Linux su command

The Linux su (substitute user) command is used to switch to another user account in the terminal without logging out. This command allows users to perform tasks with the privileges of a different user, such as the root user. By using su, users can execute commands that require higher privileges or access files owned by another user. It is an essential tool for system administrators to carry out administrative tasks securely.

su Syntax:

su [option] [username]

Options:

Option	Description
-c	Command to execute
-l	Simulate a full login
-m	Simulate a full login
-s	Shell to use (default /bin/sh)

Parameters:

Parameter	Description
username	The user to switch to

Caution

Be cautious when using the su command as it allows you to switch to another user account, potentially granting you access to sensitive information and actions that may have security implications.

su Usage:

Switch to Root User

su

This command allows you to switch to the root user by entering the root password.

Change to Another User

su username

Used to switch to another user account by specifying the username.

Launch a Shell as Another User

su - username

Opens a shell as another user with their environment settings.

Switch User with Specific Shell

su -s /bin/bash username

Switches to another user with a specific shell (/bin/bash in this example).

Tip

Remember to use the su command with caution, as it allows you to switch to another user account, including the root account, which can have extensive permissions and capabilities. Always ensure that you have the necessary permissions to execute the su command, and be cautious when making changes to the system using this command.

How do I use su in Linux?

To use the su command in Linux, execute the following command:

su --option <value>

How do I switch to root user using su in Linux?

To switch to the root user using the su command in Linux, use the following command:

su

How do I switch to a specific user using su in Linux?

To switch to a specific user using the su command in Linux, use the following command:

su <username>

How do I login as a different user shell using su in Linux?

To login as a different user shell using the su command in Linux, use the following command:

su -s <shell> <username>

How do I preserve the environment when switching users with su in Linux?

To preserve the environment when switching users with the su command in Linux, use the following command:

su - <username>

How do I specify the login shell to use when switching users with su in Linux?

To specify the login shell to use when switching users with the su command in Linux, use the following command:

su -s <shell> <username>

How do I execute a command as another user using su in Linux?

To execute a command as another user using the su command in Linux, use the following command:

su -c "<command>" <username>

Applications of the su command

• Running commands with superuser privileges
• Switching to another user account
• Changing to a different user’s environment
• Testing user permissions and access rights