如何列出Linux组中的所有用户? [英] How to list all users in a Linux group?

问题描述

如何列出Linux中某个组的所有成员(可能还包括其他unice)?

How do I list all members of a group in Linux (and possibly other unices)?

推荐答案

不幸的是，目前尚无一种可移植的好方法，这一点据我所知.如果您尝试解析/etc/group(如其他人所建议的那样)，则会错过以该组为主要组的用户以及通过UNIX平面文件(例如LDAP，NIS， pam-pgsql等).

Unfortunately, there is no good, portable way to do this that I know of. If you attempt to parse /etc/group, as others are suggesting, you will miss users who have that group as their primary group and anyone who has been added to that group via a mechanism other than UNIX flat files (i.e. LDAP, NIS, pam-pgsql, etc.).

如果我绝对必须自己执行此操作，则可能会相反地执行此操作:使用id获取系统上每个用户的组(这将拉动所有对NSS可见的源)，并使用Perl或类似于为发现的每个组维护一个哈希表，记录该用户的成员身份.

If I absolutely had to do this myself, I'd probably do it in reverse: use id to get the groups of every user on the system (which will pull all sources visible to NSS), and use Perl or something similar to maintain a hash table for each group discovered noting the membership of that user.

当然，这给您带来了一个类似的问题:如何获取系统上每个用户的列表.由于我的位置仅使用平面文件和LDAP，因此我只能从这两个位置获取列表，但这可能对您的环境不适用.

Of course, this leaves you with a similar problem: how to get a list of every user on the system. Since my location uses only flat files and LDAP, I can just get a list from both locations, but that may or may not be true for your environment.

有人提醒我getent passwd将返回系统上所有用户的列表，包括LDAP/NIS/etc中的用户，但 getent group仍然会丢失仅通过默认组条目成为成员的用户，因此启发了我编写此快速技巧.

Edit 2: Someone in passing reminded me that getent passwd will return a list of all users on the system including ones from LDAP/NIS/etc., but getent group still will still miss users that are members only via the default group entry, so that inspired me to write this quick hack.

#!/usr/bin/perl -T
#
# Lists members of all groups, or optionally just the group
# specified on the command line
#
# Copyright © 2010-2013 by Zed Pobre ([e-mail] or [e-mail])
#
# Permission to use, copy, modify, and/or distribute this software for any
# purpose with or without fee is hereby granted, provided that the above
# copyright notice and this permission notice appear in all copies.
#

use strict; use warnings;

$ENV{"PATH"} = "/usr/bin:/bin";

my $wantedgroup = shift;

my %groupmembers;
my $usertext = `getent passwd`;

my @users = $usertext =~ /^([a-zA-Z0-9_-]+):/gm;

foreach my $userid (@users)
{
    my $usergrouptext = `id -Gn $userid`;
    my @grouplist = split(' ',$usergrouptext);

    foreach my $group (@grouplist)
    {
        $groupmembers{$group}->{$userid} = 1;
    }
}

if($wantedgroup)
{
    print_group_members($wantedgroup);
}
else
{
    foreach my $group (sort keys %groupmembers)
    {
        print "Group ",$group," has the following members:\n";
        print_group_members($group);
        print "\n";
    }
}

sub print_group_members
{
    my ($group) = @_;
    return unless $group;

    foreach my $member (sort keys %{$groupmembers{$group}})
    {
        print $member,"\n";
    }
}

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