[Linux] Bash su equivalente: Switch user in the terminal

Overview

The su command in Bash allows a user to switch to another user account within the terminal. By default, it switches to the root user, enabling administrative privileges for executing commands that require elevated permissions.

Usage

The basic syntax of the su command is as follows:

su [options] [username]

If no username is specified, su defaults to the root user.

Common Options

• -l or --login: Start the shell as a login shell, which initializes the environment as if the user had logged in directly.
• -c: Execute a command as the specified user and then exit.
• -s: Specify a different shell to use instead of the default shell.
• -m or -p: Preserve the environment variables of the current user.

Common Examples

1. Switch to the root user:

   su
   

   This command prompts for the root password and switches to the root user.

2. Switch to a specific user:

   su john
   

   This command switches to the user account named “john”.

3. Execute a command as another user:

   su -c 'ls /root' john
   

   This command runs the ls /root command as user “john”.

4. Start a login shell as another user:

   su -l john
   

   This command switches to user “john” and starts a login shell, loading their environment.

5. Preserve the environment while switching users:

   su -m john
   

   This command switches to user “john” while keeping the current user’s environment variables.

Tips

• Always use su with caution, especially when switching to the root user, as it grants full control over the system.
• Consider using sudo for executing single commands with elevated privileges instead of switching users entirely.
• Remember that the su command requires the password of the target user, so ensure you have the necessary credentials.