As a Linux administrator, you should know how to add, delete and grant sudo privileges to users. Sometimes, you may give temporary sudo access to regular users for specific tasks like software installation or administrative work. Over the time, you might forget to revoke the sudo privileges. To ensure security, it's a good practice to periodically check for super users with sudo access on your Linux system. If you find any forgotten or unnecessary sudo access, you can simply revoke them. This brief guide explains how to find all sudo users in Linux and Unix-like operating systems.
Table of Contents
Display All Users
Let us first list all users in the system. To do so, run:
$ awk -F':' '{ print $1}' /etc/passwd
Sample output from my Ubuntu system:
root daemon bin sys sync games man lp mail news uucp proxy www-data backup list irc gnats nobody systemd-timesync systemd-network systemd-resolve systemd-bus-proxy syslog _apt lxd messagebus uuidd dnsmasq sshd sk senthil kumar ostechnix
Another way to list all users in a Linux system is:
$ compgen -u
For more methods to display all users in Linux, check the following guide.
How To List All Users In Linux
List Sudo Users in Linux
In most Linux distributions, members of the "sudo" or "wheel" group are granted sudo privileges. To see the members of the "sudo" group, you can use the getent command or simply list the contents of the /etc/group file:
To find all sudo or super users in Linux, use getent command like below:
$ getent group sudo
Sample output:
sudo:x:27:sk,ostechnix
Explanation of the output:
- sudo: This is the name of the group. In this case, it is the sudo group, which typically grants members sudo (superuser) privileges.
- x: This field represents the group password, which is usually not used in modern Linux systems. Hence, it is typically set to "x" or a placeholder.
- 27: This is the group ID (GID) assigned to the sudo group.
- sk,ostechnix: These are the members of the sudo group.
In summary, the output shows information about the sudo group, its group ID, and users called "sk" and "ostechnix" who has sudo privileges on the system. This user can perform administrative tasks using the sudo command.
Alternatively, you can identify all sudo users by listing the contents of the /etc/group file:
$ cat /etc/group | grep '^sudo:' sudo:x:27:sk,ostechnix
As you see in the above output, "sk" and "ostechnix" are the sudo users in my system.
You can get the simplified output by excluding other parameters and listing only the names of the sudo users like below.
$ getent group sudo | cut -d: -f4 sk,ostechnix
Let us break down the command and see what each parameter does.
The above command is a combination of two Linux commands:
- getent group sudo: This command retrieves information about the "sudo" group from the system's database. The getent utility is used to query the Name Service Switch (NSS) databases, and in this case, it fetches the details of the "sudo" group.
- cut -d: -f4: The output of the previous command is then piped (represented by the | symbol) to the cut command, which is used to extract specific fields from the input data. In this case, it splits each line of input using the ":" character as the delimiter (-d:), and it selects the fourth field (-f4).
So, the purpose of this command is to retrieve and display the list of user IDs (UIDs) that are members of the "sudo" group.
Each line in the output represents a user ID that belongs to the "sudo" group. The user IDs listed in the output are typically used to map the users to their respective names in the /etc/passwd file.
You can also use "grep" command to filter the names of the sudo users from the file /etc/group and get the same result as the previous command.
$ grep '^sudo:.*$' /etc/group | cut -d: -f4 sk,ostechnix
As mentioned earlier, being a member of the sudo group allows the user to execute commands with elevated privileges using the sudo command.
Find if an User has Sudo Privileges
We know now how to find all sudo users in our Linux system. How to find whether a certain user has sudo privilege or not? It's easy to check individual user sudo access!
If you want to check sudo access for a specific user, you can use the sudo -l command:
$ sudo -l -U sk
This command will help you to find if an user is sudo user or not.
Sample output:
Matching Defaults entries for sk on ubuntuserver: env_reset, mail_badpass, secure_path=/usr/local/sbin\:/usr/local/bin\:/usr/sbin\:/usr/bin\:/sbin\:/bin\:/snap/bin User sk may run the following commands on ubuntuserver: <strong> (ALL : ALL) ALL</strong>
As you see, the user named "sk" can perform all commands. So, he is in the sudo group.
Let us check another user.
$ sudo -l -U senthil
Sample output:
User <strong>senthil is not allowed to run sudo</strong> on ubuntuserver.
Well, the user "senthil" is not allowed to run sudo. He is just a regular user!
We can also find if an user has sudo access by running the following command:
$ sudo -nv
If the output shows nothing, the user has sudo access.
If you see an output like below, then the user doesn't has sudo access.
$ sudo -nv Sorry, user <strong>senthil may not run sudo</strong> on ubuntuserver.
Frequently Asked Questions
Q: What are sudo users in Linux?A: In Linux, sudo users are regular users who have been granted special privileges to perform administrative tasks. They can use the "sudo" command to temporarily elevate their privileges and execute commands as a superuser (root) without logging in as the root user.
Q: How can I find all sudo users on my Linux system?A: You can find all sudo users in Linux using different methods. One way is by checking the "sudo" group in the /etc/group file using the following command:cat /etc/group | grep '^sudo:'This will display a list of users who are members of the "sudo" group, typically having sudo access.
Q: Can I use the "sudo -l" command to find sudo users?A: While the sudo -l command is useful to check the sudo privileges of a specific user, it does not directly provide a comprehensive list of all sudo users on the system. It's more suitable for verifying an individual user's sudo permissions.
Q: Why is it important to find sudo users on a Linux system?A: It is essential to periodically check for sudo users on a Linux system to ensure security and proper privilege management. Over time, temporary sudo access might be forgotten or not revoked, potentially leading to security risks. By identifying all sudo users, administrators can review and control who has elevated privileges on the system.
Q: Is it possible to check sudo users in Unix-like systems other than Linux?A: Yes, the same approach can be used to check for sudo users on Unix-like systems, such as macOS, FreeBSD, or other UNIX-based operating systems. The sudoers file and group configuration may differ slightly, but the general method remains similar.
Conclusion
By knowing how to find all sudo users in Linux, you can better manage sudo access on your system. This can help to ensure that only authorized users have access to sudo privileges, and that sudo access is not being abused.
I hope this helps.
Suggested Read:
- How To List The Members Of A Group In Linux
- How To Grant And Remove Sudo Privileges To Users On Ubuntu
- How To Change Default Sudo Log File In Linux
- How To Restore Sudo Privileges To A User
- How To Run Particular Commands Without Sudo Password In Linux
以上是如何在Linux中找到所有Sudo用户的详细内容。更多信息请关注PHP中文网其他相关文章!

Linux 命令行界面提供了丰富的文本处理工具,其中最强大的工具之一是 sed 命令。sed 是 Stream EDitor 的缩写,是一个多功能工具,允许对文本文件和流进行复杂的处理。 什么是 Sed? sed 是一款非交互式文本编辑器,它操作管道输入或文本文件。通过提供指令,您可以让它修改和处理文件或流中的文本。sed 最常见的用例包括选择文本、替换文本、修改原始文件、向文本添加行或从文本中删除行等操作。它可以在 Bash 和其他命令行 shell 中从命令行使用。 Sed 命令语法 sed

Linux:现代计算的基石,从智能手机到超级计算机,无所不能。多年来,Linux内核的规模和复杂性显着增长。截至2025年1月,Linux内核源代码大约包含4000万行代码!这是开源、社区驱动项目历史上最伟大的成就之一。 本文将讨论Linux内核源代码行数的指数级增长,其原因以及如何自行检查当前行数。 目录 - Linux内核的历程 统计Linux内核源代码的行数 只统计C和头文件 内核增长的指数趋势 验证历史Linux内核行数 总结 Linux内核的历程 自1991年Linus Tor

Discover Pillet:一种复古的,开源的迷你计算机 寻找将经典风格与尖端技术融合的迷你计算机? Meet Pilet是一个由Raspberry Pi 5的模块化的开源奇迹。拥有7小时的电池寿命

有效地计数Linux中的文件和文件夹:综合指南 知道如何快速计算Linux中的文件和目录对于系统管理员和管理大型数据集的任何人至关重要。本指南使用简单命令l演示

Liquorix内核:提升Linux系统性能的利器 Linux以其灵活、安全和高性能而闻名,成为开发人员、系统管理员和高级用户的首选操作系统。然而,通用Linux内核并非总是能满足寻求最大性能和响应速度用户的需求。这就是Liquorix内核发挥作用的地方——一个针对性能优化的替代方案,有望增强您的Linux系统。本文将探讨Liquorix内核是什么,为什么您可能想要使用它,以及如何安装和配置它以充分发挥系统的性能。 Liquorix内核详解 Liquorix内核是一个预编译的Linux内核,专为

System76 Meerkat:强大的迷你PC 寻找一台功能强大但节省空间的计算机? 与System76结识Meerkat Mini PC!这个紧凑型强国非常适合整理台式机和苛刻的任务。 目录 - 紧凑的设计,令人印象深刻

在当今数字时代,数据不仅仅是信息,更是我们生活的一部分。从照片和文档到敏感的个人信息,我们的数据代表着我们的回忆、工作和兴趣。虽然云存储服务广泛可用,但它们通常伴随着隐私问题、订阅费用和定制限制。这就是在Ubuntu上构建个人云作为强大替代方案的意义所在,它使您可以完全控制自己的数据,并灵活地根据需要进行自定义和扩展。 本指南将引导您设置基于Ubuntu的个人云,使用Nextcloud作为主要应用程序,并确保您的设置安全可靠。 为什么在Ubuntu上构建个人云? Ubuntu是最流行的Linux

有效管理用户帐户和组成员资格对于Linux/UNIX系统管理至关重要。 这样可以确保适当的资源和数据访问控制。 本教程详细介绍了如何将用户添加到Linux和Unix系统中的多个组中。 我们


热AI工具

Undresser.AI Undress
人工智能驱动的应用程序,用于创建逼真的裸体照片

AI Clothes Remover
用于从照片中去除衣服的在线人工智能工具。

Undress AI Tool
免费脱衣服图片

Clothoff.io
AI脱衣机

AI Hentai Generator
免费生成ai无尽的。

热门文章

热工具

Dreamweaver CS6
视觉化网页开发工具

SecLists
SecLists是最终安全测试人员的伙伴。它是一个包含各种类型列表的集合,这些列表在安全评估过程中经常使用,都在一个地方。SecLists通过方便地提供安全测试人员可能需要的所有列表,帮助提高安全测试的效率和生产力。列表类型包括用户名、密码、URL、模糊测试有效载荷、敏感数据模式、Web shell等等。测试人员只需将此存储库拉到新的测试机上,他就可以访问到所需的每种类型的列表。

螳螂BT
Mantis是一个易于部署的基于Web的缺陷跟踪工具,用于帮助产品缺陷跟踪。它需要PHP、MySQL和一个Web服务器。请查看我们的演示和托管服务。

mPDF
mPDF是一个PHP库,可以从UTF-8编码的HTML生成PDF文件。原作者Ian Back编写mPDF以从他的网站上“即时”输出PDF文件,并处理不同的语言。与原始脚本如HTML2FPDF相比,它的速度较慢,并且在使用Unicode字体时生成的文件较大,但支持CSS样式等,并进行了大量增强。支持几乎所有语言,包括RTL(阿拉伯语和希伯来语)和CJK(中日韩)。支持嵌套的块级元素(如P、DIV),

ZendStudio 13.5.1 Mac
功能强大的PHP集成开发环境