你可以在一个命令行中完成:

cut -d: -f1,4 /etc/passwd | grep $(getent group <groupname> | cut -d: -f3) | cut -d: -f1

上面的命令列出了所有使用groupname作为主组的用户

如果还希望列出具有groupname的用户作为次要组，则使用以下命令

getent group <groupname> | cut -d: -f4 |  tr ',' '\n'

再加上grep和tr:

$ grep ^$GROUP /etc/group | grep -o '[^:]*$' | tr ',' '\n'
user1
user2
user3

下面的命令将列出属于<your_group_name>的所有用户，但只列出由/etc/group数据库管理的用户，不包括LDAP、NIS等。它也只适用于次要组，它不会列出将该组设置为主要组的用户，因为主要组存储为/etc/passwd.文件中的GID(数字组ID)

awk -F: '/^groupname/ {print $4;}' /etc/group

下面的shell脚本将遍历所有用户，并只打印属于给定组的用户名:

#!/usr/bin/env bash
getent passwd | while IFS=: read name trash
do
    groups $name 2>/dev/null | cut -f2 -d: | grep -i -q -w "$1" && echo $name
done
true

使用的例子:

./script 'DOMAIN+Group Name'

注意:此解决方案将检查NIS和LDAP中的用户和组(不仅仅是passwd和group文件)。它还将考虑未添加到组但已将组设置为主组的用户。

编辑:为用户不属于同名组的罕见场景添加了修复。

编辑:以shell脚本的形式编写;根据@Max Chernyak aka hakunin的建议，添加了true以0状态退出;为了跳过那些偶然的组，丢弃了stderr:找不到组ID xxxxxx的名称。

Zed的实现应该扩展到其他一些主要UNIX上。

有人可以使用Solaris或HP-UX硬件吗?没有测试这些案例。

#!/usr/bin/perl
#
# Lists members of all groups, or optionally just the group
# specified on the command line
#
# Date:         12/30/2013
# Author:       William H. McCloskey, Jr.
# Changes:      Added logic to detect host type & tailor subset of getent (OSX)
# Attribution:
#   The logic for this script was directly lifted from Zed Pobre's work.
#     See below for Copyright notice.
#   The idea to use dscl to emulate a subset of the now defunct getent on OSX
#     came from
#       http://zzamboni.org/\
#         brt/2008/01/21/how-to-emulate-unix-getent-with-macosxs-dscl/
#     with an example implementation lifted from
#       https://github.com/petere/getent-osx/blob/master/getent
#
# Copyright © 2010-2013 by Zed Pobre (zed@debian.org or zed@resonant.org)
#
# 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";

# Only run on supported $os:
my $os;
($os)=(`uname -a` =~ /^([\w-]+)/);
unless ($os =~ /(HU-UX|SunOS|Linux|Darwin)/)
    {die "\$getent or equiv. does not exist:  Cannot run on $os\n";}

my $wantedgroup = shift;

my %groupmembers;

my @users;

# Acquire the list of @users based on what is available on this OS:
if ($os =~ /(SunOS|Linux|HP-UX)/) {
    #HP-UX & Solaris assumed to be like Linux; they have not been tested.
    my $usertext = `getent passwd`;
    @users = $usertext =~ /^([a-zA-Z0-9_-]+):/gm;
};
if ($os =~ /Darwin/) {
    @users = `dscl . -ls /Users`;
    chop @users;
}

# Now just do what Zed did - thanks Zed.
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";
    }
}

如果有更好的方法来分享这个建议，请告诉我;我考虑了很多方法，这就是我想到的。

不幸的是，据我所知，没有好的、可移植的方法来做到这一点。如果您尝试解析/etc/group，就像其他人建议的那样，您将会错过那些将该组作为主要组的用户，以及通过UNIX平面文件以外的机制(即LDAP、NIS、pam-pgsql等)添加到该组的任何用户。

如果我必须自己做这件事，我可能会反过来做:使用id获取系统上每个用户的组(这将拉出对NSS可见的所有源)，并使用Perl或类似的东西为发现的每个组维护一个哈希表，并指出该用户的成员。

编辑:当然，这给您留下了一个类似的问题:如何获得系统上每个用户的列表。由于我的位置只使用平面文件和LDAP，所以我只能从两个位置获得一个列表，但对于您的环境可能是这样，也可能不是这样。

编辑2:有人提醒我，getent passwd将返回系统中所有用户的列表，包括来自LDAP/NIS/等的用户。，但getent组仍然会错过仅通过默认组条目成为成员的用户，所以这激发了我写这个快速破解。

#!/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 (zed@debian.org or zed@resonant.org)
#
# 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";
    }
}