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su – Used to Switch the Current User Identity to Another User Identity

The su command is a Linux command that stands for “substitute user” and is used to switch the current user identity to another user identity. It allows the user to temporarily assume the identity of another user without logging out and logging back in again. This command is typically used by system administrators to perform tasks that require elevated privileges.

Overview

The basic syntax of the su command is as follows:

su [options] [username]

When executed without any options or arguments, the su command will switch the user identity to the root user. The user will be prompted to enter the root user’s password. Once authenticated, the user will have access to all of the root user’s privileges and permissions.

To switch to another user’s identity, simply specify the username as an argument to the su command. For example:

su jane

This command will switch the user’s identity to the user jane. The user will be prompted to enter jane‘s password.

The su command can also be used to switch to another user’s identity and execute a command as that user. To do this, simply specify the username and command as arguments to the su command. For example:

su jane ls -l /home/jane

This command will switch the user’s identity to the user jane and execute the ls -l /home/jane command as that user.

Options

The following table lists the available options for the su command:

Option Description
-l or --login Makes the shell a login shell, which means that it will read the user’s login profile and execute any commands specified in the profile.
-c <command> Executes the specified command as the target user.

Troubleshooting Tips

  • If the user is unable to switch to another user’s identity, make sure that the target user’s password is correct.
  • If the user is unable to execute a command as the target user, make sure that the command is specified correctly and that the target user has permission to execute the command.

Notes

  • The su command should be used with caution, as it can allow the user to perform actions that could potentially harm the system.
  • When switching to the root user’s identity, it is important to be mindful of the commands that are executed, as they can have a significant impact on the system.
  • The su command is typically used by system administrators, but can also be used by regular users to switch to another user’s identity for a specific task.

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