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The Unix/Linux su (Substitute Person) command enables customers to become other people. This command was imagined to escalate privileges by turning out to be a privileged person for that reason, the default user is the root if no person is specified.

By executing the su command, you can become root or swap to any other person. This tutorial explains all su usages and the dissimilarities with the sudo command.

As stated earlier, if you execute the su command devoid of a user, you will come to be root by default, as shown in the screenshot below.

If you execute the su command followed by a user, you will become that consumer. Obviously, if you are root when you execute su, you will not be requested to variety the user’s password.

As you can see in the illustration over, the person changed from root to the specified person linuxhint. Still, the latest directory stays. You can put into practice the -l flag to change the recent directory for the goal user’s home directory, quickly relocating you from the present-day directory to the user’s house.

When applying the -l flag, not only the present directory improvements. Other options of this flag are:

  • Environment variables are cleared other than the Term variable for terminal dealing with and whitelisted variables.
  • Hundreds natural environment variables Person, LOGNAME, Property, SHELL, and Route.
  • Turns the shell into a login shell.
  • Changes the existing directory for the concentrate on user’s dwelling.

Another way to reproduce the similar habits is to change the -l flag for just a hyphen (), as demonstrated beneath.

As you can see, the user adjusted and also the recent listing.

The su command can be applied to operate commands as an additional person. As demonstrated in the examples beneath, including the -c (Command) flag enables you to execute commands with privileges devoid of turning into the root.

Initially, let us see what occurs if we attempt to examine the written content of the root listing devoid of being root:

As you can see, the user has no permissions to read through the root listing. As demonstrated underneath, this can be performed with the su command with the -c (Command) flag.

As you see in the syntax, you have to have to invoke the su command with the -c flag, followed by the instructions you want to run among quotation marks and followed by the user you want to run the command as, in this situation, the root user.

The runuser command:

There is an different for the su command named runuser. The big difference in between these two instructions is that runuser can only be applied by the root. The runuser command does not request a password, and it has a distinctive PAM (Linux Pluggable Authentication Modules) configuration.

As you might know, running browsers as root is forbidden, a bad exercise your technique should avert you from doing that.

If you are root and you want to launch an application unsafe as root, you can use both the su command, adopted by the -c flag as spelled out previously, or the runuser command shown in the case in point underneath, followed by the -u flag, the person you want to operate the command as, and the command you want to be executed.

runuser -u linuxhint firefox

The sudo command:

The sudo command is the most utilized alternate to operate instructions as a privileged user. It is a constrained strategy to get privileges. When using sudo, you won’t come to be root, but you will get permission to execute a specific command.

When applying the formerly defined su command, you need to fill in the goal consumer password. When applying sudo, alternatively of typing the concentrate on user password, you need to have to sort the latest user password if the person is in the sudoers team, he will be in a position to run the command if the user is not in the sudoers team, he will not be in a position.

Jogging a command as sudo is pretty simple just style sudo prior to the command as proven below.

For a user to be in a position to operate commands with sudo, you need to incorporate him to the sudoers group. To add a person to the sudoers group, run the following command.

Now the person can operate commands necessitating privileges by typing sudo.


The su, runuser, and sudo commands are simple to employ and are between the most simple Linux instructions any consumer ought to know. Learning how to use these commands will improve the stability from the person aspect (The most vulnerable). The sudo prefix for privileged instructions is the ideal different to preserve your system secure. Some Linux distributions mechanically disable the root login, leaving sudo as the default approach.

I hope this tutorial is displaying what the command su does and how to carry out it was practical. Retain pursuing this website for far more Linux ideas and tutorials.

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