In Linux systems, there are two commonly used commands for switching user identities and performing privileged operations, they are su and sudo. Although they can both achieve privilege escalation, there are some differences in terms of usage, security, and applicable scenarios. This article will introduce the difference between su and sudo commands to help users choose and use these two commands correctly.
1. su command
The su (switch user) command is a command to switch to another user identity in a Linux system. Usually, it requires the superuser (root) password to switch to other users. When using the su command, the user can switch to another user's account and obtain the permissions of that account. For example, you can switch to superuser (root) using the following command:
su
After entering the password, the user will switch to the root user and gain the root user's permissions.
2. sudo command
The sudo (execute command as superuser) command is a command that executes specific commands with superuser (root) privileges in a Linux system. Unlike the su command, the sudo command allows ordinary users to perform privileged operations with their own passwords without knowing the superuser's password. When using the sudo command, users need to add the sudo keyword before the command and enter their password to confirm their identity.
For example, the following command will execute the apt-get update command with superuser privileges:
sudo apt-get update
After entering the password, the user is granted permission to perform privileged operations.
3. Differences and comparisons
3.1 User identity
The su command requires the superuser (root) password, and users can switch to the identity of other users and gain their permissions. The sudo command allows ordinary users to perform privileged operations with their own passwords.
3.2 Scope of authority
After using the su command to switch to another user, the user will obtain all the permissions of that user. The sudo command can control the scope of privileged operations through configuration files (sudoers files), and can accurately specify which commands a user can execute and as which users.
3.3 Security
Since the su command requires a shared root password, this may present some security risks. If someone else knows the root password, they can switch to the root user and have full control of the system. The sudo command can avoid sharing the root password and improve system security by using its own password to perform privileged operations.
3.4 Recording logs
The sudo command logs every privileged operation, including the command executed and the identity of the executor. This helps system administrators with security auditing and tracking. The su command does not have a built-in logging function and cannot track user switching and commands executed.
3.5 How to use
The su command can be entered directly in the command line, and then the password of the target user can be entered to switch users. The sudo command requires the sudo keyword before the command, and then enter your password to confirm your identity.
4. Applicable scenarios
-
Using the su command to switch users is suitable for situations where you need to operate as another user for a long time, such as executing a series of commands in the environment of other users or working for a long time.
-
Use the sudo command for situations where you temporarily need to perform privileged operations, such as installing software, updating the system, or performing important system maintenance tasks.
5 Conclusion
The su command and sudo command are commonly used commands in Linux systems to switch user identities and perform privileged operations. There are some differences between them in terms of usage, safety and applicable scenarios. The su command requires the superuser password to switch user identities, while the sudo command allows ordinary users to perform privileged operations with their own password.
Using the sudo command can avoid sharing the root password and logging privileged operations, improving system security and traceability. When choosing between using the su command or the sudo command, you need to make a choice based on your specific needs and security considerations. I hope this article will help you understand the difference between the su command and the sudo command, and enable you to correctly choose and use these two commands in actual use.