neniro has asked for the wisdom of the Perl Monks concerning the following question:

I'm searching a way to chgrp in perl. I found chown, but it needs numerical IDs. I'm developing using Windows (yes thats odd because the target is linux) - so I tried the following code: 
#!/usr/bin/perl

use strict;
use warnings;

my $group = 'users';
my @folder = qw ( worksheets correspondence );

&chgrp($group, \@folder);

sub chgrp {
  my ($group, $folder) = @_;
  eval { system( "chgrp $group @$folder" ) };
  warn $@ if $@;
}

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It works as expected - on a Windows-system it just warns that there is no chgrp-command. Is there a better way to do this? I searched on CPAN for 'chgrp' but I found nothing.

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Re: How to chgrp in perl?
by PodMaster (Abbot) on Apr 04, 2004 at 10:56 UTC
[reply]
      The solutions i saw, searching Perlmonks, use chown and numerical-IDs. They resolve these by using getpwnam. I'd like to enhance my script, described in Using perl for creating project folders, in a way that it is possible to declare group rights in the xml-schema. It is much more flexible if i can use groupnames instead of numerical IDs.
[reply]
        getgrnam, in scalar context, returns the group ID of the named group: 
        my $gid = getgrnam("users");

        [download]
        Now you can use the chown function.

        perldoc -f getgrnam gives more detailed information about getgrnam (and its sibling functions).

        Arjen

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Re: How to chgrp in perl?
by borisz (Canon) on Apr 04, 2004 at 13:54 UTC
    You can use perl's chown to change the group.
    Boris
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Re: How to chgrp in perl?
by Vautrin (Hermit) on Apr 05, 2004 at 05:00 UTC
    If the target is a *nix system, why not just save yourself the trouble and use a chgrp command in backticks, or via a system() call. If you want to get fancy you could check the OS type or for the existence of a chgrp command in your path, and only chgrp if you know you can.
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Re: How to chgrp in perl?
by Abigail-II (Bishop) on Apr 05, 2004 at 09:20 UTC
    Nothing wrong with using system. There will always be purists who insist of writing complicated back bending C style code to avoid using system (and you can in this case, using chown and getgrnam), but they haven't seen the light yet, and don't appreciate Perls root: being a glue language.

    You could avoid the warning by checking for the OS, or the existance either /bin/chgrp or /usr/bin/chgrp (where you would find them on a UNIX system). One thing I have to ask though, what's with the eval?

    Abigail

[reply]
      I use the eval block to try and not die. It isn't necessary in this case.
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