Which linux command can be used to let you run a single command as another user?

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If you're confused about what su and sudo commands do for you, this brief guide will help you sort them out.

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Posted: March 30, 2021 |%t min read| by Bryant Son (Sudoer, Red Hat)

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This article explores the differences between the sudo and su commands in Linux. You can also watch this video to learn about these commands. Becoming root permanently with su is a well-known 'no-no' in the *nix universe. Why? Because becoming root with su means that you are root, which is the same as logging into a terminal as the root user with root's password. And that's dangerous for many reasons.

[ You might also enjoy: Linux command line basics: sudo ]

Working as root means that you have the power to:

Remove any or all files
Change the permissions of any or all files
Change the runlevel of the system
Alter user accounts
Mount or unmount filesystems
Remove or install software
Create, remove, and alter file systems

Basically, you can do anything to the system as the root user. It is the all-powerful administrative account. And, unlike other more chatty operating systems, you won't see a, "Are you sure?" dialog to be sure that the

$ sudo dnf install nginx

0 command you just issued was in

$ sudo dnf install nginx

1 rather than at

$ sudo dnf install nginx

2. As you can imagine, errors made as the root user can be irreversible and devastating. There is an alternative: sudo.

sudo

sudo, which is an acronym for superuser do or substitute user do, is a command that runs an elevated prompt without a need to change your identity. Depending on your settings in the

$ sudo dnf install nginx

5 file, you can issue single commands as root or as another user. To continue running commands with root power, you must always use the sudo command. For example, if you want to install the Nginx package, you run:

$ dnf install nginx

But you will see an error if you are not root or in the sudo group. Instead, if you run this command:

$ sudo dnf install nginx

You will be asked to type your password, and then you can run the command if you are a part of the sudo group.

A simple way to switch to an interactive session as a root user is the following:

$ sudo -i

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The theory behind using sudo is that the act of issuing the sudo command before any command you run makes you think more about what you're doing and hopefully make fewer mistakes with an account that possesses unlimited power.

su

su, on the other hand, is an acronym for switch user or substitute user. You are basically switching to a particular user and you need the password for the user you are switching to. Most often, the user account you switch to is the root account but it can be any account on the system.

For example, if you type:

$ su -

In the above example, you are switching to root and you need the root password. The (

$ sudo dnf install nginx

7) switch provides you with root's environment (path and shell variables) rather than simply giving you root user power for a single command while keeping your own environment.

$ su bryant

For the second example, you are switching to bryant, and so you need bryant's password unless you are root.

If you want to switch to the bryant user account including bryant's path and environment variables, use the (

$ sudo dnf install nginx

7) switch:

$ su - bryant

The (

$ sudo dnf install nginx

7) switch has the same effect as logging into a system directly with that user account. In essence, you become that user.

Wrap up

Recapping what you've learned.

sudo lets you issue commands as another user without changing your identity
You need to have an entry in
```
$ sudo dnf install nginx
```
5 to execute these restricted permissions
```
$ sudo -i
```
2 brings you to an interactive session as root
su means to switch to a particular user
Just typing su switches to the root user
sudo will ask for your password, while su will ask for the password for the user whom you are switching to

[ Want to learn more about security? Check out the IT security and compliance checklist. ]

But when do you use one, not another? Since the sudo policy is defined in

$ sudo dnf install nginx

5, this can give powerful permission controls. Since sudo can pretty much do everything that su can, I would say it is best to stick with sudo unless you are working with some legacy codes that require the su command.

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Topics: Linux Linux administration Security

Bryant Son

Bryant Jimin Son is a Consultant at Red Hat, a technology company known for its Linux server and opensource contributions. More about me

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Which Linux command can be used to let you run a single command as another user the root for example )?

3. Using su. su is a command-line tool that is commonly used to switch users in Linux. Additionally, it also allows us to execute scripts or commands as another user.

What command can you use to switch to a different user in Linux?

You can change the user ID associated with a session (if you know that user's login name) by using the su (switch user) command.

What command allows you to run a shell as a different user?

-u user The -u (user) option causes sudo to run the specified command as a user other than root. To specify a uid instead of a user name, use #uid.

Which command can be used to execute another command in Linux?

exec command in Linux is used to execute a command from the bash itself. This command does not create a new process it just replaces the bash with the command to be executed.

Sudo command Sudo specific command