I feel like this question has been asked in the past but I could not find it in the search.

So I am running this code snippet from Dave Cross' blog titled, Summarizing a Month of Git Activity with Perl (and a Little Help from AI) and I ran into a new feature of Perl -- subroutines that take named arguments. We had prototypes in the past but people said they were wonky so I avoided them for the most part.

So here I am trying to use this thing and I start getting a weird error:

#!/usr/bin/perl -w
use strict;

# LEARN: weird -- the method has named parameters ... since v5.36

sub commits_for_month ($repo, $since, $until) {
  my $cmd = sprintf(
    q{git -C %s log --since="%s" --until="%s" --pretty=format:"%%s"},
    $repo, $since, $until
  );

  my @commits = `$cmd`;
  chomp @commits;

  return @commits;
}

1;
[download]

I get...,

llegal character in prototype for main::commits_for_month : $repo, $si
+nce, $until at ./gitter.pl line 7.
Global symbol "$repo" requires explicit package name (did you forget t
+o declare "my $repo"?) at ./gitter.pl line 10.
Global symbol "$since" requires explicit package name (did you forget 
+to declare "my $since"?) at ./gitter.pl line 10.
Global symbol "$until" requires explicit package name (did you forget 
+to declare "my $until"?) at ./gitter.pl line 11.
./gitter.pl had compilation errors.
[download]

My Perl version:

This is perl 5, version 40, subversion 1 (v5.40.1) built for x86_64-li
+nux-thread-multi
...
[download]

When I look this up using Google's handy-dandy AI it tells me all about the normal way to get passed-in parameters in a subroutine and then tells me that this new syntax is available in v5.36. So I add,

use v5.36;
[download]

To my code and voila, the code compiles,

 perl -c ./gitter.pl
./gitter.pl syntax OK
[download]

Dave's example didn't specify the version like this in his code. Is there something in my environment I am supposed to set to avoid this from happening?

I tried installing Test2::Harness and a couple tests failed. I am not totally understanding the output and if someone knowledgeable could interpret this for me I'd be grateful.

Running make test for EXODIST/Test2-Harness-1.000170.tar.gz
PERL_DL_NONLAZY=1 "/usr/bin/perl.exe" "-Iblib/lib" "-Iblib/arch" test.pl

  FAIL    job 46  +~find_in_updir
  PASS    job 46    + Found file in expected spot
  FAIL    job 46    + Found file in expected spot
  DEBUG   job 46    | t/unit/App/Yath/Util.t line 133
(  DIAG  )  job 46    | +---------+----+-----------------------------------------------------------+
(  DIAG  )  job 46    | | GOT     | OP | CHECK                                                     |
(  DIAG  )  job 46    | +---------+----+-----------------------------------------------------------+
(  DIAG  )  job 46    | | <UNDEF> | =~ | (?^:\/cygdrive\/c\/Users\/somia\/AppData\/Local\/Temp\/ya |
(  DIAG  )  job 46    | |         |    | th\-149000\-j3p7oZ\/tmp\/FJbCQG\/17DQP5yPmV\/thefile$)    |
(  DIAG  )  job 46    | +---------+----+-----------------------------------------------------------+
  PLAN    job 46    | Expected assertions: 2
            job 46    ^
(  DIAG  )  job 46    Failed test 'find_in_updir'
(  DIAG  )  job 46    at t/unit/App/Yath/Util.t line 134.

-------------------------------------------------------------------------------------------

  FAIL    job 57  + /cygdrive/c/Users/somia/AppData/Local/Temp has correct permissions
  DEBUG   job 57    t2/tmp_perms.t line 36

The following jobs failed at least once:
+--------------------+-----------+--------------------+--------------------+
| Job ID             | Times Run | Test File          | Succeeded Eventual |
|                    |           |                    | ly?                |
+--------------------+-----------+--------------------+--------------------+
|                    |           |                    |                    |
| 796D54CF-8067-1014 | 2         | t/unit/App/Yath/Ut | NO                 |
| -B37C-A366FD41E411 |           | il.t               |                    |
|                    |           |                    |                    |
| 7973C25C-8067-1014 | 2         | t2/tmp_perms.t     | NO                 |
| -B37C-A366FD41E411 |           |                    |                    |
+--------------------+-----------+--------------------+--------------------+

The following jobs failed:
+---------------------------------+------------------------+---------------+
| Job ID                          | Test File              | Subtests      |
+---------------------------------+------------------------+---------------+
| 796D54CF-8067-1014-B37C-A366FD4 | t/unit/App/Yath/Util.t | find_in_updir |
| 1E411                           |                        |               |
|                                 |                        |               |
| 7973C25C-8067-1014-B37C-A366FD4 | t2/tmp_perms.t         |               |
| 1E411                           |                        |               |
+---------------------------------+------------------------+---------------+

                                    Yath Result Summary
-------------------------------------------------------------------------------------------
     Fail Count: 2
     File Count: 91
Assertion Count: 1996
      Wall Time: 632.81 seconds
       CPU Time: 1960.39 seconds (usr: 3.67s | sys: 1.70s | cusr: 459.45s | csys: 1495.57s)
      CPU Usage: 309%
    -->  Result: FAILED  <--

yath exited with 256 yath exited with 256
not ok 1 - Passed tests when run by yath (allow fork)
not ok 2 - Passed tests when run by yath (no fork)

-------------------------------------------------------------------------------------------

My Perl and System characteristics:

cygwin_nt-10.0-26200 - 3.7.0
AMD Ryzen 5 4600H with Radeon Graphics (AuthenticAMD 3000MHz) x86_64
Perl (/usr/bin/perl:
This is perl 5, version 40, subversion 3 (v5.40.3) built for x86_64-cygwin-threads-multi

Thanks, all.
    – Soren
Apr 15, 2026 at 18:38 UTC

% perl -MHTTP::Tiny -MJSON::PP -le 'print decode_json(HTTP::Tiny->new-
+>get("https://fastapi.metacpan.org/v1/module/" . shift)->{content})->
+{version}' Encode     
3.21

perl -MHTTP::Tiny -MJSON::PP -le 'print decode_json(HTTP::Tiny->new->g
+et("https://fastapi.metacpan.org/v1/module/" . shift)->{content})->{v
+ersion}' Config
<NOTHING GETS PRINTED>
[download]

fastapi.metacpan.org/v1/module/Encode 

{ "abstract" : "character encodings in Perl"...

fastapi.metacpan.org/v1/module/Config

{ "code" : 404, "message" : "Not found" }
[download]

% perl -MExtUtils::Installed -le 'print for ExtUtils::Installed->new->
+files("Catalyst")'
Catalyst is not installed at -e line 1.

% perl -MModule::Metadata -le 'print Module::Metadata->new_from_module
+("Catalyst")->{filename}'                  
/perl5/perlbrew/perls/perl-5.42.0/lib/site_perl/5.42.0/Catalyst.pm
[download]

% perl -MExtUtils::Installed -le 'print ExtUtils::Installed->new->pack
+list("CGI")->packlist_file'     
/perl5/perlbrew/perls/perl-5.42.0/lib/site_perl/5.42.0/darwin-2level/a
+uto/CGI/.packlist

ls -l /perl5/perlbrew/perls/perl-5.42.0/lib/site_perl/5.42.0/darwin-2l
+evel/auto/CGI

-rw-r--r--    1 user  staff   1.3K Jan  2 00:34 .packlist
drwxr-xr-x    3 user  staff    96B Jan 10 05:23 Ajax
drwxr-xr-x    3 user  staff    96B Jan 10 05:24 Application
drwxr-xr-x    3 user  staff    96B Jan 10 05:32 Compress
drwxr-xr-x    3 user  staff    96B Jan 10 05:33 PSGI
drwxr-xr-x    3 user  staff    96B Jan 10 05:33 Prototype
drwxr-xr-x    3 user  staff    96B Dec 17 11:39 Simple
drwxr-xr-x    3 user  staff    96B Dec 17 11:39 Struct
drwxr-xr-x    3 user  staff    96B Dec 17 11:39 Wiki

% ls -l /perl5/perlbrew/perls/perl-5.42.0/lib/site_perl/5.42.0/darwin-
+2level/auto/Catalyst            

drwxr-xr-x    4 user  staff   128B Apr 15 07:00 Action
drwxr-xr-x    4 user  staff   128B Apr 15 07:00 Controller
drwxr-xr-x    3 user  staff    96B Dec 17 11:46 Devel
drwxr-xr-x    4 user  staff   128B Apr 15 07:00 Engine
drwxr-xr-x    3 user  staff    96B Dec 17 11:46 Manual
drwxr-xr-x    5 user  staff   160B Dec 17 11:46 Plugin
drwxr-xr-x    3 user  staff    96B Dec 17 11:45 Runtime
[download]

% perlbrew install -v perl-5.8.9
...
DB_File.xs:998:34: error: incompatible function pointer types assignin
+g to 'u_int32_t (*)(const void *, size_t)' (aka 'unsigned int (*)(con
+st void *, unsigned long)') from 'int (const void *, size_t)' (aka 'i
+nt (const void *, unsigned long)') [-Wincompatible-function-pointer-t
+ypes]
                info->db_HA_hash = hash_cb ;
                                 ^ ~~~~~~~
DB_File.xs:1041:36: error: incompatible function pointer types assigni
+ng to 'size_t (*)(const DBT *, const DBT *)' (aka 'unsigned long (*)(
+const DBT *, const DBT *)') from 'int (const DBT *, const DBT *)' [-W
+incompatible-function-pointer-types]
                info->db_BT_prefix = btree_prefix ;
                                   ^ ~~~~~~~~~~~~
...
308 warnings and 2 errors generated.
make[1]: *** [DB_File.o] Error 1
make: *** [lib/auto/DB_File/DB_File.bundle] Error 2
perl-5.8.9 is successfully installed.

% perlbrew list
* perl-5.42.0                               
  perl-5.38.2   

% perlbrew install -v perl-5.24.4
...
# Failed test 25 - SHA for cpan/ExtUtils-MakeMaker/lib/ExtUtils/Liblis
+t/Kid.pm matches stashed SHA at porting/customized.t line 105
#      got "47d2fdf890d7913ccd0e32b5f98a98f75745d227"
# expected "bfd2aa00ca4ed251f342e1d1ad704abbaf5a615e"
porting/customized.t .............................................. 
Failed 1/181 subtests 
...
Test Summary Report
-------------------
porting/customized.t                                            (Wstat
+: 0 Tests: 181 Failed: 1)
  Failed test:  25
porting/libperl.t                                               (Wstat
+: 7424 Tests: 0 Failed: 0)
  Non-zero exit status: 29
  Parse errors: No plan found in TAP output
Files=2410, Tests=850611, 515 wallclock secs (11.99 usr  2.72 sys + 13
+4.39 cusr 16.64 csys = 165.74 CPU)
Result: FAIL
make: *** [test_harness] Error 1
perl-5.24.4 is successfully installed.

% perlbrew list                       
* perl-5.42.0                               
  perl-5.38.2
[download]

Summary of my perl5 (revision 5 version 42 subversion 0) configuration:
   
  Platform:
    osname=darwin
    osvers=23.3.0
    archname=darwin-2level
    gccversion='Apple LLVM 15.0.0 (clang-1500.3.9.4)'

    PERLBREW_PERL="perl-5.42.0"
    PERLBREW_SHELLRC_VERSION="1.02"
    PERLBREW_VERSION="1.02"

I have a fairly complex regexp, consisting of 9 match groups one of which has to match. I'm using copies of the exact same regexp in 4 different spots. All of them should match the same text. However, in one spot I want to access the match parameters as in $1 to $9, while in the other spots only one parameter ($3) and $`, $&, and $' are used.

How do I abstract a regexp so I only need to define and update it in one spot, but still be able to access the capture match groups anyway?

I tried storing the regexp pattern in a string variable then use that variable in the search, but I don't know how to correctly set the variable to a multi-line string (using a here document?) and use that for the pattern. Below is a dump of the working code, then the failing code and the error messages:

            while (not $second and $linking =~
              /(\bINT\s?[0-9A-Fa-f]{2}[Hh]?
                (?:\/(?:E?[ABCD][XHL]|E?[SD]I|E?[SB]P|[DESC]S)=[0-9A-F
+a-f]{2,}[Hh]?)+
                (?:\"[^"]+\")?
               )
              |(\bINT\s?[0-9A-Fa-f]{2}[Hh]?
                (?:\"[^"]+\")?
               )
              |(\b(?:E?A[XHL])=[0-9A-Fa-f]{2,}[Hh]?
                (?:\/(?:E?[ABCD][XHL]|E?[SD]I|E?[SB]P|[DESC]S)=[0-9A-F
+a-f]{2,}[Hh]?)*
                (?:\"[^"]+\")?
               )
              |(\#[0-9A-Z][0-9]{4}\b)
              |(\bMEM\s?[0-9A-Fa-fXx]{1,4}[Hh]?:[0-9A-Fa-fXx]{1,4}[Hh]
+?
                (?:\"[^"]+\")?
               )
              |(\bMEM\s?[0-9A-Fa-fXx]{1,8}[Hh]?
                (?:\"[^"]+\")?
               )
              |(\@[0-9A-Fa-fXx]{1,4}[Hh]?:[0-9A-Fa-fXx]{1,4}[Hh]?
                (?:\"[^"]+\")?
               )
              |(\bPORT\s?[0-9A-Fa-fXx]{1,4}[Hh]?-[0-9A-Fa-fXx]{1,4}[Hh
+]?
                (?:\"[^"]+\")?
               )
              |(\bPORT\s?[0-9A-Fa-fXx]{1,4}[Hh]?
                (?:\"[^"]+\")?
               )
              /x) {
              my $intplus = $1;
              my $intonly = $2;
              my $regonly = $3;
              if (defined $regonly and not defined $int) {
                if (defined $link) {
                  print_or_errorline("Entered reg only link without im
+plicit INT");
                  return;
                }
                $maskhighlight .= " " x (length($`) + length($&));
                $linking = $';
                next;
              }
              my $table = $4;
              my $mem_16_16 = $5;
              my $mem_32 = $6;
              my $call = $7;
              my $portrange = $8;
              my $portsingle = $9;
              $maskhighlight .= " " x length $`;
[download]

            my $linkpattern = <<PATTERNEND;
              (\bINT\s?[0-9A-Fa-f]{2}[Hh]?
                (?:\/(?:E?[ABCD][XHL]|E?[SD]I|E?[SB]P|[DESC]S)=[0-9A-F
+a-f]{2,}[Hh]?)+
                (?:\"[^\"]+\")?
               )
              |(\bINT\s?[0-9A-Fa-f]{2}[Hh]?
                (?:\"[^\"]+\")?
               )
              |(\b(?:E?A[XHL])=[0-9A-Fa-f]{2,}[Hh]?
                (?:\/(?:E?[ABCD][XHL]|E?[SD]I|E?[SB]P|[DESC]S)=[0-9A-F
+a-f]{2,}[Hh]?)*
                (?:\"[^\"]+\")?
               )
              |(\#[0-9A-Z][0-9]{4}\b)
              |(\bMEM\s?[0-9A-Fa-fXx]{1,4}[Hh]?:[0-9A-Fa-fXx]{1,4}[Hh]
+?
                (?:\"[^\"]+\")?
               )
              |(\bMEM\s?[0-9A-Fa-fXx]{1,8}[Hh]?
                (?:\"[^\"]+\")?
               )
              |(\@[0-9A-Fa-fXx]{1,4}[Hh]?:[0-9A-Fa-fXx]{1,4}[Hh]?
                (?:\"[^\"]+\")?
               )
              |(\bPORT\s?[0-9A-Fa-fXx]{1,4}[Hh]?-[0-9A-Fa-fXx]{1,4}[Hh
+]?
                (?:\"[^\"]+\")?
               )
              |(\bPORT\s?[0-9A-Fa-fXx]{1,4}[Hh]?
                (?:\"[^\"]+\")?
               )
PATTERNEND
            while (not $second and $linking =~
              /$linkpattern/x) {
              my $intplus = $1;
              my $intonly = $2;
              my $regonly = $3;
              if (defined $regonly and not defined $int) {
                if (defined $link) {
                  print_or_errorline("Entered reg only link without im
+plicit INT");
                  return;
                }
                $maskhighlight .= " " x (length($`) + length($&));
                $linking = $';
                next;
              }
              my $table = $4;
              my $mem_16_16 = $5;
              my $mem_32 = $6;
              my $call = $7;
              my $portrange = $8;
              my $portsingle = $9;
              $maskhighlight .= " " x length $`;
[download]

Unrecognized escape \s passed through at /home/[user]/proj/tractest/in
+tlist.pl line 419.
Unrecognized escape \s passed through at /home/[user]/proj/tractest/in
+tlist.pl line 419.
Unrecognized escape \s passed through at /home/[user]/proj/tractest/in
+tlist.pl line 419.
Unrecognized escape \s passed through at /home/[user]/proj/tractest/in
+tlist.pl line 419.
Unrecognized escape \s passed through at /home/[user]/proj/tractest/in
+tlist.pl line 419.
Unrecognized escape \s passed through at /home/[user]/proj/tractest/in
+tlist.pl line 419.
Unmatched ( in regex; marked by <-- HERE in m/              INTs?[0-9A
+-Fa-f]{2}[Hh]?
                (?:/(?:E?[ABCD][XHL]|E?[SD]I|E?[SB]P|[DESC]S)=[0-9A-Fa
+-f]{2,}[Hh]?)+
                (?:"[^"]+")?
               )
              |INTs?[0-9A-Fa-f]{2}[Hh]?
                (?:"[^"]+")?
               )
              |(?:E?A[XHL])=[0-9A-Fa-f]{2,}[Hh]?
                (?:/(?:E?[ABCD][XHL]|E?[SD]I|E?[SB]P|[DESC]S)=[0-9A-Fa
+-f]{2,}[Hh]?)*
                (?:"[^"]+")?
               )
              |(#[0-9A-Z][0-9]{4)
               <-- HERE |MEMs?[0-9A-Fa-fXx]{1,4}[Hh]?:[0-9A-Fa-fXx]{1,
+4}[Hh]?
                (?:"[^"]+")?
               )
              |MEMs?[0-9A-Fa-fXx]{1,8}[Hh]?
                (?:"[^"]+")?
               )
              |(@[0-9A-Fa-fXx]{1,4}[Hh]?:[0-9A-Fa-fXx]{1,4}[Hh]?
                (?:"[^"]+")?
               )
              |PORTs?[0-9A-Fa-fXx]{1,4}[Hh]?-[0-9A-Fa-fXx]{1,4}[Hh]?
                (?:"[^"]+")?
               )
              |PORTs?[0-9A-Fa-fXx]{1,4}[Hh]?
                (?:"[^"]+")?
               )
/ at /home/[user]/proj/tractest/intlist.pl line 447, <$array_lstff[...
+]> line 197305.
[download]

I have an NFS file system mounted on many machines. I am attempting to use file locking to get exclusive access by one system to a file. The critical code section shown here:

        # loop through file names looking for one we can lock
        open ( my $file_handle, '+<', $file_name ) or next;
        if ( !flock( $file_handle, LOCK_EX | LOCK_NB ) ) {
            close( $file_handle );
            next;
        }
        # do some work here based on the file contents
        unlink $file_name;
        close( $file_handle );
[download]

This almost always works, but occasionally there is a failure where two machines get a lock on the same file. It appears there is a race between unlinking (deleting) the file and releasing the lock. It seems like there is a small window where the lock is actually released before the file is deleted allowing another machine to lock and read the file before it is deleted.

I am wondering if this is a known problem and if there is a preferred way to work around this.

Been a lurker since ~2k and an active member since ~2k9. Threw a question to "AI" the other day to write a script to safely allow me to update an iptables chain that I need to implement remotely. The result is below. My question for the monks isn't a question. It's a request from an old timer to see if there are any newcomers who can rewrite this script in Perl, properly.

#!/bin/sh
# apply-new-iptables.sh
OLD=/root/iptables-old.rules
NEW=/root/iptables-new.rules
# backup current
iptables-save > "$OLD"
# apply new rules
iptables-restore < "$NEW"
# start rollback timer: restore OLD after 60s if not canceled
( sleep 60 && iptables-restore < "$OLD" ) &
ROLLBACK_PID=$!
echo $ROLLBACK_PID > /tmp/iptables-rollback.pid
echo "New rules applied. To keep them, run: kill $(cat /tmp/iptables-r
+ollback.pid) && rm /tmp/iptables-rollback.pid"
[download]

Hint: there is at least one hugely fundamental issue that AI hallucinated.

-stevieb

Update: Hablo español si prefieres.

Using SIOCGIFCONF looks like an interesting alternative, but the only perl example I found is very non-portable: Re: How do I get the local internet IP address?. sys/ioctl.ph isn't present in any of my perlbrewed perls, and even after running h2ph, it fails with "unsupported architecture" for macOS. But I did confirm with the following C program that SIOCGIFCONF is relatively portable when implemented right: https://gist.github.com/OrangeTide/909204.

Is there an alternative I missed?

Hello.

I am reading a .docx file in Russian. The code $text =~ s/^Испытательная(.*?)/\1/ug; is supposed to process a line by removing part of the text. If the text is written in English, everything is detected and trimmed correctly, but I cannot get it to work with Russian text. In the console, instead of Russian text, I see garbled characters. I've been dancing around encodings — utf8, utf16, cp1251, cp1252 — but none of them give the desired result. Apparently, I am doing something wrong.

Important! When the text is written to a text file from the Word document, it displays correctly.

I would appreciate your help. Thank you.

#!/usr/bin/perl
use Win32::OLE;
use Win32::OLE::Enum;
use utf8;
use strict;

my $text;
my $paragraph;

my $document = Win32::OLE -> GetObject($ARGV[1]);
open (FH,">$ARGV[0]") || die "Can't open file: $!\n";

my $paragraphs = $document->Paragraphs();
my $enumerate = new Win32::OLE::Enum($paragraphs);
while(defined($paragraph = $enumerate->Next()))
{
    $text = $paragraph->{Range}->{Text};
    $text =~ s/^Испытат&#107
+7;льная(.*?)/\1/ug;
    $text =~ s/[\n\r]//g;
    print FH "$text\n";
}
[download]