html

> 2. if someone has a problem, he does not want to try to find a way to 
> solve the problem first, and then he asks your help and then problem 
> solved, then he is blaming the person who already helped him and 
> claimed, that is his work. what will you do?
> 

What do you mean?

> This is kind of some images of this dishonest person.
> 
> I do not mind to share my code to the person, if he does not have that 
> character.
> 
> So far, I am using the perl code for web application in a hosting 
> server. But this time, I have to create a web application on a on 
> premise server.
> 
> I am not an expert yet in perl and still learning although I know perl 
> when I got still in my university 19 years ago.
> 
> regards,
> 
> Eko Budiharto
> 
> 

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Re: stupid question about to protect source code of perl web application scripting

[Shlomi Fish]

Hi all,

On Sun, 7 Jul 2019 19:54:30 +1200
Kent Fredric  wrote:

> > On 7/6/19 11:21 PM, Eko Budiharto wrote:  
> > > it is a web application but it is on premise. The user is not honest.
> > > That's why I am trying to find a way to protect the source code like
> > > in java we can compile into java class and still can be run.  
> 
> That's a false sense of securtiy. A sufficiently "dishonest" person
> can decompile your class files back into source.
> 
> It may not be the original source, comments may be lost, function
> names and variables may become nonsensical, ( but this last part
> typically requires additional obfuscation beyond the standard java
> compiler )
> 
> But the logic, the interface, and all the metadata required to make
> backtraces remotely comprehensible, is all still there for anyone who
> wants to look.
> 

In addition see these FAQ replies:

*
https://perl-begin.org/FAQs/freenode-perl/#How_can_I_compile_my_code_to_obscure_.2F_obfuscate_the_source.3F

*
https://github.com/shlomif/Freenode-programming-channel-FAQ/blob/master/FAQ_with_ToC__generated.md#how-do-i-hideobscureencrypt-my-source-code-to-prevent-end-users-from-learning-how-it-works

This question is very old...


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Re: PAUSE

[Shlomi Fish]

Hi all,

can someone try to help Mike here?

On Sun, 30 Jun 2019 05:10:19 -0500
Mike  wrote:

> I understand that to upload a module to CPAN is need
> to obtain a PAUSE account.  I have tried twice to get
> that, but I don't receive an e-mail with a password.
> 
> http://www.mflan.com/temp/pause.jpg
> 
> If anybody can notify the PAUSE people that the PAUSE
> program appears to be broke, please do.
> 
> 
> 
> Mike
> 



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Re: can I use some kind of binary string?

[Shlomi Fish]

Hi,

On Sat, 18 May 2019 14:02:46 +0200
hwilmer  wrote:

> On 5/16/19 9:56 PM, Shlomi Fish wrote:
> > On Thu, 16 May 2019 13:13:16 +0200
> > hwilmer  wrote:
> >   
> >> On 5/11/19 11:07 AM, Shlomi Fish wrote:  
> [...]
> >>>> So I would want to use something like
> >>>>
> >>>>
> >>>> my $binary_data = `curl -k "https://www.example.com/some.jpg"`;
> >>>> 
> >>>
> >>> Perl distinguishes between 8-bit/binary strings and unicode ones. See
> >>> https://perldoc.perl.org/perlunitut.html .  
> >>
> >> What kind of string do I get when using backticks like in the above
> >> example?  
>  > [...]
> > Perhaps use open "-|" with an encoding - see
> > https://perldoc.perl.org/functions/binmode.html .  
> 
> I didn't know I could do that ...  I tried it and it works, too.
> 

Nice.

> >>> Note however that you should see
> >>> https://perl-begin.org/uses/web-automation/ and use a module instead of
> >>> trapping curl.exe's output. Perl has bindings to libcurl too if that is
> >>> what you want.  
> >>
> >> First I tried to use WWW::Mechanize, and that failed because it can't
> >> deal witch the self-signed certificates the web server is using.  I
> >> couldn't find anywhere in the documentation how to allow such
> >> certificates.  Otherwise it seemed to be able to do what I wanted.
> >>  
> > 
> > See
> > https://stackoverflow.com/questions/47662461/how-to-accept-self-signed-certificates-with-
> >  
> lwpuseragent
> 
> That gives an error: 'Bareword "IO::Socket::SSL::SSL_VERIFY_NONE" not 
> allowed while "strict subs" in use ...'.  But this works:
> 
>my $ua = LWP::UserAgent->new(
>  max_size => $MAX_DOWNLOAD_SIZE,
>  ssl_opts => {
>   ssl_verify => 0,
>   verify_hostname => 0
>  }
> );
> 

Great! Thanks for the tip.

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Re: can I use some kind of binary string?

[Shlomi Fish]

On Thu, 16 May 2019 13:13:16 +0200
hwilmer  wrote:

> On 5/11/19 11:07 AM, Shlomi Fish wrote:
> > Hi hwilmer,
> > 
> > On Fri, 10 May 2019 19:09:50 +0200
> > hwilmer  wrote:
> >   
> >> Hi,
> >>
> >> I would like to use curl to retrieve an image from a web server which I
> >> want to store in a table in a mariadb database without downloading the
> >> image to a file.  For this application, I do not want to store
> >> references to files stored in some file system instead.
> >>
> >> So I would want to use something like
> >>
> >>
> >> my $binary_data = `curl -k "https://www.example.com/some.jpg"`;
> >>  
> > 
> > Perl distinguishes between 8-bit/binary strings and unicode ones. See
> > https://perldoc.perl.org/perlunitut.html .  
> 
> What kind of string do I get when using backticks like in the above 
> example?  One that perl considers as a text string I could use stuff 
> like uc or lc on, or as a binary string I could use pack or unpack on? 
> Variables are without types, so there is no way to tell.  If I was using 
> curl to receive a text string, how would I know which encoding is being 
> used?  For all I know that could depend on the machine my program is 
> running on after lots of factors I would never know about.  And this 
> same encoding could happen to the image data.
> 
> Why would I use pack or unpack on the image data curl puts into the 
> string?  Do I need to worry that somewhere --- like in my program or in 
> some method DBI provides or somewhere else --- some kind of string 
> transformation might take place that damages the image data?  Is there a 
> way to tell perl that this is actually not a string but some binary data 
> that must not be transformed or encoded?
> 
> So far, it's working, but that could be just luck ...
> 

Perhaps use open "-|" with an encoding - see
https://perldoc.perl.org/functions/binmode.html .

> > Note however that you should see https://perl-begin.org/uses/web-automation/
> > and use a module instead of trapping curl.exe's output. Perl has bindings to
> > libcurl too if that is what you want.  
> 
> First I tried to use WWW::Mechanize, and that failed because it can't 
> deal witch the self-signed certificates the web server is using.  I 
> couldn't find anywhere in the documentation how to allow such 
> certificates.  Otherwise it seemed to be able to do what I wanted.
> 

See
https://stackoverflow.com/questions/47662461/how-to-accept-self-signed-certificates-with-lwpuseragent

> Using curl via the library bindings is somewhat going to lengths I would 
> rather avoid.
> 



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Re: can I use some kind of binary string?

[Shlomi Fish]

Hi hwilmer,

On Fri, 10 May 2019 19:09:50 +0200
hwilmer  wrote:

> Hi,
> 
> I would like to use curl to retrieve an image from a web server which I 
> want to store in a table in a mariadb database without downloading the 
> image to a file.  For this application, I do not want to store 
> references to files stored in some file system instead.
> 
> So I would want to use something like
> 
> 
> my $binary_data = `curl -k "https://www.example.com/some.jpg"`;
> 

Perl distinguishes between 8-bit/binary strings and unicode ones. See
https://perldoc.perl.org/perlunitut.html .

Note however that you should see https://perl-begin.org/uses/web-automation/
and use a module instead of trapping curl.exe's output. Perl has bindings to
libcurl too if that is what you want.

> 
> The image then needs to be inserted into a LONGBLOB field via DBI in 
> such a way that the image can be restored as it was.
> 
> Will string conversions or something prevent this from working?
> 
> What is the usual way to do this?  It is certainly not ideal to have no 
> check on the amount of data that might be retrieved from the web server, 
> regardless whether I save it to an intermediate file or not.
> 
> To make things more difficult, the web server is using a self-signed 
> certificate.
> 



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Re: proper use of TEMPLATE

[Shlomi Fish]

Hi Rick,

On Thu, 14 Mar 2019 12:14:59 -0500
Rick T  wrote:

> I’m sure this is a “newbie question,” but I am only a shade above that status
> and would appreciate some clarification.
> 
> I have
> 
> use TEMPLATE
> 

do you mean https://metacpan.org/pod/Template ?
> in my code to control whether the attribute 
> 
> selected 
> 
> appears with one of the < options> of the list following  in my
> served html document. Here’s one line from that list
> 
>  Full Course (1 credit)
> 
> My code can easily replace the correct var with ‘selected’ and the other vars
> on the list with a blank. But what should that blank be?
> 
> Should I make it an empty string, a space, undef, or something else? I can
> try them out to see what will work (perhaps all will work), but I want to
> know what is considered best practice and why.
> 

an empty string should be fine.

> Perhaps there’s even a whole better way to approach this! I will be grateful
> to chew over any and all comments you experienced people send me. Thanks!
> 
> Rick Triplett



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Re: covert perl code to binary

[Shlomi Fish]

Hi,

On Thu, 17 Jan 2019 17:48:50 +0200
"Octavian Rasnita"  wrote:

> From: "Chas. Owens" 
> 
> > The only way to truly hide code is to not give the code to the person
> > you don't want to see it.  Even languages like C have decompilers. If
> > you truly need to prevent people from seeing code, then your only real
> > option is to run a server and distribute a client that connects to the
> > server.  If all you need to is to discourage casual lookers from
> > seeing the source, then you only need something like Acme::Bleach.
> > Yes, you can unbleach the code, but it takes effort and knowledge and
> > with those no code is safe behind any form of obfuscation (including
> > compilation to binary).
> >
> > If you are trying to hide the code because you are distributing
> > secrets (like passwords, api keys, etc) in your code, then you have a
> > fundamental design issue that needs to be fixed.
> >  
> 
> 
> 
> Decompiling C/C++/asm code in a form that can be re-compiled again is hard 
> to do for most programmers.
> Finding/unhiding the provided Perl code is not as hard.
> 
> So the real answer is that if the protection of the source code is so 
> important, then Perl is not an appropriate programming language for this, 
> because it doesn't have a way of compiling the code and storing it in files 
> that can be distributed and ran by the final users. C/C++/Java/C# or even Go 
> or Python are better for this.
> 

Please see
https://github.com/shlomif/Freenode-programming-channel-FAQ/blob/master/FAQ.mdwn#how-do-i-hideobscureencrypt-my-source-code-to-prevent-end-users-from-learning-how-it-works

(short URL: https://is.gd/pLk1b2 )

Python is not suitable for that either. Also note that while decompiling is
problematic, https://en.wikipedia.org/wiki/Reverse_engineering is usually
doable with some effort if you wish to learn about a certain key technique.

> As far as I know, perlcc never really worked for complex programs. It might 
> work for Hello, world programs, but not fore more, so it is not a solution 
> either.
> 
> ActiveState PDK could be a good enough solution for hiding the source code, 
> but it is not a very clean solution that works well for any kind of 
> programs, and it doesn't compile the code.
> 
> Creating web-based apps that run on a server might not be a solution either, 
> because in some cases a local (desktop) app with a OS native interface is 
> needed.
> 
> Perl still has its advantages, but not for compiling/hiding code and for 
> distributing the programs to final users, and because it is used less and 
> less for new projects, probably it will never have that kind of advantage 
> unfortunately.
> 
> Other people used to recommend to distribute a license and put the loyers 
> sue those that don't respect it, but it is obvious that this is not a 
> solution either.
> 
> Perl is good only when is not necessary to hide the code, for example for 
> very complex web-based apps that can't be replaced with an already-made free 
> CMS, or for special programs that run on a server by a cron job, but not for 
> applications ran by common users on their desktop computers. 
> ...unfortunately.
> 
> --Octavian
> 



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Re: covert perl code to binary

[Shlomi Fish]

Hi Uday,

On Fri, 11 Jan 2019 15:29:23 +0530
Uday Vernekar  wrote:

> Hi all,
> 
> I have a perl code which I need to covert to binary so that nobody can see
> the code.
> 
> we used pp package to make the perl code binary but here the user can see
> the code which gets created in tmp.
> 
> Need help if anybody knows kindly reply
> 

first of all, see
https://github.com/shlomif/Freenode-programming-channel-FAQ/blob/master/FAQ.mdwn#how-do-i-hideobscureencrypt-my-source-code-to-prevent-end-users-from-learning-how-it-works

(short url: https://is.gd/pLk1b2 .)

Otherwise perhaps https://metacpan.org/pod/B::C will work for you or you can
try paying a C programmer to translate the code for you (I can do that!).

> With regards
> Uday V G



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Re: Perl Email and WuFoo Forms.

[Shlomi Fish]

Hi James,

On Tue, 2 Oct 2018 14:18:35 +0100
James Kerwin  wrote:

> Hi All,
> 
> I have a Perl script that pulls in some information, generates an email,
> sends the email to a person and provides a URL to a WuFoo form. This URL
> contains the information to populate most fields in the form and could
> populate all of the fields.
> 
> What I don't know is how to submit the form. WuFoo uses POST to submit
> forms so I'm quietly confident I can't trigger that via the URL (happy to
> be surprised!).
> 
> The email generated by Perl is plain text so far as I can tell, using the
> JavaScript API that WuFoo has is out of the question (again, very happy to
> be told otherwise).
> 
> Does anybody have any idea how I could go about this? I have access to a
> server in which to host scripts on etc. and I'm not necessarily looking for
> a hand-holding solution, just a nudge in the right direction would be
> brilliant.
>

see http://perl-begin.org/uses/web-automation/ and
https://github.com/shlomif/Freenode-programming-channel-FAQ/blob/master/FAQ.mdwn#how-can-i-write-code-to-perform-operations-on-web-sites-for-me-that-otherwise-should-be-done-manually

(short URL: https://is.gd/Tjo3KR .)

Regards,

Shlomi
 
> Thanks,
> James



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Re: reading form values from POST

[Shlomi Fish]

Hi Rick,

On Sun, 2 Sep 2018 16:04:26 -0500
Rick T  wrote:

> I am trying to wean myself from CGI.pm, an easy task for most of you, but I
> am a beginner. The code below works, but that does not mean it always will or
> that it cannot be improved. I found the main part of this in CGI Programming
> with Perl, which is 18 years old, and I’ve given up hoping that a new edition
> of it will come out. I’ve read somewhere that servers can give the wrong
> value for CONTENT_LENGTH, so I stuck in a second chance before bailing out;
> and of course this may not be necessary or done well.  I look forward to any
> and all comments. I also would appreciate any guidance on how I can learn
> more about CGI and how to deal with it. This book has been extremely valuable
> to me, but even I can see that some of its guidance is a bit creaky! — Rick
> 
> sub get_form_data {
> my $query = q{}; # Empty string
> my @name_value_pairs;
> if ( read( STDIN, $query, $ENV{'CONTENT_LENGTH'} ) 
>   == $ENV{CONTENT_LENGTH}
>){
> @name_value_pairs = split /&/, $query;
> }elsif (! read( STDIN, $query, $ENV{'CONTENT_LENGTH'} ) # Second chance
> == $ENV{CONTENT_LENGTH}
>){
> die "Trouble parsing POST request: $!"
> }
>

please  use a module - whether CGI.pm or other. See:

* https://leejo.github.io/2016/02/22/all_software_is_legacy/

* https://plackperl.org/

* https://metacpan.org/release/CGI-Minimal 

Thanks to Uri too.

Regards,

Shlomi Fish

> foreach my $pair (@name_value_pairs){
> my ($key, $value) = split /=/, $pair;
> chomp ($key, $value);
> $pf{$key} = $value;
>     }
> return;
> }
> 



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Re: slurp error

[Shlomi Fish]

Hi all!

On Fri, 27 Jul 2018 14:42:35 -0400
Uri Guttman  wrote:

> On 07/27/2018 02:37 PM, Rick T wrote:
> > I tried to implement some advice about slurping that I read on this 
> > mailing list (using local) but cannot get it to work. I get the 
> > message “Value of  construct can be "0"; test with defined() 
> > at line 23” (the $slurp = <$fh1> line). I’m using perl version 5.18.2 
> > installed in 2014.
> >
> > I’ve googled this error and think (ha!) I understand it, but though 
> > I’ve tried many changes, I cannot make the error go away. I need the 
> > advice of folks who are way ahead of me!
> >
> > Rick Triplett
> >
> >
> >  
> use File::Slurp ; #from cpan
> 

Please see
http://blogs.perl.org/users/leon_timmermans/2015/08/fileslurp-is-broken-and-wrong.html
and
https://www.reddit.com/r/perl/comments/3hfsqt/fileslurp_is_broken_and_wrong/
for better alternatives to File::Slurp .



> my $text = read_file( $file_to_convert ) ;
> $text =~ s/\r/\n/g;
> $text =~ s/\x0b//g ;
> 
> no need for xms if you aren't using those features.
> 
> uri
> 
> 
> 



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Re: tie a hash to a file

[Shlomi Fish]

On Wed, 01 Aug 2018 19:16:54 +0800
"Lauren C."  wrote:

> Do you know how to tie a hash to a disk file thus read by another process?
> 
> Currently my solution is writing the data to a JSON file and read it from the
> other program.
> 
> Thank you.
> 

See http://perl-begin.org/uses/databases/ . I also maintain this page -
http://www.shlomifish.org/open-source/resources/databases-list/ .

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Re: regex to get the rpm name version

[Shlomi Fish]

Hi Asad,

On Fri, 27 Jul 2018 18:24:39 +0530
Asad  wrote:

> Hi All ,
> 
>  I want to get a regex to actually get the rpm name and version for
> comparison :
> 
> 
> binutils-2.23.52.0.1-12.el7.x86_64",
> compat-libcap1-1.10-3.el7.x86_64"
> compat-libstdc++-33-3.2.3-71.el7.i686
> 
> (^[a-zA-Z0-9\-]*)\-\d'
> 
> First part of the regular expression is ^[a-zA-Z0-9\-]
> 
> which means search for anything that begins with a letter
> 
> (lower or upper) or a number up until you reach an
> 
> hyphen sign (‘-‘).
> 
> but it fails to match
> 
> compat-libstdc++-33-3.2.3-71.el7.i686
> 
> Please let me know what regex should i use to extract all 3
> 
> rpms.
> 
> Also let me know if there are web tools to build regex
> 
> Good websites for regex tutorials.
> 

for that, see:

* http://perl-begin.org/topics/regular-expressions/

* https://github.com/aloisdg/awesome-regex

* https://www.regular-expressions.info/


> 
> 
> 
> Thanks,
> 
> 
> 
> 
> 



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Re: regex matches Chinese characters

[Shlomi Fish]

Hi Lauren,

On Fri, 27 Jul 2018 11:28:42 +0800
"Lauren C."  wrote:

> greetings,
> 
> I was doing the log statistics stuff using perl.
> There are chinese characters in log items.
> I tried with regex to match them, but got no luck.
> 
> $ perl -mstrict  -le 'my $char="汉语"; print "it is chinese" if $char =~ 
> /\p{Han}+/'
> 
> $ perl -mstrict -mutf8 -le 'my $char="汉语"; print "it is chinese" if 
> $char =~ /\p{Han}+/'
> 
> both output nothing.
> 
> My terminal is UTF-8:
> 

According to http://perldoc.perl.org/perlrun.html , you probably need -Mstrict
and -Mutf8 instead of the lowercase -m, so "sub import" will get called:

shlomif@telaviv1:~$ perl -Mstrict -Mutf8 -le 'my $char="汉语"; print "it is
chinese" if $char =~ /\p{Han}+/'
it is chinese
shlomif@telaviv1:~$ 

HTH,

Shlomi

> $ locale
> LANG=en_US.UTF-8
> LANGUAGE=
> LC_CTYPE="en_US.UTF-8"
> LC_NUMERIC="en_US.UTF-8"
> LC_TIME="en_US.UTF-8"
> LC_COLLATE="en_US.UTF-8"
> LC_MONETARY="en_US.UTF-8"
> LC_MESSAGES="en_US.UTF-8"
> LC_PAPER="en_US.UTF-8"
> LC_NAME="en_US.UTF-8"
> LC_ADDRESS="en_US.UTF-8"
> LC_TELEPHONE="en_US.UTF-8"
> LC_MEASUREMENT="en_US.UTF-8"
> LC_IDENTIFICATION="en_US.UTF-8"
> LC_ALL=
> 
> 
> Can you help? thanks in advance.
> 



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Re: interpolation without double quotes

[Shlomi Fish]

On Thu, 5 Jul 2018 09:58:52 -0500
p...@reason.net wrote:

> Many thanks to Shlomi and Uri: as always, you’ve greatly boosted my
> understanding of Perl! — Rick
> 

You're welcome.


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Re: interpolation without double quotes

[Shlomi Fish]

Hi Rick,

On Wed, 4 Jul 2018 09:16:19 -0500
Rick T  wrote:

> The following line works, even though I forgot to double quote the variable.
> 
> my $student_directory =  '/data/students/' . $student_id;
> 

see http://perl-begin.org/tutorials/bad-elements/#vars_in_quotes . Perl often
stringifies expressions even outside interpolation, such as when being
string-concatenated.

> When I noticed this, I thought this was convenient: perl is trying to “do the
> right thing.” But I worry that leaving them out may be bad coding practice;
> if so, or you see other worthwhile improvements, please let me know.
> 
> More importantly, I wonder how perl knows to do this. Perhaps  context
> provided by the assignment operator or the concatenation operator? If there
> is a general rule on this, it would help me to know more widely when I can
> omit double quotes.
> 
> Thanks!
> 
> Rick Triplett


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Re: Replacing 10 year old web server

[Shlomi Fish]

Hi Gary!

On Fri, 29 Jun 2018 15:54:33 +0100
Gary Stainburn  wrote:

> I'm replacing my old F9 web server with a new C7 one.  While I've used RPM's 
> for most packages there have been times when I've had to use CPAN and PEAR.
> 
> For the PEAR items I'm able to do 
> 
> pear list -a > pear_list.txt
> 
> to get a list of all modules installed that way. Is there an equivelent 
> command for CPAN to tell me which modules I've installed that way?
> 

There are some answers for that here -
https://stackoverflow.com/questions/115425/how-do-i-get-a-list-of-installed-cpan-modules
 .
Found in a google search.

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Re: can not locate installe module

[Shlomi Fish]

On Mon, 4 Jun 2018 11:20:53 +0100
Gary Stainburn  wrote:

> On Monday 04 June 2018 10:39:28 Shlomi Fish wrote:
> > is there anything in https://en.wikipedia.org/wiki/Environment_variable ?  
> 
> I do have some interesting perl settings, although I have no idea where they 
> have come from.  This is a brand new Centos 7 install, and prior to trying to 
> install the three modules everything had been done by installing RPM's
> 
> This does seem to corroborate your theory below about it being local only to 
> root, and wh 'perl -c' works.  However, shouldn't the perldoc also have 
> worked in that instance?
> 
> [root@ollie2 ~]# set|grep -i perl
> PATH=/root/perl5/bin:/usr/lib64/qt-3.3/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/root/bin
> PERL5LIB=/root/perl5/lib/perl5:
> PERL_LOCAL_LIB_ROOT=:/root/perl5
> PERL_MB_OPT='--install_base /root/perl5'
> PERL_MM_OPT=INSTALL_BASE=/root/perl5
> if type perl &>/dev/null; then
> COMPREPLY=($( compgen -W '$( perl -e '"'"'while (($gid) = 
> (getgrent)[2]) { print $gid . "\n" }'"'"' )' -- "$cur" ));
> --perl-regexp
> if type perl &>/dev/null; then
> COMPREPLY=($( compgen -W '$( perl -e '"'"'while (($uid) = 
> (getpwent)[2]) { print $uid . "\n" }'"'"' )' -- "$cur" ));
> [root@ollie2 ~]#  
> 
> > Perhaps you have https://metacpan.org/pod/local::lib enabled or similar.  
> 
> I have checked and I do indeed have local::lib installed.  It got installed
> as a depencancy of perl-CPAN.rpm.  When I tried to remove it, it wouldn't 
> because of the dependancy.  When I removed both that and perl-CPAN that was 
> okay, although it didn't remove the Env Vars.
> 
> However, when I re-installed the perl-CPAN RPM it pulled perl-local-lib in 
> again too.
> 
> Looks like I need to move over to the Centos list as this appears to be a 
> Centos problem now rather than a perl one.
> 

good luck, and I am glad I could help.

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Re: Removing a Pattern using a Regular Expression

[Shlomi Fish]

Hi Dmitri,

On Thu, 14 Jun 2018 11:34:34 +0300
Дмитрий Ананьевский  wrote:

> On Wed, 13 Jun 2018 21:21:12 -0500
> "Martin McCormick"  wrote:
> 
> > I wrote a small perl program to more quickly read all the
> > subjects in an email list.  One of the things the script does is
> > to remove the mailing list name which repeats for every message
> > and consists of a [, some English text and finally a ].
> > 
> > I was able to write a RE that identifies that text and
> > cause the script to save that string in a variable called
> > $remove.  That part works and looks like:
> > 
> > foreach my $field (@fields) {#Assemble the new subject.
> > if($field =~ m/\[(.*?)\]/) 
> > { #$field is the blocked field.
> > $remove = $field;
> > } #field is the blocked field.
> > else
> > { #$field is not the blocked string.
> > $newest = $newest . $field;
> > } #$field is not the blocked string.
> > }#Assemble the new subject.
> > 
> > if ( $newest eq $previous ) {#Skip this iteration.
> > $newest = "";
> > next;
> > }#Skip this iteration.
> > else
> > { #they are different.
> > 
> > This is where things don't quite work yet.  At this
> > point, I have $remove which contains that bracketted list name
> > such as
> > 
> > [BLIND-HAMS] or any number of other names enclosed in brackets.
> > So, the next thing I do is to attempt to remove just that part of
> > the subject line, keeping everything else that was there.
> > 
> >$subject =~ s/'$remove'//;
> > print( $subject, "\n" );
> > 
> > The example, here is the closest thing to anything
> > happening.  In the case of [BLIND-HAMS] the B is gone but the
> > brackets and everything else remains
> > 
> > I looked around for examples of similar code and found
> > 
> > $subject =~ s/$remove\K.*?(?=\d+)//;
> > 
> > It looks like it should keep everything else in the $subject
> > string except [BLIND-HAMS] but it keeps everything including that
> > so there is no change.
> > 
> > I actually think I am close but the line with the
> > brackets may be confusing the shell although single and double
> > quotes don't make any difference.
> > 
> > I also may have damaged that last example when I modified
> > it to work with a string called $subject which is the whole
> > subject line and $remove which is the part I am trying to remove.
> > 
> > The rest of the script appears to work and is designed to
> > only list the first message in a list of N messages of the same
> > subject. so, if there are 120 messages with the subject of "how
> > did you spend your Summer?", I read the first of those subject
> > lines and none until the first message that doesn't have that
> > title.
> > 
> > Any constructive ideas are appreciated.  Thank you.
> > 
> > Martin McCormick
> > 
> > -- 
> > To unsubscribe, e-mail: beginners-unsubscr...@perl.org
> > For additional commands, e-mail: beginners-h...@perl.org
> > http://learn.perl.org/
> > 
> >   
> 
> I think it's because you have 
> 
> $subject =~ s/[BLIND-HAMS]//;
> 
> and it deletes first appeared symbol from the diapason.
> 

https://en.wiktionary.org/wiki/diapason - perhaps you mean "character class".

> You can try smth like $remove =~ s/([\[\]])/\\$1/g;
> 

Why not use http://perldoc.perl.org/functions/quotemeta.html ?

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Re: Removing a Pattern using a Regular Expression

[Shlomi Fish]

Hi,

On Wed, 13 Jun 2018 21:21:12 -0500
"Martin McCormick"  wrote:

> I wrote a small perl program to more quickly read all the
> subjects in an email list.  One of the things the script does is
> to remove the mailing list name which repeats for every message
> and consists of a [, some English text and finally a ].
> 
>   I was able to write a RE that identifies that text and
> cause the script to save that string in a variable called
> $remove.  That part works and looks like:
> 
> foreach my $field (@fields) {#Assemble the new subject.
> if($field =~ m/\[(.*?)\]/) 
> { #$field is the blocked field.
> $remove = $field;
> } #field is the blocked field.
> else
> { #$field is not the blocked string.
> $newest = $newest . $field;
> } #$field is not the blocked string.
> }#Assemble the new subject.
> 
> if ( $newest eq $previous ) {#Skip this iteration.
> $newest = "";
> next;
> }#Skip this iteration.
> else
> { #they are different.
> 

1. Your indentation is erratic.

2. See http://perl-begin.org/tutorials/bad-elements/ .


>   This is where things don't quite work yet.  At this
> point, I have $remove which contains that bracketted list name
> such as
> 
> [BLIND-HAMS] or any number of other names enclosed in brackets.
> So, the next thing I do is to attempt to remove just that part of
> the subject line, keeping everything else that was there.
> 
>$subject =~ s/'$remove'//;
> print( $subject, "\n" );
> 

1. why did you add single quotes?

2. Perhaps use
http://perl-begin.org/tutorials/bad-elements/#re_string_interpolate

>   The example, here is the closest thing to anything
> happening.  In the case of [BLIND-HAMS] the B is gone but the
> brackets and everything else remains
> 
>   I looked around for examples of similar code and found
> 
> $subject =~ s/$remove\K.*?(?=\d+)//;
> 
> It looks like it should keep everything else in the $subject
> string except [BLIND-HAMS] but it keeps everything including that
> so there is no change.
> 
>   I actually think I am close but the line with the
> brackets may be confusing the shell although single and double
> quotes don't make any difference.
> 
>   I also may have damaged that last example when I modified
> it to work with a string called $subject which is the whole
> subject line and $remove which is the part I am trying to remove.
> 
>   The rest of the script appears to work and is designed to
> only list the first message in a list of N messages of the same
> subject. so, if there are 120 messages with the subject of "how
> did you spend your Summer?", I read the first of those subject
> lines and none until the first message that doesn't have that
> title.
> 
> Any constructive ideas are appreciated.  Thank you.
> 
> Martin McCormick
> 



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Re: project euler #8

[Shlomi Fish]

Hi,

why did you resurrect a one year old's thread for which there were proper
replies here -
https://www.nntp.perl.org/group/perl.beginners/2017/05/msg126502.html and here
- https://github.com/shlomif/project-euler/tree/master/project-euler/8 . just
let sleeping dogs rest. Some comments on your code:

 On Wed, 06 Jun 2018 19:23:11 -0700
"John W. Krahn"  wrote:

> On Tue, 2017-05-16 at 14:01 +0800, derr...@thecopes.me wrote:
> 
> 
> I am working on problem #8 of the euler project. see below.
> > 
> > 
> > 
> > The four adjacent digits in the 1000-digit number that have the
> > greatest product are 9 × 9 × 8 × 9 = 5832.
> > 
> > 73167176531330624919225119674426574742355349194934
> > 96983520312774506326239578318016984801869478851843
> > 85861560789112949495459501737958331952853208805511
> > 12540698747158523863050715693290963295227443043557
> > 66896648950445244523161731856403098711121722383113
> > 6222989342338030813533627661428280686645238749
> > 30358907296290491560440772390713810515859307960866
> > 70172427121883998797908792274921901699720888093776
> > 65727333001053367881220235421809751254540594752243
> > 52584907711670556013604839586446706324415722155397
> > 53697817977846174064955149290862569321978468622482
> > 83972241375657056057490261407972968652414535100474
> > 82166370484403199890008895243450658541227588666881
> > 16427171479924442928230863465674813919123162824586
> > 17866458359124566529476545682848912883142607690042
> > 2421902267105562632109370544217506941658960408
> > 07198403850962455444362981230987879927244284909188
> > 84580156166097919133875499200524063689912560717606
> > 05886116467109405077541002256983155200055935729725
> > 71636269561882670428252483600823257530420752963450
> > 
> > Find the thirteen adjacent digits in the 1000-digit number that have
> > the greatest product. What is the value of this product?  
> 
> 
> 
> #!/usr/bin/perl
> use warnings;
> use strict;
> 
> ( my $x = < 73167176531330624919225119674426574742355349194934
> 96983520312774506326239578318016984801869478851843
> 85861560789112949495459501737958331952853208805511
> 12540698747158523863050715693290963295227443043557
> 66896648950445244523161731856403098711121722383113
> 6222989342338030813533627661428280686645238749
> 30358907296290491560440772390713810515859307960866
> 70172427121883998797908792274921901699720888093776
> 65727333001053367881220235421809751254540594752243
> 52584907711670556013604839586446706324415722155397
> 53697817977846174064955149290862569321978468622482
> 83972241375657056057490261407972968652414535100474
> 82166370484403199890008895243450658541227588666881
> 16427171479924442928230863465674813919123162824586
> 17866458359124566529476545682848912883142607690042
> 2421902267105562632109370544217506941658960408
> 07198403850962455444362981230987879927244284909188
> 84580156166097919133875499200524063689912560717606
> 05886116467109405077541002256983155200055935729725
> 71636269561882670428252483600823257530420752963450
> STUFF
> 
> my @z = ( 0 ) x 5;

why 5?
> while ( $x =~ / ( . ) (?= ( . ) ( . ) ( . ) ( . ) ( . ) ( . ) ( . ) ( .
> ) ( . ) ( . ) ( . ) ( . ) ) /xg ) {
> my $y = $1 * $2 * $3 * $4 * $5 * $6 * $7 * $8 * $9 * $10 * $11 *
> $12 * $13;
> @z = ( $1, $2, $3, $4, $5, $6, $7, $8, $9, $10, $11, $12, $13, $y )
> if $z[ -1 ] < $y;
> }
> 

this code is full of duplicate functionality and you are abusing the capture
vars as arrays.

The ?= trick is nice, though.

> print "@z\n";
> 
> 
> __END__
> 

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Re: can not locate installe module

[Shlomi Fish]

Hi,

On Mon, 4 Jun 2018 10:28:09 +0100
Gary Stainburn  wrote:

> On Monday 04 June 2018 09:36:02 Shlomi Fish wrote:
> > what does "perldoc -l MIME::Parser" say? Also see
> > http://perl-begin.org/FAQs/ and http://perl-begin.org/topics/cpan/ .  
> 
> I have tried this for all three modules installed through CPAN and all three 
> come up with the same thing:
> 
> [root@ollie2 ~]# perldoc -l MIME::Parser
> No documentation found for "MIME::Parser".
> [root@ollie2 ~]# perldoc -l Net::SCP
> No documentation found for "Net::SCP".
> [root@ollie2 ~]# perldoc -l Net::SSH
> No documentation found for "Net::SSH".
> [root@ollie2 ~]# 
> 
> If I try to find the perl modules it it looks like they haven't been 
> installed, but if that is the case, why does 'perl -c' come up OK?
> 

is there anything in https://en.wikipedia.org/wiki/Environment_variable ?
Perhaps you have https://metacpan.org/pod/local::lib enabled or similar.

> [root@ollie2 ~]# find / -iname Parser.pm
> /root/.cpan/build/MIME-tools-5.509-umkw_d/lib/MIME/Parser.pm
> /root/.cpan/build/MIME-tools-5.509-umkw_d/blib/lib/MIME/Parser.pm
> /root/ollie/root/.cpan/build/MIME-tools-5.427-bhvQQE/blib/lib/MIME/Parser.pm
> /root/ollie/root/.cpan/build/MIME-tools-5.427-bhvQQE/lib/MIME/Parser.pm
> /root/perl5/lib/perl5/MIME/Parser.pm

Looks like it isn't installed system-wide - only under the "/root" home dir.

> /usr/lib64/perl5/vendor_perl/XML/Parser.pm
> /usr/lib64/perl5/vendor_perl/HTML/Parser.pm
> /usr/share/perl5/vendor_perl/TAP/Parser.pm
> /usr/share/perl5/vendor_perl/Mail/SpamAssassin/Conf/Parser.pm
> /usr/share/perl5/vendor_perl/Convert/ASN1/parser.pm
> [root@ollie2 ~]# find / -iname SCP.pm
> /root/.cpan/build/Net-SCP-0.08-q8mDLD/SCP.pm
> /root/.cpan/build/Net-SCP-0.08-q8mDLD/blib/lib/Net/SCP.pm
> /root/perl5/lib/perl5/Net/SCP.pm
> [root@ollie2 ~]# 
> 



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Re: difficulty with matching

[Shlomi Fish]

On Sat, 2 Jun 2018 07:30:48 -0500
p...@reason.net wrote:

> Very useful advice, Shlomi; thanks!
> 

you are welcome! Also see http://perl-begin.org/tutorials/bad-elements/ , which
I also maintain.

> 
> > On Jun 2, 2018, at 3:57 AM, Shlomi Fish  wrote:
> > 
> > On Fri, 1 Jun 2018 15:54:55 -0500
> > Rick T mailto:p...@reason.net>> wrote:
> >   
> >> This is a newbie question, I’m sure. But I get perplexed easily!
> >> 
> >> The follow code segment expects to receive a $student_id consisting of a
> >> surname followed by a hyphen followed by a number. The die is for testing
> >> what I’m doing. 
> >> 
> >> If I feed it 'jones-123’ it dies with ‘jones, - , 123’ as I expected. But
> >> if I feed it ‘jones-‘ omitting the number on the end, it dies with no
> >> matches at all (or blanks): ‘ , , ‘ and I cannot figure out why it does
> >> not die with ‘jones, -, ' and would appreciate an explanation. Many thanks!
> >> 
> >>$student_id = lc $student_info_hash{student_id}; # Impose lower case
> >>$student_id =~ s/\s//xmsg;   # Remove whitespace
> >> 
> >>$student_id =~
> >>m{
> >>\A([a-z]+)  # match and capture leading alphabetics 
> >>(-) # hyphen to separate surname from student number
> >>([0-9]+\z)  # match and capture trailing digits
> >> }xms;  # Perl Best Practices
> >>$student_surname = $1;
> >>my $hyphen   = $2;
> >>$student_number  = $3;  
> > 
> > In addition to the other comments, Instead of that, you should do:
> > 
> > if (my ($surname, $hyphen, $num) = $student_id =~ m{ ... }xms)
> > {
> > # match successful.
> > }
> > else
> > {
> > die "match failed ...";
> > }
> > 
> > always check for regex match successes and use the return captures of regex
> > ops. See PBP for more.
> >   
> >> die "$student_surname, $hyphen, $student_number”;
> >> 
> >> Rick Triplett
> >>   
> > 
> > 
> > 
> > -- 
> > -
> > Shlomi Fish   http://www.shlomifish.org/ <http://www.shlomifish.org/>
> > Best Introductory Programming Language - http://shlom.in/intro-lang
> > <http://shlom.in/intro-lang>
> > 
> > A horse! A horse! My kingdom for a horse!
> >— https://en.wikiquote.org/wiki/Richard_III_%28play%29
> > <https://en.wikiquote.org/wiki/Richard_III_%28play%29>
> > 
> > Please reply to list if it's a mailing list post - http://shlom.in/reply
> > <http://shlom.in/reply> .
> > 
> > --
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Re: can not locate installe module

[Shlomi Fish]

Hi,

On Mon, 4 Jun 2018 07:55:16 +0100
Gary Stainburn  wrote:

> I've juts built a new Centos 7 email server and all has gone well.
> 
> I have used RPM's where possible, but for some modules I have had to use
> CPAN. One such module was MIME::Parser, which installed without errors.
> 
> If I check my program it now says that it's fine.  If I try to re-install the 
> module it says it's up to date.
> 
> however, when I try to run the program (as a pipe via exim) it complains that 
> it cannot locate the module.
> 
>  Does anyone have any ideas?
> 
> 
> cpan[1]> install MIME::Parser  
> Reading '/root/.cpan/Metadata'
>   Database was generated on Sun, 03 Jun 2018 04:17:03 GMT
> MIME::Parser is up to date (5.509).
> 
> cpan[2]> Lockfile removed.  
> [root@ollie2 ~]# perl -c /etc/exim/bin/admin_doc_gateway4
> /etc/exim/bin/admin_doc_gateway4 syntax OK
> [root@ollie2 ~]# 
> 
> 
> -- pipe to |/etc/exim/bin/admin_doc_gateway4 -e >>/var/log/faxgateway 2>&1
>        generated by dealpa...@ringways.co.uk --
> 
> Can't locate MIME/Parser.pm in @INC (@INC 
> contains: /usr/local/lib64/perl5 /usr/local/share/perl5 
> /usr/lib64/perl5/vendor_perl /usr/share/perl5/vendor_perl /usr/lib64/perl5 
> /usr/share/perl5 .) 
> at /etc/exim/bin/admin_doc_gateway4 line 9.
> BEGIN failed--compilation aborted at /etc/exim/bin/admin_doc_gateway4 line 9.
> 

what does "perldoc -l MIME::Parser" say? Also see http://perl-begin.org/FAQs/
and http://perl-begin.org/topics/cpan/ .

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Re: difficulty with matching

[Shlomi Fish]

On Fri, 1 Jun 2018 15:54:55 -0500
Rick T  wrote:

> This is a newbie question, I’m sure. But I get perplexed easily!
> 
> The follow code segment expects to receive a $student_id consisting of a
> surname followed by a hyphen followed by a number. The die is for testing
> what I’m doing. 
> 
> If I feed it 'jones-123’ it dies with ‘jones, - , 123’ as I expected. But if
> I feed it ‘jones-‘ omitting the number on the end, it dies with no matches at
> all (or blanks): ‘ , , ‘ and I cannot figure out why it does not die with
> ‘jones, -, ' and would appreciate an explanation. Many thanks!
> 
> $student_id = lc $student_info_hash{student_id}; # Impose lower case
> $student_id =~ s/\s//xmsg;   # Remove whitespace
> 
> $student_id =~
> m{
> \A([a-z]+)  # match and capture leading alphabetics 
> (-) # hyphen to separate surname from student number
> ([0-9]+\z)  # match and capture trailing digits
>  }xms;  # Perl Best Practices
> $student_surname = $1;
> my $hyphen   = $2;
> $student_number  = $3;

In addition to the other comments, Instead of that, you should do:

if (my ($surname, $hyphen, $num) = $student_id =~ m{ ... }xms)
{
# match successful.
}
else
{
die "match failed ...";
}

always check for regex match successes and use the return captures of regex
ops. See PBP for more.

> die "$student_surname, $hyphen, $student_number”;
> 
> Rick Triplett
> 



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Re: Read a huge text file in perl

[Shlomi Fish]

Hi,

On Thu, 24 May 2018 20:27:23 +0530
SATYABRATA KARAN <satyabratakara...@gmail.com> wrote:

> Hello,
> Does anyone guide me how to handle a huge file (>50GB) in perl?
> 
> I tried open method this way, but it's hanging the terminal. I think that
> is out of memory error internally.
> 
> open my $FILE, "<", "Log_file.txt";
> 
> while (<$FILE>) {
>  chomp;
>  some task;
>  ...
> }
> 
> close $FILE;
>

1. How long are the lines in the file?

2. Can you try https://en.wikipedia.org/wiki/Htop or similar to be sure?

 
> 
> Thanks,
> Satya



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Re: regex with HEX ascii chars

[Shlomi Fish]

On Thu, 12 Apr 2018 17:26:57 +0100
Gary Stainburn <gary.stainb...@ringways.co.uk> wrote:

> I have a text file (created by  pdftotext) that I've imported into my script.
> 
> It contains ASCII characters 251 for crosses and 252 for ticks.  If I load
> the file in gvim and do :as
> 
> it reports the characters as 
> 
>  251, Hex 00fb, Octal 373
>  252, hex 00fc, Octal 374
> 
> However, when I try to seacch for it using
> 
> if ($line=~/[\xfb|\xfc]/) {
> 
> or even just 
> 
> if ($line=~/\xfb/) { 
> 
> it always fails.  What am I doing wrong?
> 

Perhaps see http://perldoc.perl.org/perlunitut.html - you may need to read the
file as binary or iso8859-1 or whatever. Also see
https://github.com/shlomif/how-to-share-code-online and read what Andy noted.

> Gary
> 



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Re: Syntax problem

[Shlomi Fish]

Hi,

On Wed, 28 Mar 2018 13:00:47 +0700
Olivier <olivier.nic...@cs.ait.ac.th> wrote:

> Hi,
> 
> I am building a script to modify my LDAP directory and I want to use
> something like:
> 
> $mesg = $ldap->modify( $dn,
>   replace => {
> description => 'New List of members',
> seeAlso => 'Some reference'
>   }
> );
> 
> But I would like to build the list of replacements dynamically, that is,
> have a variable of the appropriate type, where I can first store
> "description" and "New List of members" then also store "seeAlso" and
> "Some reference"; and then only use that variable to do the replace.
> 

please see http://perl-begin.org/topics/references/ .

> I have two questions:
> 
> - What type should I use for the variable?
> 
> - What will be the syntax for the $ldap->modify statement?
> 
> Thanks in advance,
> 
> Olivier
> 
> 
> 



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Re: [^/]* Is Not Working

[Shlomi Fish]

On Sun, 18 Mar 2018 12:32:44 +0100
hw <h...@adminart.net> wrote:

> John SJ Anderson <j...@genehack.org> writes:
> 
> >> But this one in its place does not work:
> >> if ($link =~ m/\/([^/]*)$/) { # Oddly this does not work  
> >
> > You still need to escape the `/` inside the character class.
> >
> > This works in my testing: `m/\/([^\/]*)$/`.
> >
> > IMO this is a case where an alternative delimiter for `m//` — such as the
> > `#` in your working example — is a better approach.   
> 
> IIRC it´s said in best practises or so that brackets ({, }) should be
> used for an alternative delimiter and that they should probably be the
> only substitute to use.
> 

I don't blindly follow https://en.wikipedia.org/wiki/Perl_Best_Practices and
disagree about this. I find it useful to use #, % and other delimiters which do
not naturally occur in regexes or otherwise.


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Re: Help debugging some old Bugzilla perl scripts

[Shlomi Fish]

Hi jose,

please see http://www.shlomifish.org/Files/files/code/bugzilla.patch for my
patch against bugzilla 3.2 to get it to compile with recent perls.

 On Mon, 26 Feb 2018 05:43:45 +0100
"jose cabrera"  wrote:

> On Sunday, February 25, 2018 at 11:26 PM, "Uri Guttman" wrote...
> > >
> > > 
> > > syntax error at Bugzilla/Bug.pm line 1085, near "$type qw(dependson
> > > blocked)"
> > >
> > > Here is line 1085:
> > >  foreach my $type qw(dependson blocked) {
> > >  my @bug_ids = split(/[\s,]+/, $deps_in{$type});  
> > 
> > put parens around the qw(). it used to be allowed as the () in the for 
> > loop but not anymore.  
> 
> Thanks.
> 
> > >
> > > 
> > > Can't use global @_ in "my" at Bugzilla/Bug.pm line 1134, near "= @_"
> > >
> > > Here is line 1133, 1134, 1135:
> > > sub _check_dup_id {
> > >  my ($self, $dupe_of) = @_;
> > >  my $dbh = Bugzilla->dbh;
> > >  
> 
> Yeah, I could not see anything wrong with it, but what I did was to install
> perlbrew and I am downloading 5.8.9, which should be the version that was
> released with Bugzilla 3.2.  I am going to see if this new change fixes all
> of these errors. ;-)  Thanks for the support.
> 
> josé
> 
> --
> What if eternity is real? Where will you spend it? Hmmm...
> 

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Re: Does perl v5.8.9 supports Ubuntu 64 bit?

[Shlomi Fish]

Hi jose,

On Mon, 26 Feb 2018 05:56:19 +0100
"jose cabrera"  wrote:

> Greetings!
> 
> I just installed perlbrew and I tried installing perl v5.8.9 to prevent
> trying to fix a bunch of v5.8.9 perl code, but it failed.  The first thing
> that came to mind was x64 vs x32.  Can this perl version v5.8.9 be installed
> on an Ubuntu x64 bit?  Thansk.
> 

were the only failing tests in op/numconvert? If so, it does not seem serious.
and you can use --force or --notest. That put aside, this is an old version of
perl with many known bugs that have been fixed in later versions and many
missing features. Please don't use it.

> josé
> 
> --
> What if eternity is real? Where will you spend it? Hmmm...
> 

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Re: ssh::command

[Shlomi Fish]

Hi Lancelot,

some comments on your code:

On Tue, 13 Feb 2018 17:19:03 +0800
Lancelot Mak <lancelot@computer.org> wrote:

> #!/usr/bin/perl -W
> 

1. don't use -w - http://perl-begin.org/tutorials/bad-elements/#the-dash-w-flag

2. use strict and warnings instead.

> use SSH::Command;
> 
> $cmdln = `grep $ARGV[0] list.txt`;
> chomp($cmdln);

use file i/o or IO-All or Path-Tiny instead of ``:
http://perl-begin.org/tutorials/bad-elements/#calling-the-shell-too-much

> ($cmdhost,$user,$pass) = split(':',$cmdln);
> $p = `echo $pass|base64 -d`;
> chomp($p);
> 

use https://metacpan.org/release/MIME-Base64 instead and avoid people snooping
on ps.
> $cmdlog = ssh_execute(
> host => $cmdhost,
> username => $user,
> password => $p,
> command => "$ARGV[1]",
> );
> 

See http://perl-begin.org/tutorials/bad-elements/#vars_in_quotes .

> 
> print $cmdlog;
> 
> print "\n";
> 
> 
> On 13 February 2018 at 16:36, Chas. Owens <chas.ow...@gmail.com> wrote:
> 
> > Can you simplify your code to a short program that had the issue and post
> > it? Often the act of shortening the program reveals the problem on its own.
> >
> > On Mon, Feb 12, 2018, 22:37 Lancelot Mak <lancelot@gmail.com> wrote:
> >  
> >> Hi all,
> >> I am using SSH::Command module to do ssh stuff but it does not return
> >> full reply from server. Any clue? It just returns part of it. Is it
> >> timeout? or what?
> >> Thanks.
> >>
> >>
> >> --
> >> --
> >> Lancelot Mak
> >>  
> >  
> 
> 



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Re: Checking if a website is up doesn't work correctly

[Shlomi Fish]

Hi Manfred!

On Tue, 13 Feb 2018 12:25:31 +0100
Manfred Lotz <ml_n...@posteo.de> wrote:

> Hi there,
> Somewhere I found an example how to check if a website is up.
> 
> Here my sample:
> 
> #! /usr/bin/perl
> 
> use strict;
> 
> use LWP::Simple;
> my $url="https://notabug.org;;
> if (! head($url)) {
> die "$url is DOWN" 
> }
> 
> Running above code I get
>   https://notabug.org is DOWN at ./check_url.pl line 8.
> 

This code seems to work fine here:

#!/usr/bin/perl

use strict;
use warnings;

use LWP::Simple;
  my $url="https://shlomif.github.io/;;
# my $url="https://notabug.org/;;
if (! head($url)) {
die "$url is DOWN";
}

seems like notabug blocks libwww-perl.


> 
> However, firefox shows the site works ok.
>

same here.

Regards,

Shlomi
 
> 
> What am I doing wrong?
> 
> 



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Re: What is the substitute for $#?

[Shlomi Fish]

Hi Peng,

On Fri, 26 Jan 2018 15:33:43 -0600
Peng Yu <pengyu...@gmail.com> wrote:

> Hi, $# is deprecated. Could anybody let me know what is the substitute for it?
> 
> https://perldoc.perl.org/perlvar.html
> 
> $# was a variable that could be used to format printed numbers. After
> a deprecation cycle, its magic was removed in Perl v5.10.0 and using
> it now triggers a warning: $# is no longer supported.
> 

according to
https://metacpan.org/pod/release/NWCLARK/perl-5.8.3/pod/perlvar.pod - it seems
it used printf/sprintf format so just use those explicitly where needed. See:

* http://perldoc.perl.org/functions/sprintf.html

* http://perl-begin.org/uses/text-generation/

e.g:

print "I am ", sprintf("%e", $age), " years old.";

Regards,

Shlomi
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Re: Find::Perl find not returning

[Shlomi Fish]

{resending}

Hi Mike,

On Wed, 13 Dec 2017 11:28:55 +
Mike Martin  wrote:

> Hi
> I have the following code
> 
> use strict;
> use File::Find;
> my @vsbe;
> my $top='P:\PT-6\PT-60\PT-603\Shared\Data Store\Files Dump Folder';
> my $max_depth=9;
> my $cnt1=0;
> 
> find({wanted=>\,preprocess=>\},$top) ;  
> 
> sub wanted1 {
> 
> if ($cnt1 <=1000){
> my $file = $File::Find::name;
> if (grep {/vsb$/} $file){
> push @vsbe, $file if $cnt1 <=1000 ;
> $cnt1++;
> print $cnt1,"\n" ;
> }
> else {return}
> 
> return if $cnt1 >=1000
> }
> return
> 
> }
> sub preprocess1 {
> my $depth = $File::Find::dir =~ tr[\\][];
> #print 'depth',"\t",$depth,"\t",$File::Find::dir,"\n";
> return  @_ if $depth < $max_depth;
> return grep { not -d } @_ if $depth == $max_depth;
> return;
> }
> 
> Unfortunately the wanted function never returns, it (at best) stays stuck
> on print the last value of $cnt1 (1000)
> 
> Any ideas what is happening here

my guess based on reading your code is that File::Find continues to scan the
directory tree recursively and calling wanted1() for every file. This is one of
the design quirks of the F::F interface and I suggest looking at better
alternatives on CPAN, such as
http://www.shlomifish.org/open-source/projects/File-Find-Object/ which I
maintain. See https://shlomif-tech.livejournal.com/29315.html for an article I
wrote about some other philosophical limitations of F::F that I solve (one of
them is similar to your use case).

Regards,

Shlomi

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Re: Find::Perl find not returning

[Shlomi Fish]

Hi Mike,

On Wed, 13 Dec 2017 11:28:55 +
Mike Martin <redt...@gmail.com> wrote:

> Hi
> I have the following code
> 
> use strict;
> use File::Find;
> my @vsbe;
> my $top='P:\PT-6\PT-60\PT-603\Shared\Data Store\Files Dump Folder';
> my $max_depth=9;
> my $cnt1=0;
> 
> find({wanted=>\,preprocess=>\},$top) ;  
> 
> sub wanted1 {
> 
> if ($cnt1 <=1000){
> my $file = $File::Find::name;
> if (grep {/vsb$/} $file){
> push @vsbe, $file if $cnt1 <=1000 ;
> $cnt1++;
> print $cnt1,"\n" ;
> }
> else {return}
> 
> return if $cnt1 >=1000
> }
> return
> 
> }
> sub preprocess1 {
> my $depth = $File::Find::dir =~ tr[\\][];
> #print 'depth',"\t",$depth,"\t",$File::Find::dir,"\n";
> return  @_ if $depth < $max_depth;
> return grep { not -d } @_ if $depth == $max_depth;
> return;
> }
> 
> Unfortunately the wanted function never returns, it (at best) stays stuck
> on print the last value of $cnt1 (1000)
> 
> Any ideas what is happening here

my guess based on reading your code is that File::Find continues to scan the
directory tree recursively and calling wanted1() for every file. This is one of
the design quirks of the F::F interface and I suggest looking at better
alternatives on CPAN, such as
http://www.shlomifish.org/open-source/projects/File-Find-Object/ which I
maintain. See https://shlomif-tech.livejournal.com/29315.html for an article I
wrote about some other philosophical limitations of F::F that I solve (one of
them is similar to your use case).

Regards,

Shlomi

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Re: perlbrew and modules

[Shlomi Fish]

On Thu, 7 Dec 2017 12:44:51 -0800
SSC_perl <p...@surfshopcart.com> wrote:

> > On Dec 7, 2017, at 12:04 PM, Shlomi Fish <shlo...@shlomifish.org> wrote:
> > 
> > What does:
> > 
> > say "@INC";
> > 
> > say if you add it to the script?  
> 
>   I get:
> 
> /home/user/perl5/perlbrew/perls/perl-5.26.1/lib/site_perl/5.26.1/x86_64-linux
> /home/user/perl5/perlbrew/perls/perl-5.26.1/lib/site_perl/5.26.1
> /home/user/perl5/perlbrew/perls/perl-5.26.1/lib/5.26.1/x86_64-linux
> /home/user/perl5/perlbrew/perls/perl-5.26.1/lib/5.26.1
> 
>   I found a .cpanm directory in /home/user where all the modules are
> being installed.  Could that have anything to do with it?  I tried adding
> that directory with "use lib" but I still get the 500 error.
> 

you should make sure that the modules you wish to use are in one of the
dirs in @INC. cpanm should install to  the global directories.

> Thanks,
> Frank



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Re: perlbrew and modules

[Shlomi Fish]

On Thu, 7 Dec 2017 11:50:17 -0800
SSC_perl <p...@surfshopcart.com> wrote:

>   I've run into another strange problem that I don't understand.
> Running the script below produces the output "Perl v5.26.1".  However, if I
> add the line: use CGI::Carp qw(fatalsToBrowser);  it produces a 500 error.
> 
>   On the shared server, this worked as it should, with
> 'fatalsToBrowser' showing any errors.  But the VPS is just backwards - adding
> it crashes the script!  This actually happens with any module and, yes, they
> are installed:
> 
> > cpanm install CGI::Carp  
> install is up to date. (0.01)
> CGI::Carp is up to date. (4.38)
> 
>   I have been fighting with this VPS setup for almost 2 weeks now just
> to get a functioning modern Perl environment and I'm about at my wits end.
> It shouldn't be this hard.
> 
>   I'd appreciate any help.
> 
> Thanks,
> Frank
> 
> 
> 
> 
> #!/home/user/perl5/perlbrew/perls/latest/bin/perl
> 
> use v5.26;
> use warnings;
> use diagnostics;
> 
> print "Content-type: text/html\n\n";
> say 'Perl '. $^V;

Hi Frank!

What does:

    say "@INC";

say if you add it to the script?


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Re: [OT] converting a script to a distribution

[Shlomi Fish]

Hi Luca,

On Wed, 29 Nov 2017 13:56:48 +0100
Luca Ferrari <fluca1...@infinito.it> wrote:

> Hi all,
> This is not quite tied to Perl itself, but I'm trying to migrate a few
> stand-alone scripts I've written to fully distributions, may be
> uploaded to CPAN.
> Now, using a tool like distzilla, or alike, and assuming each script
> has already its git story and configuration files laying around, what
> is the better way to start at? Any pointer?

See http://perl-begin.org/topics/cpan/ and also read about modulinos -
https://duckduckgo.com/?q=perl+modulino=web . There is also
App::Cmd https://metacpan.org/search?q=app%20cmd and similar modules.

> 
> Thanks,
> Luca
> 



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Rindolf is the Evil twin brother of Rudolph and Randolph, Santa’s goody-two-
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Re: Using Pack and Unpack

[Shlomi Fish]

On Wed, 06 Dec 2017 21:53:37 -0600
"Martin McCormick" <marti...@suddenlink.net> wrote:

> A perl program needs to send binary data to an external device
> such that 0xff looks like 
> 
>   I have a line in the program as follows:
> 
> my $txstart = pack("h*","fefe5a95");
> 
> Are those 4 bytes usable as the binary data 
> 
> fe fe 5a 95?
> 
>   Is there a good way when running perl -d to view the
> contents of the string to make sure it is what it should be?
> 

Yes, see the "x" command
( http://perl-begin.org/tutorials/perl-for-newbies/part2/#page--debugger--DIR ),
https://metacpan.org/pod/Data::Dumper , https://metacpan.org/pod/DDP , and some
debugger GUIs such as https://en.wikipedia.org/wiki/Data_Display_Debugger .

Regards,

Shlomi

> Thank you.
> 
> Martin McCormick
> 



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Re: Getting the results of a remote script

[Shlomi Fish]

Hi Gary,

On Fri, 10 Nov 2017 09:48:30 +
Gary Stainburn <gary.stainb...@ringways.co.uk> wrote:

> On Friday 10 November 2017 00:08:09 SSC_perl wrote:
> > > On Nov 9, 2017, at 2:06 PM, David Precious <dav...@preshweb.co.uk> wrote:
> > >
> > > you'll get whatever the script output to STDOUT.  
> >
> > Thanks a million, Dave!  STDOUT was what I was missing.  I've never
> > used that before, so this was news to me.  The remote script now returns a
> > string that I can manipulate and use in the local script.
> >
> > Thanks again,
> > Frank  
> 
> I would also look at using JSON for anything other than simple examples.  I 
> use this technique extensively for custom peer-to-peer apps. 
> 
> I have even develope a small xinetd service to accept incoming connections.
> 
> This has then enabled me to use Net::telnet in client scripts to generate 
> interactive services. JSON is a good, consistent method of transferring
> data.

While I agree, see http://seriot.ch/parsing_json.php for a roundup of security
problems and inconsistencies in JSON parsers.

>It also helps when combining PERL and PHP apps
> 

"Perl" is not an acronym - see
http://perl-begin.org/learn/Perl-perl-but-not-PERL/ and
https://github.com/perl-doc-cats/perlfaq/blob/master/lib/perlfaq1.pod#whats-the-difference-between-perl-and-perl
 .

Regards,

Shlomi

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Re: Getting the results of a remote script

[Shlomi Fish]

On Thu, 9 Nov 2017 08:16:47 +0700
thelip sia <hei...@gmail.com> wrote:

> you can use backtick to store the output.
> $list = `ssh usern...@domain.com '/usr/bin/perl /cgi-bin/dir-list.pl'`;
> 

Indeed, but note that one should be careful when interpolating strings there:

* http://perl-begin.org/topics/security/code-markup-injection/

* https://metacpan.org/pod/String::ShellQuote

Also see
http://perl-begin.org/tutorials/bad-elements/#declaring_all_vars_at_top
regarding predeclaration.


> Regards,
> Heince
> 
> On Thu, Nov 9, 2017 at 7:15 AM, SSC_perl <p...@surfshopcart.com> wrote:
> 
> > I have a script on a remote server that creates a list of all
> > directories on the server that end in a dash.  I need that list on my
> > laptop.  Is it possible to get the result into a variable in my local
> > script by triggering the remote script via ssh?  I've tried this:
> >
> > $list = system('ssh usern...@domain.com '/usr/bin/perl /cgi-bin/
> > dir-list.pl'");
> >
> > but it just returns '0'.  The system call is working fine - I just can't
> > get the result returned in $list.
> >
> > Searching hasn't returned an answer.  Is there another way to get
> > what I'm after?
> >
> > Thanks,
> > Frank
> > --
> > To unsubscribe, e-mail: beginners-unsubscr...@perl.org
> > For additional commands, e-mail: beginners-h...@perl.org
> > http://learn.perl.org/
> >
> >
> >  



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At this point, I'd like to take a moment to speak to you about the Adobe PSD
format. PSD is not a good format. PSD is not even a bad format. Calling it
such would be an insult to other bad formats, such as PCX or JPEG. No, PSD is
an abysmal format.
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Re: Warnings::Unused Linux perl

[Shlomi Fish]

Hi,

On Sun, 05 Nov 2017 18:21:25 -0600
"Martin McCormick" <marti...@suddenlink.net> wrote:

> Shlomi Fish <shlo...@shlomifish.org> writes:
> > Hi Martin,
> > 
> > please see https://metacpan.org/release/warnings-unused as well as
> > http://perl-begin.org/topics/cpan/wrappers-for-distributions/ and
> > http://perl-begin.org/topics/cpan/ . It should not be hard to install and 
> > your
> > Linux distro may already have it packaged. It is just that it was already
> > available on your FBSD system.  
> 
>   Thank you.  I will give these a try as I thought the
> same functionality might be there in a module by another name
> when cpanp -i basically said it couldn't find anything by that
> name.
> 

The problem may have been the https://en.wikipedia.org/wiki/Letter_case . That
module has no uppercase letters.

> Martin
> 



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Re: Warnings::Unused Linux perl

[Shlomi Fish]

On Sun, 05 Nov 2017 16:51:09 -0600
"Martin McCormick" <marti...@suddenlink.net> wrote:

> Most of the work I did in perl was on a FreeBSD system and not
> surprisingly, perl under Linux behaves essentially the same but
> one thing I notice is that Warnings::Unused doesn't appear as a
> module.  It is quite useful in keeping one's code free of clutter
> so the question is whether there is another module that performs
> the same task?
> 
> use Warnings::Unused
> 
> in code produces:
> 
> Can't locate warnings/unused.pm in @INC (@INC
> contains: /etc/perl /usr/local/lib/perl/5.14.2 /usr/local/share/perl/5.14.2 
> /usr/lib/perl5 /usr/share/perl5 /usr/lib/perl/5.14 /usr/share/perl/5.14 
> /usr/local/lib/site_perl .)
> at ./232start line 3. Thank you.
> 
> Martin McCormick
> 

Hi Martin,

please see https://metacpan.org/release/warnings-unused as well as
http://perl-begin.org/topics/cpan/wrappers-for-distributions/ and
http://perl-begin.org/topics/cpan/ . It should not be hard to install and your
Linux distro may already have it packaged. It is just that it was already
available on your FBSD system.




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Re: Archive::Zip->addTree returned 2

[Shlomi Fish]

On Wed, 4 Oct 2017 23:26:31 +0530
Asad  wrote:

> Hi All
> 
> I have perl script abc.pl and module abc.pm . When i execute abc.pl which
> is using one the modules
> 

Hi Asad!

Please see https://github.com/shlomif/how-to-share-code-online and comply with
the instructions there.



> Archive::Zip > I am getting the following errors :
> 
> patch_zip: /Location/patch1//patch1.zip Creating zip file
> /Location/patch1//patch1.zip for apply pwd: The file access
> permissions do not allow the specified action. A process terminated prior
> to completion. pwd: The file access permissions do not allow the specified
> action. pwd: The file access permissions do not allow the specified action.
> error: undef returned by _untaintDir on cwd at
> /Location/lib/Archive/Zip/Archive.pm line 754
> Archive::Zip::Archive::addTree('Archive::Zip::Archive=HASH(0x1113ceee8)',
> '/Location/patch1//')
> 
> 
> Seems to me a permission issue but unable to identify what permission issue
> is there if the Filesystem or directory underneath it .
> 
> How to identify .

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Re: do something when using Gtk3

[Shlomi Fish]

On Tue, 05 Sep 2017 04:24:31 +0200
hw <h...@adminart.net> wrote:

> Shlomi Fish <shlo...@shlomifish.org> writes:
> 
> > Hi hw,
> >  
> > On Mon, 28 Aug 2017 04:54:04 +0200
> > hw <h...@adminart.net> wrote:
> >  
> >> Hi,
> >> 
> >> when writing a program that uses Gtk3, how can I make it so that the
> >> program does something at regular time intervals?
> >>   
> >
> > This DDG search - https://duckduckgo.com/?q=gtk3+timer=qa - has some
> > relevant results including
> > https://stackoverflow.com/questions/8352027/gtk-timer-how-to-make-a-timer-within-a-frame
> >  .
> > There are examples for using it in Perl in t/9.t here -
> > https://git.gnome.org//browse/perl-Glib .  
> 
> Thanks, at least this some indication that it might be possible.  Now I
> need to figure out how to use it with a perl program that uses gtk3 ...
> 

You're welcome!

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Re: do something when using Gtk3

[Shlomi Fish]

Hi hw,
 
On Mon, 28 Aug 2017 04:54:04 +0200
hw <h...@adminart.net> wrote:

> Hi,
> 
> when writing a program that uses Gtk3, how can I make it so that the
> program does something at regular time intervals?
> 

This DDG search - https://duckduckgo.com/?q=gtk3+timer=qa - has some
relevant results including
https://stackoverflow.com/questions/8352027/gtk-timer-how-to-make-a-timer-within-a-frame
 .
There are examples for using it in Perl in t/9.t here -
https://git.gnome.org//browse/perl-Glib .

Hope it helps!

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Re: perl -e 'my $i = 0; $i = defined($i) ? (!!$i) : 0; print "i: $i\n";'

[Shlomi Fish]

Hi hw!

Please see
http://www.shlomifish.org/philosophy/computers/netiquette/email/reply-to-list.html
.

On Sat, 1 Jul 2017 19:15:22 +0200 hw <h...@gc-24.de> wrote:

> Shlomi Fish wrote:
> > Hi Shawn!
> >
> > On Sat, 1 Jul 2017 11:32:30 -0400
> > Shawn H Corey <shawnhco...@gmail.com> wrote:
> >  
> >> On Sat, 1 Jul 2017 17:27:02 +0200
> >> hw <h...@gc-24.de> wrote:
> >>  
> >>>
> >>> Hi,
> >>>
> >>> can someone please explain this:
> >>>
> >>>
> >>> perl -e 'my $i = 0; $i = defined($i) ? (!!$i) : 0; print "i: $i\n";'
> >>> i:
> >>>
> >>>
> >>> Particularly:
> >>>
> >>>
> >>> + Why doesn´t it print 1?  
> >>
> >> Because !!$i is zero
> >>  
> >>>
> >>> + How is this not a bug?  
> >>
> >> Nope, no bug.
> >>  
> >>>
> >>> + What is being printed here?  
> >>
> >> !!$i which is !(!(0)) which is !(1) which is 0
> >>  
> >
> > I suspect !1 returns an empty string in scalar context.  
> 
> What would be the reasoning for a numerical operator turning
> numerical values into (empty) strings within a numerical context?
> 

"!" is not a numerical operator - it is a *logical* operator. If one passes a
true value to it one gets a false value. Else, one gets a true value. See
http://perldoc.perl.org/perlop.html . If used in a numerical context, false
values are treated as zeroes, but not all of them are zeroes in other contexts.

Regards,

Shlomi


> 
> 
> >  
> >>>
> >>> + How do you do what I intended in perl?
> >>>  
> >>
> >> How do we know what you intend?
> >>
> >>  
> >
> >
> >  
> 



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Re: perl -e 'my $i = 0; $i = defined($i) ? (!!$i) : 0; print "i: $i\n";'

[Shlomi Fish]

Hi Shawn!

On Sat, 1 Jul 2017 11:32:30 -0400
Shawn H Corey <shawnhco...@gmail.com> wrote:

> On Sat, 1 Jul 2017 17:27:02 +0200
> hw <h...@gc-24.de> wrote:
> 
> > 
> > Hi,
> > 
> > can someone please explain this:
> > 
> > 
> > perl -e 'my $i = 0; $i = defined($i) ? (!!$i) : 0; print "i: $i\n";'
> > i:
> > 
> > 
> > Particularly:
> > 
> > 
> > + Why doesn´t it print 1?  
> 
> Because !!$i is zero
> 
> > 
> > + How is this not a bug?  
> 
> Nope, no bug.
> 
> > 
> > + What is being printed here?  
> 
> !!$i which is !(!(0)) which is !(1) which is 0
> 

I suspect !1 returns an empty string in scalar context.

> > 
> > + How do you do what I intended in perl?
> >   
> 
> How do we know what you intend?
> 
> 



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I don’t believe in fairies. Oops! Another fairy died.
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Re: Confused with File::Find

[Shlomi Fish]

Hi Harry!

On Fri, 23 Jun 2017 16:56:13 -0400
Harry Putnam <rea...@newsguy.com> wrote:

> Trying for a better understand of using File::Find, butI'm missing
> something pretty basic I think
> 
> First: The directory structure in this test:
> 
> ./one/tst.pl
> two/tst.pl
>   three/tst.pl
> 
> So each directory in the layering has the same type -f file in it.
> 
> Or
>   ls -R ./one
>   ./one:
>   tst.pl  two
> 
>   ./one/two:
>   three  tst.pl
> 
>   ./one/two/three:
>   tst.pl
> 
> I'm sure its something in my formulation (in other words, pilot
> shooting self in foot) but; This bit of code seems not to do what one
> would expect:
> 
> ---   ---   ---=---   ---   ---
> 
>   use strict;
>   use warnings;
>   use File::Find;
> 
>   my $d = './one';
> 
>   find sub {
> return if -f;
> print "\$File::Find::dir<$File::Find::dir>\n";
>   }, $d;
> 
> ---   ---   ---=---   ---   --- 
> 
> Output:
>   reader > ./tst.pl
>   $File::Find::dir<./one>
>   $File::Find::dir<./one>
>   $File::Find::dir<./one/two>
> 

$File::Find::dir is the containing directory of the path item (= the dirname in
http://perldoc.perl.org/File/Basename.html ). Finally, note that File::Find has
some severe philosophical limitations, and you should look into alternatives on
CPAN such as https://metacpan.org/pod/File::Find::Object (which I happen to
maintain) or https://metacpan.org/pod/Path::Iterator::Rule#SEE-ALSO . For more
about that, see:

http://shlomif-tech.livejournal.com/29315.html

Regards,

Shlomi Fish

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Re: project euler #8

[Shlomi Fish]

Hi lee,

I decided to try to give you another chance to be educated, despite Uri's
conclusion in the other thread. Hopefully you won't let me down.

On Thu, 25 May 2017 16:48:13 +0100
lee <l...@yagibdah.de> wrote:

> Shlomi Fish <shlo...@shlomifish.org> writes:
> 
> > [...]  
> >> >> while ( my $numbline =  ) {
> >> >> chomp $numbline;
> >> >> my @numbline = split //, $numbline;
> >> >
> >> > You're processing the input number line-by-line, but it's one whole
> >> > number and the products may span across more than one line. You need to
> >> > slurp it and prepare an array of digits.
> >> 
> >> Isn't it more efficient to put all the digits into a string rather than
> >> into an array and use substr()?
> >>   
> >
> > I believe it should be more space efficient, but perl shouldn't have a
> > problem managing an array of a 1,000 digits on most machines.  
> 
> Yes, I'm just wondering.
> 
> It doesn't even depend on how many digits there are because it's
> possible to consider only the relevant portion of the digits in each
> step.
> 

Thinking about it one may wish to use the
https://en.wikipedia.org/wiki/Stream_(computing) pattern (if one calls it
that) and just keep a https://en.wikipedia.org/wiki/Circular_buffer of the last
13 or so elements.

> > See https://duckduckgo.com/?q=premature+optimization+evil+quote=web
> > - we should worry about optimising when we need to - not before.  
> 
> I don't agree that all optimization is evil to begin with.  I can not
> write a line of code without optimizing first because otherwise, I
> wouldn't know what to write.  Can you?
> 
> Knowing what is more efficient helps me before the first line of a
> program is written and with every single line of it.  I couldn't do any
> overall design without knowing.
> 
> Even syntax highlighting, reasonable formatting and reasonable use of
> comments is an optimization.
> 
> The point is to do the right amount of optimization which allows you to
> make appropriate progress towards a working version.  Once you have that,
> you can optimize more or leave it as is.
> 
> Programming is a creative process of optimization.
> 

First of all note that I strongly believe the quote referred to speed / runtime
optimisation - not to https://en.wikipedia.org/wiki/Code_refactoring ,
cleanups , bug fixes , code design and other unrelated activities. Secondly, it
talked about *premature* optimisation, where you spend a lot of time optimising
before there is a proven and genuine need for it. There is such a thing as
"Time to market" and also needlessly changing the code always risks introducing
bugs, so one should try to avoid it.

> 
> Since we're looking at a mathematical excersise here, we might use it to
> learn something about programming :)
> 
> > Using arrays allows us to use convenient operators and functions that
> > are less native to strings.  
> 
> Ok, let me be a smartass:
> 
> substr() is only so native to strings as perl does not do implicit
> typecasting.

What is "typecasting" in this context?

> 
> The operator in question is multiplication.  Are there different
> multiplication operators in perl which are more or less convenient?
> 

There is https://metacpan.org/pod/List::Util#product and I also refer to array
slicing (e.g @array[@indices]), map, grep, and lots of other stuff.

> Did I use inconvenient operators?
> 
> > Also note that using http://perldoc.perl.org/functions/vec.html should
> > allow to store a digit within 4 bits in a binary buffer, which is even
> > better than using a string.  
> 
> Hm, I don't understand this documentation.  This function seems to be
> designed to mess up things by confusing strings with bytes and could be
> considered as a symptom of perl not having variables of fixed types.
> 

vec uses a binary buffer as input, which is usable as a non-unicode string.

> Maybe I'd understand from a safe and evident use case for it.
>

Let's say you want to have a https://en.wikipedia.org/wiki/Bit_array that maps
non-negative integers to a false/true value. You can initialise it as
all-Falses using «my $bit_vec = '';» and then set or lookup «vec($bit_vec,
$idx, 1)». This is useful for
https://en.wikipedia.org/wiki/Generating_primes#Prime_sieves - prime sieving.

> > Some comments about your code:
> >  
> 
> > [...]  
> >> 
> >> my $data = "
> >> 73167176531330624919225119674426574742355349194934
> >> 96983520312774506326239578318016984801869478851843  
> > [...]  
> >> ";
> >>   
> >
> > Please use here-documents for mul

Re: project euler #8

[Shlomi Fish]

Hi lee!

On Thu, 25 May 2017 02:24:05 +0100
lee <l...@yagibdah.de> wrote:

> Shlomi Fish <shlo...@shlomifish.org> writes:
> 
> > Hi all!
> >
> > Resending because the original message does not appear to have arrived at
> > the list.
> >
> > =
> >
> > Hi Derrick,
> >
> > On Tue, 16 May 2017 14:01:34 +0800
> > derr...@thecopes.me wrote:
> >  
> >> Hi All,
> >> 
> >> I am working on problem #8 of the euler project. see below.
> >> 
> >> 
> >> I have the below solution below for this which works fine but gives me the
> >> wrong answer. I checked shlomifish's solution on github and his is similar
> >> to mine, more elegant since he uses "map", but he gets a different answer.
> >> I feel like I have some basic misunderstanding about how something should
> >> work. Or maybe I am misunderstanding the problem. Thanks in advance for
> >> any push in the right direction. see my solution below.
> >> 
> >> Derrick
> >> 
> >> #! /usr/bin/env perl
> >> 
> >> use strict;
> >> use warnings;
> >> use 5.024;
> >> use List::Util qw(max product);
> >> 
> >> my $totalmax = 0;
> >> 
> >> while ( my $numbline =  ) {
> >> chomp $numbline;
> >> my @numbline = split //, $numbline;  
> >
> > You're processing the input number line-by-line, but it's one whole number
> > and the products may span across more than one line. You need to slurp it
> > and prepare an array of digits.  
> 
> Isn't it more efficient to put all the digits into a string rather than
> into an array and use substr()?
> 

I believe it should be more space efficient, but perl shouldn't have a problem
managing an array of a 1,000 digits on most machines. See
https://duckduckgo.com/?q=premature+optimization+evil+quote=web - we should
worry about optimising when we need to - not before. Using arrays allows us to
use convenient operators and functions that are less native to strings.

Also note that using http://perldoc.perl.org/functions/vec.html should allow to
store a digit within 4 bits in a binary buffer, which is even better than using
a string.

Some comments about your code:

> 
> With a bit extra ado you could omit, for the sake of verifyability (It
> doesn't matter in which order you do the multiplications of the adjacent
> digits as long as they are adjacent.):
> 
> 
> #!/usr/bin/perl
> 
> use strict;
> use warnings;
> 
> 
> my $data = "
> 73167176531330624919225119674426574742355349194934
> 96983520312774506326239578318016984801869478851843
> 85861560789112949495459501737958331952853208805511
> 12540698747158523863050715693290963295227443043557
> 66896648950445244523161731856403098711121722383113
> 6222989342338030813533627661428280686645238749
> 30358907296290491560440772390713810515859307960866
> 70172427121883998797908792274921901699720888093776
> 65727333001053367881220235421809751254540594752243
> 52584907711670556013604839586446706324415722155397
> 53697817977846174064955149290862569321978468622482
> 83972241375657056057490261407972968652414535100474
> 82166370484403199890008895243450658541227588666881
> 16427171479924442928230863465674813919123162824586
> 17866458359124566529476545682848912883142607690042
> 2421902267105562632109370544217506941658960408
> 07198403850962455444362981230987879927244284909188
> 84580156166097919133875499200524063689912560717606
> 05886116467109405077541002256983155200055935729725
> 71636269561882670428252483600823257530420752963450
> ";
> 

Please use here-documents for multi-line strings - see
http://perl-begin.org/tutorials/bad-elements/#string-notation .

> $data =~ s/\n//g;
> 

Nice! Perhaps use \s or [^0-9] instead though.
> my $adjacency = 13;
> my $maxprod = 0;
> 
> my $start = 0;
> my $end = length($data) - $adjacency;
> 
> while($start < $end) {

This should be a «for my $idx ($start .. $end-1)» loop.
>   my $adjunct = 1;
>   my $prod = substr($data, $start, 1);
>   print "$prod";
>   while($adjunct < $adjacency) {

Again.

> my $ad = substr($data, $start + $adjunct, 1);
> print " * $ad";
> $prod *= $ad;
> $adjunct++;
>   }
>   print " = $prod\n";
>   $maxprod = $prod if($maxprod < $prod);
> 
>   $start++;
> }
> 
> print "The largest product of $adjacency adjacent numbers is $maxprod.\n";
> 
> exit 0;
> 

No need for the exit statement here.

> 
> Is this supposed to be a programming exercise?  It's a purely
> mathematical one to me.
> 

See https://en.wikipedia.org/wiki/Project_Euler for the Project Euler mission
and motivation.

Regards,

Shlomi Fish

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Re: Perl/Tk

[Shlomi Fish]

On Tue, 16 May 2017 20:35:55 +0900
Masayoshi Fujimoto  wrote:

> Hi.
> I really appriciate your help. It worked for me.
> 

You're welcome!

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Re: Perl/Tk

[Shlomi Fish]

Hi!

On Tue, 16 May 2017 20:11:52 +0900
Masayoshi Fujimoto  wrote:

> Hi.
> 
> I would like to get $celebrity.
> 
> How should I do?
>

I have modified your code based on
https://metacpan.org/pod/distribution/Tk/pod/Entry.pod to get what seems to be
the desired result:

« «
#!/usr/local/bin/perl

use strict;

use warnings;

use autodie;

use v5.10;

use Tk;

my $top = MainWindow->new();

my $f1 = $top->Frame()->pack();

my $f2 = $top->Frame()->pack();

$f1->Label(-text => "Celebrity:")->pack(-side => "left");

my $celebrity = $f1->Entry();

$celebrity->pack(-side => "left");

my $name = "Ayumi Kinoshita";

$f2->Button(-text => "OK",-command => [ \,
$celebrity,$name])->pack(-side => "left");

$f2->Button(-text => "Cancel",-command => sub {exit;})->pack();

MainLoop();

sub onButton {

my ($celebrity,$name) = @_;

say $celebrity;

say $name;

say "Celebrity string = <", $celebrity->get(), ">";

}

»

One note is http://perl-begin.org/tutorials/bad-elements/#prototypes ,
otherwise your code seems pretty solid.

Regards,

Shlomi

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Re: project euler #8

[Shlomi Fish]

On Tue, 16 May 2017 17:53:17 +0800
"derrick" <derr...@thecopes.me> wrote:

> OK thanks, I understand now. I was reading 20 50-digit numbers rather than 1
> 1000-digit numbers. I knew it a fundamental misunderstanding somewhere. Thank
> you again,
>

You're welcome!

-- Shlomi
 
> Derrick
> 
> ------
> 发件人：Shlomi Fish<shlo...@shlomifish.org>日　期：2017年05月16日
> 16:54:39收件人：<derr...@thecopes.me>抄　送：Beginners Perl
> List<beginners@perl.org>主　题：Re: project euler #8Hi all!
> 
> Resending because the original message does not appear to have arrived at the
> list.
> 
> =
> 
> Hi Derrick,
> 
> On Tue, 16 May 2017 14:01:34 +0800
> derr...@thecopes.me wrote:
> 
> > Hi All,
> > 
> > I am working on problem #8 of the euler project. see below.
> > 
> > 
> > I have the below solution below for this which works fine but gives me the
> > wrong answer. I checked shlomifish's solution on github and his is similar
> > to mine, more elegant since he uses "map", but he gets a different answer. I
> > feel like I have some basic misunderstanding about how something should
> > work. Or maybe I am misunderstanding the problem. Thanks in advance for any
> > push in the right direction. see my solution below.
> > 
> > Derrick
> > 
> > #! /usr/bin/env perl
> > 
> > use strict;
> > use warnings;
> > use 5.024;
> > use List::Util qw(max product);
> > 
> > my $totalmax = 0;
> > 
> > while ( my $numbline =  ) {
> > chomp $numbline;
> > my @numbline = split //, $numbline;  
> 
> You're processing the input number line-by-line, but it's one whole number and
> the products may span across more than one line. You need to slurp it and
> prepare an array of digits.
> 
> > say "@numbline ";
> >my @product = (); 
> > for (0..$#numbline - 13) {  
> 
> This should be "@numbline - 13" - an off-by-one error.
> 
> Regards,
> 
>   Shlomi Fish

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Re: project euler #8

[Shlomi Fish]

Hi all!

Resending because the original message does not appear to have arrived at the
list.

=

Hi Derrick,

On Tue, 16 May 2017 14:01:34 +0800
derr...@thecopes.me wrote:

> Hi All,
> 
> I am working on problem #8 of the euler project. see below.
> 
> 
> I have the below solution below for this which works fine but gives me the
> wrong answer. I checked shlomifish's solution on github and his is similar to
> mine, more elegant since he uses "map", but he gets a different answer. I
> feel like I have some basic misunderstanding about how something should work.
> Or maybe I am misunderstanding the problem. Thanks in advance for any push in
> the right direction. see my solution below.
> 
> Derrick
> 
> #! /usr/bin/env perl
> 
> use strict;
> use warnings;
> use 5.024;
> use List::Util qw(max product);
> 
> my $totalmax = 0;
> 
> while ( my $numbline =  ) {
> chomp $numbline;
> my @numbline = split //, $numbline;

You're processing the input number line-by-line, but it's one whole number and
the products may span across more than one line. You need to slurp it and
prepare an array of digits.

> say "@numbline ";
>my @product = (); 
> for (0..$#numbline - 13) {

This should be "@numbline - 13" - an off-by-one error.

Regards,

Shlomi Fish

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Re: keyboard input without pressing return?

[Shlomi Fish]

On Sun, 14 May 2017 12:08:59 +0300
Shlomi Fish <shlo...@shlomifish.org> wrote:

> Hi lee,
> 
> On Sat, 06 May 2017 02:06:19 +0100
> lee <l...@yagibdah.de> wrote:
> 
> > Hi,
> > 
> > how can a sleeping program react to a key that was pressed without
> > return being pressed?
> > 
> > 
> > perl -e 'use Term::ReadKey; my $ke = ReadKey(10); print "k: $ke\n";'
> > 
> > 
> > ... shows that:
> > 
> > 
> > + ReadKey() returns undef after the timeout
> > 
> > + ReadKey() returns undef after the timeout even when you pressed keys
> > 
> > + ReadKEy() returns the first key of those that were pressed before the
> > timeout expires when you hit return before it does
> > 
> > 
> > So you always have to hit return :(
> > 
> > I'm finding that entirely useless for instances in which a program is
> > sleeping for some time (let's say 10 minutes) but supposed to do
> > something immediately when a key is pressed, and without pressing
> > return.  For example, I might want to press 'q' to quit and don't want
> > to wait 10 minutes for the program to react, and of course, I don't want
> > to press enter.
> > 
> > How can that be done?
> > 
> >   
> 
> This program from perldoc Term::ReadKey is working as advertised:
> 
> «
> #!/usr/bin/perl
> 
> use strict;
> use warnings;
> 
> use Term::ReadKey;
> ReadMode 4; # Turn off controls keys
> my $key;
> while (not defined ($key = ReadKey(-1))) {
> # No key yet
> }
> print "Get key $key\n";
> ReadMode 0; # Reset tty mode before exiting
> 
> »
> 
> Note that it may be a busy loop. It mad be a bug in Term::ReadKey or you're
> doing something wrong.
> 

I've now tried this program and it seems to do what you want:

perl -e 'use Term::ReadKey; ReadMode 4; my $ke = ReadKey(3); print "k: $ke\n";
ReadMode 0;'

The key (pardon the pun) is adding the ReadMode calls.

Regards,

Shlomi Fish

> Regards,
> 
>   Shlomi Fish
> 



-- 
-
Shlomi Fish   http://www.shlomifish.org/
Perl Humour - http://perl-begin.org/humour/

XSLT is the number one cause of programmers’ suicides since Visual Basic 1.0.
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Re: keyboard input without pressing return?

[Shlomi Fish]

Hi lee,

On Sat, 06 May 2017 02:06:19 +0100
lee <l...@yagibdah.de> wrote:

> Hi,
> 
> how can a sleeping program react to a key that was pressed without
> return being pressed?
> 
> 
> perl -e 'use Term::ReadKey; my $ke = ReadKey(10); print "k: $ke\n";'
> 
> 
> ... shows that:
> 
> 
> + ReadKey() returns undef after the timeout
> 
> + ReadKey() returns undef after the timeout even when you pressed keys
> 
> + ReadKEy() returns the first key of those that were pressed before the
> timeout expires when you hit return before it does
> 
> 
> So you always have to hit return :(
> 
> I'm finding that entirely useless for instances in which a program is
> sleeping for some time (let's say 10 minutes) but supposed to do
> something immediately when a key is pressed, and without pressing
> return.  For example, I might want to press 'q' to quit and don't want
> to wait 10 minutes for the program to react, and of course, I don't want
> to press enter.
> 
> How can that be done?
> 
> 

This program from perldoc Term::ReadKey is working as advertised:

«
#!/usr/bin/perl

use strict;
use warnings;

use Term::ReadKey;
ReadMode 4; # Turn off controls keys
my $key;
while (not defined ($key = ReadKey(-1))) {
# No key yet
}
print "Get key $key\n";
ReadMode 0; # Reset tty mode before exiting

»

Note that it may be a busy loop. It mad be a bug in Term::ReadKey or you're
doing something wrong.

Regards,

Shlomi Fish

-- 
-
Shlomi Fish   http://www.shlomifish.org/
http://www.shlomifish.org/humour/bits/New-versions-of-the-GPL/

As it turns out, compiling a C program from more than 20 years ago is actually
a lot easier than getting a Rails app from last year to work.
— https://passy.svbtle.com/building-vim-from-1993-today

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Re: prime factors

[Shlomi Fish]

Hi Derrick,

On Wed, 03 May 2017 06:58:44 +0800
"derrick" <derr...@thecopes.me> wrote:

> Thank you for your complete answer. How much memory is used per array element?
>

In Perl, it can be quite a bit because an array contains a vector of pointer to
"SV"s, and each SV may contain an integer, a string, a reference, a floating
point number, etc. There's also the issue of memory fragmentation.

You can mitigate some of that by using
http://perldoc.perl.org/functions/vec.html or something like
https://en.wikipedia.org/wiki/Perl_Data_Language . 
> I will work on a shorter algorithm. This one worked on shorter numbers so I
> just used it for this.
> 

By shorter do you mean 'faster in runtime speed'? There's also
https://en.wikipedia.org/wiki/Code_golf .



> Derrick
> 
> 
> --发件人：Jim
> Gibson<jimsgib...@gmail.com>日　期：2017年05月03日 00:35:53收件人：derrick
> cope<derr...@thecopes.me>; beginners<beginners@perl.org>主　题：Re: prime
> factors
> > On May 2, 2017, at 7:58 AM, derrick cope <derr...@thecopes.me> wrote:
> > 
> > I was writing a program to solve the #3 exercise on project Euler. I needed
> > to find the prime factors of a given number. I have solved it already but a
> > couple of the ways I tried to solve the problem caused a problem.  
> 
> Exercise #3 is to find the largest prime factor of the number 600,851,475,143.
> 
> > 
> > The below worked for smaller numbers but when I used the 12 digit number
> > given by project Euler I got "Out of memory!"
> > 
> > chomp( my $factor = <>);
> > my @primefactor = grep { ( $_ ) } ( grep { $factor % $_ == 0 }
> > 1..$factor );  
> 
> Presumably, you have entered the number 600851475143 into the command line
> that executes your program. Therefore, $factor is equal to 600851475143  and
> the expression 1..$factor will be a list of 600851475143 elements; ( 1, 2, 3,
> … , 600851475143 ). You will need a computer with several petabytes of memory
> to store that list.
> 
> > 
> > sub isprime { 
> > my $numb = shift;
> > my @quot = grep { 
> >if ( $numb % $_ == 0 ) {1;
> >} else { 0;} 
> > } 2..$numb-1;
> > unless ( @quot ) {
> >1;
> >#say "prime";
> >} else {
> >0;
> >#say "not prime";
> >}
> > }  
> 
> This function also generates a very long list of integers (2..$numb-1).
> 
> > 
> > 
> > This one worked but caused my computer to crash.
> > 
> > my $xxx = 1;
> > while ( $xxx < $factor ) {
> >if ( $factor % $xxx == 0 and ($xxx) ) {
> >say $xxx;
> >}
> >$xxx++
> > }
> > 
> > what is causing perl to do this?  Would using a module save memory?
> > Thanks for any help.  
> 
> Using a module would not save significant memory. You need to devise an
> algorithm that does not require long lists of numbers. You need to test each
> potential prime factor one at a time. You will also need to address the fact
> that Perl’s integers cannot represent the number 600851475143 in their normal
> 32- or 64-bit formats. See ‘perldoc bignum’.
> 
> Also note that the smallest factor of any number cannot be larger than the
> square root of that number, so the function isprime need not consider
> potential factors larger than the square root of its argument.
> 
> 
> 
> 
> Jim Gibson
> 
> 



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-
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Re: prime factors

[Shlomi Fish]

Hi derrick!

Welcome aboard!

See below for my reply.

On Tue, 02 May 2017 22:58:58 +0800
"derrick cope" <derr...@thecopes.me> wrote:

> I was writing a program to solve the #3 exercise on project Euler. 

For reference, it is https://projecteuler.net/problem=3 .

>I needed
> to find the prime factors of a given number. I have solved it already but a
> couple of the ways I tried to solve the problem caused a problem.
> 
> The below worked for smaller numbers but when I used the 12 digit number
> given by project Euler I got "Out of memory!"
> 
> chomp( my $factor = <>);
> my @primefactor = grep { ( $_ ) } ( grep { $factor % $_ == 0 }
> 1..$factor ); 

First of all, please go over http://perl-begin.org/tutorials/bad-elements/ and
avoid these bad elements. add 'use strict;' and 'use warnings;' and avoid
calling subroutines with ampersands.

In that line's case you're building several very long lists. In this case a
foreach loop will be better. Also not that you can also write the nested greps
as grep { $factor % $_ == 0 and isprime($_)} ... .

>sub isprime { 
> my $numb = shift;
> my @quot = grep { 
>     if ( $numb % $_ == 0 ) {1;
>     } else { 0;} 
> } 2..$numb-1;
> unless ( @quot ) {
>     1;
>     #    say "prime";
>     } else {
>     0;
>     #    say "not prime";
>     }
> }
>

your indentation is lacking, and better see
http://perl-begin.org/tutorials/bad-elements/#grep_instead_of_any . Also use
an explicit return and don't use if or unless to return a value. (you can try
using the ? : ternary conditional operator instead).

> 
> This one worked but caused my computer to crash.
> my $xxx = 1;
> while ( $xxx < $factor ) {
>     if ( $factor % $xxx == 0 and ($xxx) ) {
>     say $xxx;
>     }
>     $xxx++
> }
> what is causing perl to do this?  Would using a module save memory?Thanks for
> any help.

That looks better memory wise. But "isprime()" is still sub-optimal.

Note that you can optimise the algorithm considerably by using some tricks. See:

https://duckduckgo.com/?q=project+euler+3=web

Perhaps see https://duckduckgo.com/?q=prime+factorization=web too.

Regards,

Shlomi Fish

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Re: Perl reserved words

[Shlomi Fish]

Hi Frank,

On Sun, 23 Apr 2017 10:07:56 -0700
SSC_perl <p...@surfshopcart.com> wrote:

>   Is ‘vendor’ a reserved word of some type in either Perl, MySQL, or
> DBM?  

It is not a reserved word of Perl. No idea about MySQL.

> I tried to add a ‘vendor’ field to SurfShop but it didn’t work.  I
> don’t recall exactly what happened now (sorry), but I had to settle on
> another word to get it to work.
> 
>   Any ideas on what it could have been?
> 
> Thanks,
> Frank
> 
> It’s not listed here:
> http://learn.perl.org/docs/keywords.html
> 



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Re: How to delete multiple indices from array

[Shlomi Fish]

Hi Uri!

Some notes.

On Wed, 12 Apr 2017 15:19:33 -0400
Uri Guttman <u...@stemsystems.com> wrote:

> On 04/12/2017 03:00 PM, David Emanuel da Costa Santiago wrote:
> > Hello!
> >
> > What's the best way to delete multiple indices from an array?
> >
> > i'm doing:
> >
> > ---
> > my @array=qw/zero one two three four five six seven eight nine ten/;
> >
> > my @indicesToDelete = (2,4,6,7);  
> 
> if you have the indexes to keep, this would be a simple slice:
> 
> my @keep_indexes = ( 0, 1, 3, 5, 8,9 10 );
> @array = @array{ @keep_indexes } ;
> 

it should be «@array = @array[ @keep_indexes ] ;» instead. With curly braces
it's a hash slice.

> so one idea is to make that list of kept indexes from the list of 
> indexes to delete:
> 
> my %keep_hash ;
> @keep_hash{ 0 .. 10 } = () ; # no need for any values so this save space
> delete @keep_hash{ @keep_indexes } ;
> @array = @array{ keys %keep_hash } ;

1. again - square brackets instead of curly braces.

2. You should sort the keys numerically using sort { $a <=> $b }.

3. Better use « keys@array» or in older perls «0 .. $#array» to avoid hard
coding the values and magic constants.



some other ways I can think of doing it:

1.

my %blacklist;
@blacklist{@remove} = ();
@array = @array[grep {!exists $blacklist{$_} } keys@array];

2. 

my @new;
while (my ($i, $v) = each@array)
{
if (@remove and $i == $remove[0])
{
shift@remove;
}
else
{
push @new, $v;  
}
}
@array = @new

===

https://en.wikipedia.org/wiki/There%27s_more_than_one_way_to_do_it

Regards,

Shlomi Fish

> >
> > my %hash;
> >
> > @hash{(0..scalar(@array)-1)} = @array;
> >
> > delete $hash{$_} for @indicesToDelete;  
> delete can be used on a slice
> 
> delete @hash{ @indicesToDelete } ;
> 
> uri
> 
> Perl Guru for hire. Available for contract/full time/part time Perl hacking.
> 

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Re: WWW::Mechanize requires wget

[Shlomi Fish]

On Tue, 4 Apr 2017 10:43:27 -0700
SSC_perl <p...@surfshopcart.com> wrote:

>   This is a heads up for anyone wanting to use WWW::Mechanize on OS X.  
> 
>   I’ve been fighting with WWW::Mechanize all morning, trying to get it
> to work with no success.  There were no error messages telling me what was
> wrong.  I checked my firewall to see if anything was being blocked, but it
> wasn’t.  I finally ran across a post where someone was asked if they were
> able to access the target web site using wget, so I decided to try that
> myself.  Terminal told me that wget wasn’t found.  So… off to homebrew to
> install wget, and lo and behold, Mech now works!  I went back to see if Mech
> had wget as a dependency, but nothing was mentioned on CPAN.
> 
>   So just in case someone else was having the same trouble, I thought
> I’d post this.  Not sure why wget wasn’t installed with Xcode Developer Tools.
> 
> Frank

Hi Frank!

What you say sounds strange. WWW-Mech should not require wget. Perhaps they
both use a common dependency.

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Fw: how to recursion

[Shlomi Fish]

Forwarding to the list.

Begin forwarded message:

Date: Wed, 29 Mar 2017 11:32:08 -0400
From: Shawn H Corey <shawnhco...@gmail.com>
To: Shlomi Fish <shlo...@shlomifish.org>
Subject: Re: how to recursion


On Wed, 29 Mar 2017 17:22:36 +0300
Shlomi Fish <shlo...@shlomifish.org> wrote:

> my_recursion accepts $self as its first argument, so you should pass
> it there. Doing «my_recursion($self);» is one option for doing that
> but : 1. It looks ugly. 2. It's less future proof. 3. It's a bad
> practice for OOP perl.
> 
> The original code was fine.  

Oops, you're right. the OOLs I've been using lately take care self (or
this) automatically. I had forgotten that Perl is an OO toolkit, not an
OOL. ☺


-- 
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Shawn H Corey

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Re: how to recursion

[Shlomi Fish]

Hi Shawn!

On Wed, 29 Mar 2017 08:09:12 -0400
Shawn H Corey  wrote:

> On Wed, 29 Mar 2017 09:25:06 +0800
> PYH  wrote:
> 
> > sub my_recursion {
> >  my $self = shift;
> >  
> >  if (...) {
> >  $self->my_recursion;  
> 
> # you don't need $self. subroutine lookup starts
> # in the same package. Just the sub by itself
> # is good enough.
> my_recursion();
> 

my_recursion accepts $self as its first argument, so you should pass it there.
Doing «my_recursion($self);» is one option for doing that but : 1. It looks
ugly. 2. It's less future proof. 3. It's a bad practice for OOP perl.

The original code was fine.

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Re: [OT] app (ncurses?) mechanizer?

[Shlomi Fish]

Hi Paul!

On Mon, 27 Mar 2017 22:21:06 +0200
Paul Johnson <p...@pjcj.net> wrote:

> On Mon, Mar 27, 2017 at 04:04:22PM +0200, Luca Ferrari wrote:
> > Hi all,
> > I've to run a very old application from the command line (unix), it
> > seems to me a ncurses application but I'm not sure that is the real
> > case (let's say it seems ncurses).
> > Anyway, I have to launch the application with a file name, do a couple
> > of menu interactions and exit, then do it again for a hundred or so
> > files.
> > Is there any kind of "app-mechanize" similar to www::mechanize?  
> 
> Nothing to do with perl, but you could try xdotool
> 
>   http://www.semicomplete.com/projects/xdotool/
> 

The original poster was asking about automating an ncurses/etc. unix *terminal*
app - not an X11-based app which is what xdotool is for. Note that for X11,
there's https://metacpan.org/release/X11-GUITest on CPAN and other similar
toolkits in other languages as well.


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Re: [OT] app (ncurses?) mechanizer?

[Shlomi Fish]

Hi Luca,

On Mon, 27 Mar 2017 16:04:22 +0200
Luca Ferrari  wrote:

> Hi all,
> I've to run a very old application from the command line (unix), it
> seems to me a ncurses application but I'm not sure that is the real
> case (let's say it seems ncurses).
> Anyway, I have to launch the application with a file name, do a couple
> of menu interactions and exit, then do it again for a hundred or so
> files.
> Is there any kind of "app-mechanize" similar to www::mechanize?
> 

See https://metacpan.org/release/Expect . 

> Thanks,
> Luca
> 



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Re: Using PerlPod creatively

[Shlomi Fish]

Hi, Sami!

Please reply to all recipients.

On Fri, 24 Mar 2017 00:17:33 -0700
Sami Joseph <sami.jos...@gmail.com> wrote:

> Hi,
> 
> I am interested to understand what this guy did, but i am unable to, can
> someone please break it down to a newbie
> 
> I've spent the last several days at work, trying to "take over" some work
> left behind by a departing colleague. I realized we didn't have some of his
> bash scripting in ansible or in a repo, so I decided this would be a good
> opportunity to fix all of those problems. After a little while it became
> clear his script was a set of functions, run in a loop-within-a-loop to
> iterate through a bunch of things. In the middle, between these two loops,
> is a pile of inline *PERL* that runs as a bash function and passes data

See http://perl-begin.org/learn/Perl-perl-but-not-PERL/ - it should not be
capitalised as "PERL".

> back and forth in all directions. This Perl generates some dynamic SQL
> commands each loop.
> 
> I hate SQL.
> 
> Okay... read the Perl. Now, it's been a long time and a long way since my
> last string of PERLs, so i didn't really grok 100% what I was reading, but
> I got the gist of it. Finally figured out the SQL wasn't the problem.
> 
> Another day goes by, and I finally figure out his code is self documenting!
> That was what all the little bits were in the perl I didnt get. PerlPod. So
> now I can figure this out easy . Run it, read the code, make a change, run
> it... *boom* what?
> 
> Nope.
> 
> It took me several more hours and a few beer, and it finally clicked. He
> was using PerlPod to document out the code he didn't want to run, and
> commented out the documenting code to run the code he wanted. What looked
> commented out, wasn't, and what looked like a pile of variables being set,
> was just a bunch of commentary. He was using a documentation module for
> *flow control*.

today I learned that it can be spelled as "Perl Pod" -
http://perldoc.perl.org/perlpod.html - I thought "POD" was the correct
spelling. Anyway, you are right that it can be used for excluding code from
being compiled. The common idiom is:

=begin removed

.
.
.

=end removed

=cut

Anyway, using Pod for Perl code embedded in bash or other shells is really
"What-the-f??"-y. One should avoid embedding such long code (beyond a short
-e or -E string) in bash at all, and keep the code in a separate program file
(also see the Modulino concept -
http://perltricks.com/article/107/2014/8/7/Rescue-legacy-code-with-modulinos/
and https://www.masteringperl.org/category/chapters/modulinos/ ).

Regards,

Shlomi Fish  
> 
> What a Hacker. Holy shit. Blew. My. Mind.
> 
> I just got schooled very seriously. It's nice to know I can still improve
> *that much*, even from where I am.
> 
> 
> When PerlPod is used to document something, anything between control codes
> is not interpreted but treated as commented text. He would comment out the
> control codes (thus rendering the text interpretable) on the parts meant to
> run, which would differ between machines.



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Re: accessors module

[Shlomi Fish]

Hi pyh,

On Thu, 16 Mar 2017 09:49:34 +0100 (CET)
p...@vodafonemail.de wrote:

> Hello members,
> 
> I was not sure, what purpose does module accessors exist for?
> 

Do you mean https://metacpan.org/release/accessors ? If so, there are many
other accessor generators on CPAN and object systems such as Moose or Moo
provide many more features. For a little about the motivation behind setters,
getters and accessors, see this page on a site I maintain (note the anchor):

http://perl-begin.org/tutorials/perl-for-newbies/part5/#page--accessors--DIR

Regards,

    Shlomi Fish
 
> something similar to ruby's meta-programming?
> 
> Thanks.



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Re: Installing Net::SFTP

[Shlomi Fish]

Hi Uday,

On Wed, 15 Mar 2017 11:52:53 +0530
Uday Vernekar <vernekaru...@gmail.com> wrote:

> Hello,
> 
> Need some help on installing Net::SFTP perl module on RHEL.
> 
> please guide.
> 

What did you try ? What happened? You may be able to find an .rpm package of
"perl-Net-SFTP" on various package repositories. Otherwise you can try doing
"cpan -i Net::SFTP" (possibly after installing some compilers and libararies'
*-devel pacakges). Good luck!

Regards,

-- Shlomi


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Re: how to read a picture

[Shlomi Fish]

Hi community tech,

On Sun, 12 Mar 2017 13:34:21 +0800
community tech <commun...@dnsbed.com> wrote:

> Hi,
> 
> Giving a pic which is 5x5 pixels, I want to read the grayscale value of
> each pixel.
> which module should I use? thanks.

There's https://metacpan.org/release/GD and there are also the Perl bindings to
https://en.wikipedia.org/wiki/ImageMagick and
https://en.wikipedia.org/wiki/GraphicsMagick . Also of interest may be
https://en.wikipedia.org/wiki/GIMP and GUI frameworks such as the ones in
http://www.shlomifish.org/open-source/portability-libs/ (note that it's a page
on my site).

Good luck!

Regards,

Shlomi Fish

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Re: multiple named captures with a single regexp

[Shlomi Fish]

Hi Luca,

On Wed, 1 Mar 2017 10:01:34 +0100
Luca Ferrari <fluca1...@infinito.it> wrote:

> Hi all,
> I'm not sure if this is possible, but imagine I've got a line as follows:
> 
> command arg1 arg2 arg3 arg4 ...
> 
> I would like to capture all args with a single regexp, possibly with a
> named capture, but I don't know exactly how to do:
> 
> my $re = qr/command\s+(?\w+)+/;
> 
> the above of course is going to capture only the first one (one shoot)
> or the last one within a loop.
> How can I extract the whole array of arguments?
> 

Perhaps try using \G and the /g and possibly /o flags , see:

http://perl-begin.org/uses/text-parsing/

(Note that perl-begin is a site that I maintain).

Regards,

Shlomi Fish


> Please note, a raw solution is to remove the command and split, but
> I'm asking for a more elegant solution.
> 
> Thanks,
> Luca
> 



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Re: Parsing Logfiles and fetching Macs programmed and putting in another file.

[Shlomi Fish]

On Tue, 31 Jan 2017 17:29:10 +0530
Uday Vernekar <vernekaru...@gmail.com> wrote:

> Thanks shlomi ,working on your inputs...Thanks:)
> 

You're welcome, Uday!

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Re: Parsing Logfiles and fetching Macs programmed and putting in another file.

[Shlomi Fish]

; }
> }
> 
> close(SCRIPT);
> chdir($startdir) or die "Unable to change to dir $startdir:$!\n";
> }
> 
> my $date =`date`;

use localtime() - http://perldoc.perl.org/functions/localtime.html

> my $data_file2='/mnt/ONT/MAC-REPORT-FILE.txt';
> open DATAOUT, ">>$data_file2" or die "can't open $data_file2 $!";
> print DATAOUT "\n\t\t\tMAC-ID GENERATED REPORT\n";
> print DATAOUT "\nGeneteated By:$user\n";

you misspelled "Generated".

> print DATAOUT "\nDATE: $date \n";
> print DATAOUT "NOTE: THIS REPORT IS GENERATED BASED ON THE TEST LOGS
> AVAILABLE IN THE SERVER\n";
> print DATAOUT "\n";
> print DATAOUT " SERIAL NUMBER\t\tMACADDRESS\n";
> print DATAOUT "-\n";
> close(DATA);
> 
> sub CheckFile{
> my($name) = shift;
> 
> my $datafile=$name;
> #print "$datafile\n";
> my $data_file2='/mnt/ONT/MAC-REPORT-FILE.txt';
> 
> open DATA, "$datafile" or die" can't open $datafile $!";
> my @array_of_data=;
> 
> #print @array_of_data;
> 
> foreach my $i ($datafile)
> {

You're iterating over a scalar instead of a list.

> 
> my $Result = `grep "Base MAC Address" \/mnt\/backup\/$Directory\/$name |
> tail -n 1 `;

don't use /bin/grep when you can use perl's file and text processing tools.

> my ($str,@mac) = split(":",$Result);
> if($mac[1] ne "05")  {
> 
> @mac="   MAC NOT PROGRAMMED\n";
> #print "\n";
> print DATAOUT " $name\t\t@mac\n" ;
> }
> else{
> print DATAOUT " $name\t\t
> $mac[0]:$mac[1]:$mac[2]:$mac[3]:$mac[4]:$mac[5]\n" ;
> }
> }
> }
> 
> ($userPath);
> 
> close(DATAOUT);
> 
> 
> 
> 
> 

In short - this code should really be refactored, corrected, and modernised.
Perhaps you should read http://www.onyxneon.com/books/modern_perl/index.html or
a similar book or tutorial - see http://perl-tutorial.org/ and
http://perl-begin.org/ .

Regards,

Shlomi Fish

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Re: application starter kit

[Shlomi Fish]

On Mon, 23 Jan 2017 10:44:18 +0100
Luca Ferrari <fluca1...@infinito.it> wrote:

> On Mon, Jan 23, 2017 at 10:39 AM, Chas. Owens <chas.ow...@gmail.com> wrote:
> > I think you are saying you want to be able to create one file you can give
> > to someone else and have them run a Perl 5 program you have written without
> > having to install all of the modules (and possibly even perl itself).  If
> > this is the case, then you are in luck.  There are a couple of solutions
> > that exist today:  
> 
> No, sorry, I misexplained my aim: I want to be able to do all normal
> CPAN stuff like installing my module, testing, getting dependencies,
> but with the final result of installing an executable instead of a
> module.
> Your solutions are really interesting, and while I already knew about
> par and docker, fatpack has been an interesting hint, but I'm looking
> for something simpler.
> 
> Luca
> 

Hi Luca!

I think you should take a look at Dist-Zilla ( http://dzil.org/ ;
https://github.com/rjbs/dist-zilla/ ; https://metacpan.org/release/Dist-Zilla )
which seems to be what most modern Perl developers prefer. You can use it for
executables using https://metacpan.org/pod/Dist::Zilla::Plugin::ExecDir .

Also note that I started working on
https://github.com/shlomif/dzil-dist-ini-format-documentation but it may be
lacking in part because there are several layers to the dist.ini parser and my
breadcrumbs trail was getting longer.

Regards,

Shlomi Fish


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