DMARC-Filter: OpenDMARC Filter v1.4.2 delorie.com 62Q7GYuw2093433
DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 471F14BA2E10
Date: Thu, 26 Mar 2026 07:16:09 +0000
To: Soren via Cygwin <cygwin AT cygwin DOT com>
Subject: cygchk-perl-mods.pl (Was: An offering to the Perl enthusiasts .
Message-ID: <acTdORkl5-V1G71P@sdf.org>
Mail-Followup-To: Soren via Cygwin <cygwin AT cygwin DOT com>
References: <CAGB_HuT9MZCLi2Z5wQw8-6SYUddeeLLLf5_1=Yf-xH9fDzrzNw AT mail DOT gmail DOT com>
MIME-Version: 1.0
Content-Disposition: inline
In-Reply-To: <CAGB_HuT9MZCLi2Z5wQw8-6SYUddeeLLLf5_1=Yf-xH9fDzrzNw@mail.gmail.com>
User-Agent: Mutt/2.2.14 (2025-02-20)
Precedence: list
From: Dr Bean via Cygwin <cygwin AT cygwin DOT com>
Reply-To: Dr Bean <drbean AT freeshell DOT org>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Errors-To: cygwin-bounces~archive-cygwin=delorie DOT com AT cygwin DOT com
Sender: "Cygwin" <cygwin-bounces~archive-cygwin=delorie DOT com AT cygwin DOT com>

On Tue, 24 Mar 2026, Soren via Cygwin wrote:

> Greetings cygwinistas.

> I've written a program in Perl that satisfies a desire I've had for a
> while. I wanted to have a way  to check out what Perl module distributions
> have been made into cygwin packages installable with Setup, but outside of
> Setup. The main feature of how the program works is the specification of
> "namespace globs" like "IO-*" or "Module-*" used as the argument to my
> script. This allows for surveying a manageable grouping of packages from
> the Cygwin server, in the TMI (terminal, text mode interface, commandline).
> I think it's best if I just show some representative output rather than
> struggling to explain what I mean:

> $ perl ~/Scripts-working/cygchk-perl-mods.pl 'perl-Module-*'
> Matching distributions packaged for Cygwin:
> Fetching setup.ini from cygwin.com...

> perl-Module-Build           Module::Build is installed as
> /usr/local/share/perl5/site_perl/5.40/Module/Build.pm
> perl-Module-Build-Tiny      Module::Build::Tiny is installed as
> /usr/local/share/perl5/site_perl/5.40/Module/Build/Tiny.pm
> perl-Module-Build-XSUtil    Module::Build::XSUtil is installed as
> /usr/local/share/perl5/site_perl/5.40/Module/Build/XSUtil.pm
> perl-Module-Implementation  Module::Implementation is installed as
> /usr/local/share/perl5/site_perl/5.40/Module/Implementation.pm
> perl-Module-Install         Module::Install is installed as
> /usr/local/share/perl5/site_perl/5.40/Module/Install.pm
> perl-Module-Metadata        Module::Metadata is installed as
> /usr/share/perl5/5.40/Module/Metadata.pm
> perl-Module-Pluggable       Module::Pluggable is installed as
> /usr/local/share/perl5/site_perl/5.40/Module/Pluggable.pm
> perl-Module-Runtime         Module::Runtime is installed as
> /usr/local/share/perl5/site_perl/5.40/Module/Runtime.pm
> perl-Module-ScanDeps        Module::ScanDeps is installed as
> /usr/local/share/perl5/site_perl/5.40/Module/ScanDeps.pm
> perl-Module-Signature       Module::Signature is not installed

> That's how it produces output. The point of this is twofold. One is that
> there are hundreds of packaged modules in Setup and I find myself squinting
> and getting a headache if I just try to scroll through the huge list that
> matches "perl-". The other point is that the output allows me to check
> whether I've built a module from CPAN and perl has installed it under
> "site_perl/" (which has the consequence that it has precedence over modules
> installed to "vendor_perl/" [which is called "shadowing"]).

> I could possibly add features to this program: displaying the version of
> the module installed would be one nice thing. But I believe in the unix
> virtue of "small tools that do one thing well" (and I am a bit busy, yeah)
> and so for now I'll avoid feeping creaturism and just show y'all the script:

> (If you prefer to download rather than c&p I've made a gist for it at
> https://gist.github.com/somian/22f6d1baae1b44c6c1e0cb0ea867e0a5)

> #!/usr/bin/perl
> # Last modified: Tue Mar 24 11:57:45 2026

> use strict;
> use v5.18;
> use utf8;
> use warnings;
> use Carp qw/ carp croak /;
> =head1 NAME
> cygchk-perlmods.pl

> =head1 SYNOPSIS
> cygchk-perlmods.pl "IO-*"      # "glob expression"

> =head1 VERSION
> 0.10

> =head1 AUTHOR
> Soren Andersen C<somian08 AT gmail DOT com>

> =cut

> if ( @ARGV * 1 == 0 ) {
>     croak 'You must type an argument. Exiting.';
> }
> my ($globexpr) = @ARGV;
> my $as_perl_says;

> if ($globexpr !~/^perl-/) {  # you may omit the "perl-" prefix in the
> argument
>     $globexpr = 'perl-' . $globexpr;
> }

> $globexpr = lc $globexpr;
> open( my $ok_fh, '-|', "cygcheck", "-e", $globexpr);
> croak "Dying from no open on cygcheck" unless $ok_fh;

> printf( "Matching distributions packaged for Cygwin:\n" );
> my ( @dists, $mlen );
> $mlen = 0;
> while (<$ok_fh>) {
>      my $setup_name = $_;
>      my $nonly = (split( ' : ' ))[0];
>      $mlen = length($nonly) > $mlen ? length($nonly) : $mlen;
>      push @dists, $nonly;
> }
> for (@dists) {
>      my $e = substr($_,5);
>      $e =~s/-/::/g;
>      $as_perl_says = $e;
>      my $report_str = sprintf( "%-${mlen}s  %s" =>
>                               $_, $as_perl_says );
>      $report_str .=  q[ ].chk_inst( $as_perl_says );
>      say $report_str;
> }

> sub chk_inst {
>     local $::pkgname = $_[0];
>     eval qq{require $::pkgname;};
>     unless ( $@ ) {
>         my $pm = $_[0];
>         $pm =~ s{::}{/}g;
>         $pm .= '.pm';
>         return 'is installed as '. $INC{ $pm };
>     } else {
>         return 'is not installed';
>     }
> }
> __END__

> =head1 LICENSE
> This program is Free software, made available under the same terms as Perl.
> THIS PACKAGE IS PROVIDED "AS IS" AND WITHOUT ANY EXPRESS OR
> IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
> WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

> =cut

> # vim: ft=perl et sw=4 ts=4 :

I tried running this over a few outer package names in 
my system perl and perl environment manager perlbrew 
installations to see what was different in both.

I can see this also being of use in attempts to 
stick to tested cygwin perl packages and avoid taking 
chances with the 'latest and greatest' from CPAN.

The script doesn't show shadowed (hidden) modules (from 
cygwin packages) in vendor_perl (?) if there is one 
downloaded from CPAN in /usr/local/share/...?

CPAN modules may also be stored in 
/usr/share/perl5/.../site-perl?

I can see my Module::Build appears to have been installed 
from CPAN, but Module::Build::Tiny appears to have come 
from a cygwin package. That doesn't seem ideal. But is 
it no problem?

I can imagine the reason for source differences is a 
CPAN module I downloaded wanted a more recent version 
than the cygwin package provided.

But I am grateful that using perl in cygwin is 
well-ordered compared with the unavoidability of 
virtual environments in python, rendering system python 
irrelevant.

A compare-and-contrast tool like this for python 
virtual environments I could see being of use.

I will keep this around for use figuring out perl 
dependency problems when not using perlbrew.

It is not in a github or other foundry repo?

-- 
Greg "Dr Bean" Matheson		If there is one thing we learn from
http://drbean.sdf.org		studying learners, it is that
drbean AT freeshell DOT org		they learn more than we learn.

-- 
Problem reports:      https://cygwin.com/problems.html
FAQ:                  https://cygwin.com/faq/
Documentation:        https://cygwin.com/docs.html
Unsubscribe info:     https://cygwin.com/ml/#unsubscribe-simple